[Oli Wright] is back again with another installation of CRT shenanigans. This time, the target is the humble analog oscilloscope, specifically a Farnell DTV12-14 12 MHz dual-channel unit, which features a handy X-Y mode. The result is the Velociraster, a simple (in hardware terms) Raspberry Pi Pico based display driver.

Using a Pico to drive a pair of AD767 12-bit DACs, the outputs of which drive the two ‘scope input channels directly, this breadboard and pile-of-wires hack can produce some seriously impressive results. On the software side of things, the design is a now a familiar show, with core0 running the application’s high-level processing, and core1 acting in parallel as the rendering engine, determining static DAC codes to be pushed out to the DACs using the DMA and the PIO.

The first demo is in vector mode, simply showing some simple shapes, to get an idea of the accuracy and linearity of the system. Next [Oli] shows a slick demo of a ‘starfield’ type effect, which renders different point brightnesses by accurately controlling the beam hold time. Next up is an  Asteroids-like game —which should be familiar to many — that shows off vector rendering with some nice particle effects visible due to the CRTs wide dynamic range.

[Oli] then goes on to show off raster mode, with an accurate-looking space invaders clone, followed by a static image showing some rudimentary grey-scale control mixed in with vector-mode graphics! There is an extra-special treat at the end of the video, which you’re not going to want to miss. No spoilers!

Some example code can be found in the examples repo, with the rendering library available here, for those who wish to play along at home.

Obviously driving a scope in XY mode with a computer is not a new trick, we’ve seen someone drive a (digital) Rigol to that effect, but CRTs just look, you know, cooler.

IBM’s Selectric line of typewriters were quite popular in the 1960s, thanks in part to an innovation called the typeball which allowed for easy font changes on a single machine. Unfortunately, as if often the case when specialized components are involved, it’s an idea that hasn’t aged particularly well. The Selectric typewriters are now around 60 years old and since IBM isn’t making replacement parts, those restoring these machines have had to get somewhat creative like using a 3D printer to build new typeballs.

It sounds like it would be a simple, but much like the frustration caused with modern printers, interfacing automated computer systems with real-world objects like paper and ink is not often as straightforward as we would like. The main problem is getting sharp edges on the printed characters which is easy enough with metal but takes some more finesse with a printed plastic surface. For the print, each character is modelled in OpenSCAD and then an automated process generates the 3D support structure that connects the character to the typeball.

This process was easier for certain characters but got more complicated for characters with interior sections or which had a lot of sharp angles and corners. Testing the new part shows promise, although the plastic components will likely not last as long as their metal counterparts. Still, it’s better than nothing.

Regular Hackaday readers may recall that the ability to 3D print replacement Selectric typeballs has been on the community’s mind for years. When we last covered the concept in 2020 we reasoned that producing them on resin printers might be a viable option, and in the end, that does indeed seem to have been the missing element. In fact, this design is based on that same one we covered previously — it’s just taken this long for desktop resin 3D printing technology to mature enough.

Nobody likes getting zapped from an electrostatic discharge, no matter whether you’re a fragile ASIC or a bag-of-mostly-salty-water humanoid. To prevent this, ESD wrist straps and similar are essential tools, as they prevent the build-up of a charge on your humanoid’s skin, essentially like a very large electrolyte-filled capacitor. Yet you can buy wireless ESD straps everywhere that are supposed to somehow dissipate this charge into the ether, even though this would seem to undermine the laws of physics that make capacitors work.

In a practical experimentation and assorted hijinks video collaboration by [Linus] from Linus Tech Tips and [Mehdi Sadaghdar] from ElectroBOOM put these wireless ESD straps to the test, featuring [Mehdi]’s DIY Van de Graaff generator to charge [Linus] up. What is excellently demonstrated in this video is how effective a real ESD strap is, and how the ‘wireless’ version is just a scam that does absolutely nothing to dissipate the charge, being just a waste of a 1 MOhm resistor and what could have been a real ESD strap.

Also covered in the video are what the reason for the resistor in an ESD strap is, and why metal bracelet type ESD straps are not appropriate, for very good reasons.

(Thanks to [hackbyte] for the tip)

Custom music instruments here at Hackaday range from wacky to poignant. OpnBeat by [Hiro Akihabara] focuses on something different: simplicity.

There are few buttons, the design and code are optimized to be straightforward and easy to modify, and the interface is slick. Eight musical keys complement three interface keys and a knob. An Arduino Nano powers the main brains of the system but the music generation comes from eight Nuvoton ISD1700s controlled over SPI by the Nano. The beautifully laid-out PCB is 110mm by 180mm (4.33″ by 7″), so cases can easily be printed on smaller FDM printers. All the switches are Cherry MX switches for the beautiful tactile feedback.

The code, PCB, and 3D case files are all available on GitHub. We love the thought that went into the design and the focus on making it easy to recreate. It might be quite as cute and simplified as this twelve-button musical macro pad, but the two together could make quite the band.

At first glance, the Raspberry Pi Pico might seem like a bit of a black sheep when compared to the other offerings from the Raspberry Pi Foundation. While most of the rest of their lineup can run Linux environments with full desktops, the Pico is largely limited to microcontroller duties in exchange for much smaller price tags and footprints. But that doesn’t mean it can’t be coerced into doing some of the things we might want a mainline Pi to do, like run a web server.

The project can run a static web page simply by providing the Pico with the project code available on the GitHub page and the HTML that you’d like the Pico to serve. It can be more than a static web page though, as it is also capable of running Python commands through the web interface as well. The server can pass commands from the web server and back as well, allowing for control of various projects though a browser interface. In theory this could be much simpler than building a physical user interface for a project instead by offloading all of this control onto the web server instead.

The project not only supports the RP2040-based Raspberry Pi Pico but can also be implemented on other WiFi-enabled microcontroller boards like the ESP8266 and ESP32. Having something like this on hand could greatly streamline smaller projects without having to reach for a more powerful (and more expensive) single-board computer like a Pi 3 or 4. We’ve seen some other builds on these boards capable of not only running HTML and CSS renderers, but supporting some image formats as well.

It doesn’t matter how you pronounce it, because whichever way you choose to say “GIF” is guaranteed to cheese off about half the people listening. Such is the state of our polarized world, we suppose, but there’s one thing we all can agree on — that a mechanical GIF is a pretty cool thing.

What’s even better about this thing is that [Mitch], aka [Hack Modular], put some very interesting old aircraft hardware to use to make it. He came upon a set of cockpit indicators from a Cold War-era RAF airplane — sorry, “aeroplane” — that used a magnetically driven rack and pinion to swivel a set of prism-shaped pieces to one of three positions. Which of the three symbols displayed depended on which faces were turned toward the pilot; they were highly visible displays that were also satisfyingly clicky.

After a teardown in which [Mitch] briefly discusses the mechanism behind these displays, he set about customizing the graphics. Rather than the boring RAF defaults, he chose three frames from the famous Horse in Motion proto-motion picture by [Eadweard Muybridge]. After attaching vertical strips from each frame to the three sides of each prism, [Mitch] came up with a driver for the display; he could have used a 555, but more fittingly chose series-connected relays to do the job. Capacitors slow down the switching cascade and the frame rate; a rotary switch selects different caps to make the horse appear to be walking, trotting, cantering, or galloping — yes, we know they’re each physically distinct motions, but work with us here.

The whole thing looks — and sounds — great mounted in a nice plastic enclosure. The video below shows it in action, and we find it pretty amazing the amount of information that can be conveyed with just three frames. And we’re surprised we’ve never seen these displays before; they seem like something [Fran Blanche] or [Curious Marc] would love.

Hackaday readers fit into two broad categories: those who experienced the wild and woolly early days of the Internet, and those who are jealous that they missed it. And it’s safe to say that both groups will get something out of this aggressively Web 1.0 retro experience, courtesy of a server that was actually part of it.

This comes to us via The Serial Port, a virtual museum dedicated to 90s technology, where curators [Mark] and [Ben] managed to find a pair of Cobalt RaQ 3 servers from the late 1990s. The RaQ was the first true “Internet appliance,” designed to be as simple as possible to set up and operate. If you wanted to get your small business online, machines like these were just the ticket. They were designed to be as plug-and-play as possible, and they did a pretty good job of it, at least for the time.

The machines that showed up were quite the worse for the wear, which is understandable given the decades since they were last relevant, but that just makes it all the more fun to get them going again. One didn’t even come close to booting, but the other showed more promise.

The video below is the first of a three-part series, and has a nice introduction to the RaQ and its important place in the early Internet, as well as a peek inside the two machines. That revealed some leaky caps that needed replacement in Part 2; after that minor surgery and a little persuasion, the 300-MHz screamer was ready for a test run. It worked, and The Serial Port put it right to work in Part 3 hosting a gloriously retro home page. Hit the link at the top of the article and enjoy the 90s all over again — the visitor counter, the mixed fonts, the “Under Construction” animated GIF, and the reminder to bookmark this page in your browser, which was probably Netscape Navigator. We love the guestbook, too. But — no marquee?

Nice job, [Mark] and [Ben], and kudos for keeping this little slice of computing history alive.

Looking back on what programming used to be like can be a fascinatingly entertaining thing, which is why [Tough Developer] decided to download and try using Turbo C and C++, from version 1.0 to the more recent releases. Borland Turbo C 1.0 is a doozy as it was released in 1987 — two years before the C89 standardization that brought us the much beloved ANSI C that so many of us spent the 90s with. Turbo C++ 1.0 is from 1991, which precedes the standardization of C++ in 1998. This means that both integrated development environments (IDEs) provide a fascinating look at what was on the cutting edge in the late 80s and early 90s.

It wasn’t until version 3.0 that syntax highlighting was added, with the IDE’s focus being mostly on features such as auto-indentation and tool integration. Version 2.0 added breakpoints and further integration with the debugger and other tools, as well as libraries such as the Borland Graphics Interface (BGI). Although even editors like Notepad++ and Vim probably give these old IDEs a run for their money nowadays, they were totally worth the money asked.

Those of us that have been around long enough to have gotten their start in C++ by using the free Turbo command line tools in the 1990s, or lived through the rough, early days of GCC 2.x+ on Linux, will remember that a development environment that Just Worked^© was hard to obtain without shelling out some cash. Within that environment Turbo C and C++ and later Visual Studio and others served a very grateful market indeed.

Beyond the IDE itself, these also came with language documentation, as in the absence of constant internet access, referencing APIs and syntax was done using dead-tree reference books or online documentation. Here “online” meaning digital documentation that came provided on a CD and which could be referenced from within the IDE.

[Tough Developer] walks the reader through many features of the IDE, which includes running various demos to show off what the environment was capable of and how that in turn influenced contemporary software and games such as Commander Keen in Keen Dreams. While we can’t say that a return to Turbo C is terribly likely for the average Hackaday reader, we do appreciate taking a look back at older languages and development environments — if for no other reason than to appreciate how far things have come since then.

Despite having been technologically obsolete for a decade or two, analog photography is still practiced by hobbyists and artists to achieve a particular aesthetic. One might imagine a similar thing happening with early digital cameras, and indeed it has: the Game Boy Camera has seen use in dozens of projects. [Michael Fitzmayer] however decided to combine the worlds of analog and early digital photography by equipping a Holga with the image sensor from a Game Boy Camera.

The Holga, if you’re not familiar, is a cheap film camera from the 1980s that has achieved something of a cult following among retro-photography enthusiasts. By equipping it with the sensor from what was one of the first mass-market digital cameras, [Michael] has created a rather unusual digital point-and-shoot. The user interface is as simple as can be: a single button to take a photo, and nothing else. There’s no screen to check your work — just as with film, you’ll have to wait for the pictures to come back from the lab.

The sensor used in the Game Boy Camera is a Mitsubishi M64282FP, which is a 128 x 128 pixel monochrome CMOS unit. [Michael] hooked it up to an STM32F401 microcontroller, which reads out the sensor data and stores it on an SD card in the form of a bitmap image.

With no film roll present, the Holga has plenty of space for all the electronics and a battery. The original lens turned out to be a poor fit for the image sensor, but with a bit of tweaking the Game Boy optics fit in its place without significantly altering the camera’s appearance.

[Michael] helpfully documented the design process and shared all source code on his GitHub page. Holgas shouldn’t be hard to find to find, but if none are available in your area you can just roll your own. The Game Boy Camera is actually one of the most versatile cameras out there, having been used for everything from video conferencing to astrophotography.

We’re not sure, but the number of recognizable alphanumeric characters that a seven-segment display can manage seems to have more to do with human pattern recognition than engineering. It takes some imagination, and perhaps a little squinting, to discern some characters, though. Arguably better is the fourteen-segment display, which has been pressed into service in this just-for-funsies IOT message board.

As [Steve] tells the story, this is one of those “boredom-buster” projects that start with a look through the junk bin to see what presents itself. In his case, some fourteen-segment common-cathode LEDs presented themselves, and the result was a simple but fun build. [Steve] used some clever methods to get the display stuffed onto two protoboards, including mounting the current-limiting resistors cordwood-style between the boards. A Raspberry Pi drives the display through a very neatly routed ribbon cable, and the whole thing lives in a tidy wooden box.

The IOT part of the build allows the display to show messages entered on [Steve]’s web page, with a webcam live stream to close the loop. Strangely, the display seems stuck on the “HI HACKADAY!” we entered as a test after [Steve] tipped us off, so we’re not sure if we busted it or what. Apologies if we did, [Steve]. And by the way, if your cats are named [Nibble] and [Pixel], well done!

No matter what you do with them, multi-segment displays are pretty cool. But if you think they’re something new, you’ve got another think coming.

[IMSAI Guy] has an old HP 3488A Switch Control Unit that he wants to dismantle for parts ( see video below the break ). The 3488A is pretty simple as far as HP test equipment goes — a chassis that can hold various types of relay cards and is programmable over GPIB. He notes up front that these are plentiful and inexpensive in the used test equipment market.

Around the back of the unit is a card cage that accepts up to five option cards providing

• 4×4 matrix switching
• on/off SPST switching
• switching signals to a common bus
• VHF switching
• Digital I/O signalling

The teardown is an interesting glimpse into the solid engineering design of 1980s HP test equipment. The option cards are well shielded, and have an interesting back panel connector that breaks out the signals to screw terminals and provides strain relief. The brains of switcher was a Motorola 6809 and connectivity was provided by an Intel 8291A GPIB interface chip. The power supply is solid, and many of its parts can be reused on other projects, such as the transformer and a beefy 20W DC-DC converter by ST. [IMSAI Guy] also scores a bunch of latching relays from the option cards which will no doubt come in handy on future projects.

These kinds of programmable relays can be very useful when building automated test fixtures. There were other solutions for this as well, back in the day. Metrabyte ( bought by Keithley, bought by Tektronix ) was one company that made a whole line of switching interface modules that hooked up to your PC’s ISA bus. Omron also offered similar products. Have you ever needed banks of programmable relays for your projects? If so, let us know your solution in the comments below.

For a device advertised as the “Multi-tool Device for Hackers”, the Flipper Zero already offers a considerable list of onboard capabilities. But some hard decisions had to be made to get the retail price down, so features like WiFi and Bluetooth had to be left off. Luckily, there’s an expansion interface along the top of the device which makes it possible to plug in additional hardware.

One of those expansions is the “Mayhem Hat” from [Erwin Ried]. This board adds many requested features to the Flipper Zero, as well as some that might not seem as obvious. The addition of an ESP32-CAM brings WiFi and Bluetooth to the party, while also unlocking access to the highly-capable ESP32Marauder firmware and the plethora of security research tools therein.

But the camera also enables some interesting features, such as motion detection and the ability to read QR codes. It even lets you use the Flipper as an impromptu digital camera, complete with an onscreen viewfinder reminiscent of the Game Boy Camera.

What’s more, the Mayhem Hat features its own expansion capabilities. There’s a spot to plug in either a CC1101 or NRF24l01 radio module, both of which are supported by community developed plugins that allow the user to sniff out and hijack signals. There are also extra pins for connecting your own sensors or hardware. In the demo video below you can see the device automatically detect the popular DHT11 environmental sensor and display the current temperature and humidity readings.

[Erwin] has the Mayhem Hat up for sale on Tindie, but as of this writing, is currently out of stock. Apparently, demand for the add-on boards is just as high as for the Flipper Zero itself — not a huge surprise, given the excitement we saw around this platform during its $4.8 million Kickstarter campaign.

What is it about pi that we humans — at least some of us — find so endlessly fascinating? Maybe that’s just it — it’s endless, an eternal march of digits that tempts us with the thought that if we just calculate one more digit, something interesting will happen. Spoiler alert: it never does.

That doesn’t stop people from trying, of course, especially when “Pi Day” rolls around on March 14 every day  — with apologies to the DD/MM set, of course. This year, [Cristiano Monteiro] commemorated the day with this Pi-based eternal pi calculator. The heart of the build is a Raspberry Pi Pico board, which does double duty thanks to its two cores. One core is devoted to running the pi calculation routine, while the other takes care of updating the seven-segment LED display with the last eight calculated digits. Since the calculation takes increasingly more time the farther into pi it gets, [Cristiano] thoughtfully included a 1-Hz heartbeat indicator, to assure users that the display isn’t frozen; the video below shows how slow the display gets even just a few seconds after starting up, so it’s a welcome addition.

This is actually [Cristiano]’s second go at a Pi Day pi calculator; last year’s effort was a decidedly tactical breadboard build, and only supported a four-digit display. We applaud the upgrades, and if anyone wants to replicate the build, [Cristiano] has posted his code.

While you might think the military doesn’t have a sense of humor with names. Take the AN/MSQ-19 “automated tactical operations central” for example. (Video, embedded below.) But then, when you find out that the truck-sized computer at the heart of it was MOBIDIC — yes, that’s pronounced Moby Dick — you know someone had a good chuckle somewhere. The video below was a promotional video from the early 1960s, and although it shows the unit in operation, it was most likely a mockup and not fully functional.

The MOBIDIC program ran from 1960-1964 and cost a whopping $25 million in 1960-era money. In 1964, testing revealed the system was too unwieldy, requiring at least five tractor-trailers, eight generators, portable buildings, and several large trucks to move around.

Graphical Output?

We doubt the system could have been very reliable, either. It relied on a Rube Golbergesque system to record and file transparencies that were projected on maps. These transparencies were stored in some sort of automatic filing system and carried around in pneumatic tubes. No kidding, watch the video. You can’t make this stuff up.

A 1966 report from an Army research lab discusses using parts of AN/MSQ-19 in a laboratory, so at least some of the high-tech equipment did find a home. The designers of the system weren’t wrong, they were just a little early and needed better graphics capabilities along with smaller computers. The MOBIDIC weighed about 12,000 pounds, although at least the “B” version used by this project did have dual CPUs! There was a unique input device called a Grafton which was sort of like a modern digitizer. Sort of.

MOBIDIC

The MOBIDIC was built late in the 1950s as part of a larger Army strategy to computerize. You can watch a video about the solid-state computer in the second video below. It even includes a contemporary film about the computer. The base machine had 32,000 transistors, 6,000 diodes, and 311,200 bits of magnetic core. That’s less than 40 kB, to save you the math, and the narrator on the Army’s film calls that a “huge memory.” Perhaps he was really referring to the giant tape drives, which could hold about 10 MB. Not huge by today’s standards, of course, but still.

The trailer/computer had six tape drives, several cabinets for memory with space reserved for future upgrades, and an air conditioner. With power and extra equipment, there were actually four trailers together. There were several variants of these computers produced, and some saw actual use, particularly in Germany. The National Bureau of Standards bought the MOBIDIC-B used in this system and you can read about its retirement in 1973.

They Simply Fade Away

Sylvania, the MOBIDIC’s developer, also produced the 9400, a commercial variant of the machine. What was it like to program? Well, you used BASICPAC, which didn’t look at all like BASIC, if you were wondering.

Looking back over the 60-some-odd years between this system and our modern computers, you could choose to be amused at how primitive the systems were. Or, you can stand in awe that people could look at this new technology and see what could be possible, even if they weren’t quite able to get there right away.

The Xerox Alto, which debuted in the early spring of 1973 at the photocopying giant’s newly established R&D laboratory, the Palo Alto Research Center (PARC). It seems so uncannily familiar today for one reason: We are now living in a world of computing that the Alto created.

The Alto was a wild departure from the computers that preceded it. It was built to tuck under a desk, with its monitor, keyboard, and mouse on top. It was totally interactive, responding directly to its single user.

In contrast, the dominant mainframe at the time—IBM’s hugely popular System 360, heavily used by big organizations, and the Digital Equipment Corp.’s PDP-10, the darling of computing researchers—were nothing like the Alto. These and the other mainframes and minicomputers of the era were room-size affairs, almost always located somewhere away from the user and almost always under the control of someone else. The many simultaneous users of one such computer shared the system as a common resource.

Steve Jobs and a whole team from Apple toured PARC in 1979. The visit was arranged as a quid pro quo for allowing Xerox to invest in Jobs’s exciting new personal-computer company. Viewing Alto’s graphical user interface, Jobs had what he later described as an epiphany, one that reoriented his efforts at Apple forever after.

See a restoration video below and read more about Alto and the revolution it sparked in IEEE Spectrum.

Early home PCs usually had a floppy disk and a simple hard drive controller. Later, IDE hard drives became the defacto standard. Of course, these days, you are more likely to find some version of SATA and — lately — NVME connectors. But a standard predating all of this was very common in high-end systems: SCSI. [RetroBytes] recently did a video on the bus which he calls the “USB of the 80s.”

Historically, Shugart — a maker of disks — was tired of producing custom drive electronics for each device they made. Instead, they made disks with a standard interface and then produced a single interface board for each computer they wanted to support. The interface was very generic, and they were able to get it standardized with ANSI — an early example of the benefit of opening up a standard.

SCSI could connect to many things besides disks, like scanners and tape drives. You could even find SCSI to network adapters. It was fast for its day,  too. There were also updated standards that pushed performance higher over time. In addition to a standard hardware interface, most SCSI devices didn’t need special device drivers.

There were a few cheap SCSI host adapters for the PC, like the Seagate ST01 and ST02, but they weren’t good performers. Fast interfaces were pretty expensive. The other hard drive connectors were cheaper and didn’t require complicated termination and expensive cables. So SCSI rapidly lost ground in the PC, and as the PC market grew, it started pushing out SCSI in personal computers. But high-end workstations used SCSI because it performed better, and [RetroBytes] has an extensive explanation of why it was faster than early hard drive standards.

The video does a nice job of showing off some grand old hardware and many use cases for SCSI like RAID arrays and shared storage. If you have the urge to walk down memory lane or you like learning about old technology, this video is worth a read. SCSI is still around, by the way, although now it is a serial standard that is very similar to SATA. It just isn’t nearly as prevalent as it used to be. You can bridge USB and SCSI, if you can find the hardware. You can also put today’s tiny computers on the bus and have them pretend to be disk drives.

[Mike Harrison] has an upcoming project which will combine a large number of flip-dot displays salvaged from buses. [Mike] thought he knew how these things worked, and had a prototype PCB made right away. But while the PCB was being manufactured, he started digging deeper into the flip-dot’s flipping mechanism.

As he dismantled one of the flip-dots, he realized there was a lot going on under the hood than he realized. The dots are bistable — staying put when power is removed. This is achieved with a U-shaped electromagnet. The polarity of a driving pulse applied to the coil determines which way to flip the dot and saturates the electromagnet’s core in the process. Thus saturated, each dot is held in the desired position because the black side of the dot is made from magnetic material. But wait, there’s more — on further inspection, [Mike] discovered another permanent magnet mounted in the base. He’s not certain, but thinks its job is to speed up the flipping action.

Besides curiosity, the reason [Mike] is studying these so closely is that he wants to build a different driver circuit to have better and faster control. He sets out to better understand the pulse waveform requirements by instrumenting a flip-dot and varying the pulse width and voltage. He determines you can get away with about 500 us pulses at 24 V, or 1 ms at 12 V, much better that the 10 ms he originally assumed. These waveforms result in about 60 to 70 ms flip times. We especially enjoyed the slow-motion video comparing the flip at different voltages at 16:55 in the video after the break.

[Mike] still has to come up with the optimum driving circuit. He has tentatively has settled on a WD6208 driver chip from LCSC for $0.04/ea. Next he will determine the optimum technique to scale this up, deciding whether going for individual pixel control or a multiple sub-array blocks. There are mechanical issues, as well. He’s going to have to saw off the top and bottom margin of each panel. Reluctant to unsolder the 8500+ joints on each panel, his current idea is to solder new controller boards directly onto the back of the existing panels.

This video is a must-watch if you’re working on drivers for your flip-dot display project, and we eagerly look forward to any future updates from [Mike]. We also wrote about a project that repurposed similar panels a couple of years ago. There are a few details that [Mike] hasn’t figured out, so if you know more about how these flip-dots work, let us know in the comments below.

wbaiv has added a photo to the pool:

Here's the red phone already described, and four more telephone dials

wbaiv has added a photo to the pool:

Aft bulkhead of CVS 12 USS Hornet Combat Information Center. Note communications switchery, knobs, lamps, telephone dials (4, can you find them?) This elevated platform gave the officer on watch a view over the airborne sonar sensor data, surface and air search radar data, air traffic control radar and all the other data summarized and presented in grease pencil, written backwards, on glass panels along the starboard, port and forward bulkheads of the room. A red telephone, just outside the left edge of this picture, gave scrambled, secure, voice access to the Pentagon or White House situation room. Pick up this end and an officer there would always answer. A black and two gray handsets gave access the Officer of the Deck on the bridge, any other handset on the ship, to local voice radio network including Hornet, her escorting destroyers and other surface vessels, (TBS - Talk Between Ships as it was called in WWII) and radio links to aircraft operating from Hornet. And anyone else the CIC needed to speak with, or who needed the speak with CIC.

My friend Ken is taking pictures of a US and a Soviet / Russion sonarbuoy on the table in the ante-compartment.

wbaiv has added a photo to the pool:

Note distinctively colored and shaped knobs above the below the screen for the operator to find and operate by hand. 5 knobs are visible above the screen, with two yellow knobs left and right, two blue, triangular, knobs and a red, ruffled edge knob, centered. Two more blue triangles and a warm-colored "+" shaped knob are above the screen but below the ones you can see there. Two white knobs with small, flat, grips are below the display screen.

The black panel on the right appears to provide radio channel selection among different nets

The humble desktop serial terminal may have long disappeared from the world of corporate IT, but there are still plenty of moments when professionals and enthusiasts alike need to hook up to a serial port. Many of us use a serial port on our laptops or other mobile devices, but [Neil Crawforth] has gone one better than that with the VT2040. It’s an old-style serial terminal in a super-handy portable format, and as one might guess from the name, it has an RP2040 microcontroller at its heart.

Attached to the chip is a rather nice keyboard, and an ILI9488 480×320 LCD display. The software is modular, providing a handy set of re-usable libraries for the different functions including a PIO-based serial port. His main application seems to be talking to an ESP8266, but we’re guessing with a MAX232 or other level shifter chip it could drive a more traditional port. Everything can be found in the project’s GitHub repository, allowing anyone to join the fun.

As long-time readers will know, we’ve been partial to a few serial terminals in the past. Particularly beloved is this extremely retro model with vintage dot matrix LEDs.

If you’re making a lot of wiring harnesses, wrapping them can become a bit of a drag. [Well Done Tips] wanted to make this process easier and built a wiring harness wrapping machine.

The “C” shape of this wrapping machine means that you can wrap wires that are still attached at one or both ends, as you don’t have to pull the wires all the way through the machine. The plastic “C” rotates inside a series of pulleys with three of them driven by a belt attached to an electric motor. A foot pedal actuates the motor and speed is controlled by a rotary dial on the motor controller board.

Since this is battery powered, you could wrap wires virtually anywhere without needing to be near a wall outlet. This little machine seems like it would be really great if you need to wrap a ton of wire and shouldn’t be too complicated to build. Those are some of our favorite hacks.

If you’re wanting more wire harness fun, try this simple online wiring harness tool or see how the automotive industry handles harnesses.

Even if you didn’t own a TRS-80, the widespread footprint of Radio Shack in malls meant that if you are old enough, it is a good bet you have seen one and maybe even played with one. The games were crude, but state-of-the-art for 1982. If you wanted business software, that was there too, just don’t expect much on any of the personal computers of the day. My old TRS-80 Model III doesn’t boot anymore and is waiting for me to find time to pull it apart. But it turns out you can run all those old programs with almost no effort. If you’ve experimented with emulators before, you know there are two major problems. First, you need to install the sometimes-fidgety emulator. Second, you need to find the software you want to run and probably convert it into some format the emulator will read. The website named The Big List of TRS-80 Software solves both problems.

You are probably thinking this doesn’t solve any problem because it is just a list of links to software. That’s a reasonable thing to think, but we think the website really needs a new name. There are 15,873 pieces of software on the site, although some of them are duplicates or multiple versions of a single program. You can download them in a format that is useful for some emulators or, in some cases, the original files. But here’s the kicker. You can also click to launch a virtual TRS-80 in your browser and start the program.

Sounds great, right? Well, for the most part, it is. However, some of the programs are finicky and don’t run well in the browser. There’s also the problem of finding the documentation, but you can’t have everything. If you want a quick run of a very common game from back in the day, try Flying Saucers.

A Tale of Two Emulators

The browser-based emulator is from [Peter Phillips]. If the program you want to run doesn’t work well in the browser, you might want to try trs80gp, a full-featured stand-alone emulator that can run the DMK files you can download from the list.

The trs80gp software can emulate just about every TRS-80 and variant including the Model II and MC-10 Color Computer. The emulator is simply amazing. It not only emulates complete systems with cassettes, floppies, or hard drives, but it can even emulate the terrible display you’d expect from a vintage 1980s computer.

The emulator can slow down or run at full speed. You can even have cassette audio output captured automatically on the PC. Unfortunately, one of my old favorites — Asylum — acts the same in both emulators. It starts up, asks you a yes or no question, and refuses to accept any keyboard input. Keyboard input works for other programs, though. Even the emulator’s on-screen keyboard (both of them have one) won’t put input into this and a few other programs I tried.

Trash-80 Wine

There is a problem with the stand-alone emulator, though. There are versions available that don’t require Windows. However, the website mentions that the Windows version has more features. It does, however, run under Wine. In my case, I installed it using Crossover Office, which is a paid version of Wine. I can confirm that it works great.

If you find a program you want to try on the list, you can start with the AUTORUN link to run it directly in the browser. If you prefer, you can download the DMK file and mount it as a floppy on the stand-alone emulator. Some floppies are bootable, and others require you to use the second drive with a standard boot floppy in the main drive. Don’t forget, the drives are numbers in TRSDOS and most other TRS-80 operating systems. So DIR :1 will list the files on the secondary drive.

If things don’t work, you can try the DEBUG link. This lets you select if you want to boot under DOS Plus, LDOS, NewDos-80, or TRSDOS. Another option is to pick up the individual files. You can’t download these files directly from the table. Instead, you click on the file name, and a page will show you the file along with several options.

You can pick a few options for emulating or downloading the program from that page. You can also show and download the program parsed as a BASIC file, a text file, a Z80 program, or a  few other formats. The “Hex File” option, as far as I can tell, actually means raw, not an Intel hex format file. You can even edit the program in place and emulate it if you like, although for machine language programs, that will be difficult.

If you want a few things to try in addition to the UFO game mentioned above, try Battle Trek, or try your hand at word processing (type SCRIPSIT at the prompt). Just be prepared to explore the disks, run a few things, and maybe Google some old user manuals.

Practical?

Is all this practical? No way. But if you enjoy computer history, this is an easy way to poke around in what would have been a truly extensive software library in its day. Sure, a real TRS-80 would be even more fun. But it would also be a lot more work, not the least of which would be transferring media around.

Then again, you could build a clone. Or play with some other browser-based retro computers.

A playable game of Doom on two tiny LEGO bricks. An accelerometer uses tilt to move and pressing the top right connector shoots. It uses a monochrome 0.42″ OLED screen, available from aliexpress or similar. The display uses subframe sampling to get shades of grey. The MicroPython code is on GitHub.

The project uses a Raspberry Pi RP2040 microcontroller.

See the use video below, the build video and more on YouTube.

In the rare case we listen to an audio CD these days, we typically rely on off-the-shelf hardware to decode the 1s and 0s into the dulcet tones of Weird Al Yankovic for our listening pleasure. [Lukas], however, was recently inspired to try decoding the pits and lands of a CD into audio for himself.

[Lukas] did the smart thing, and headed straight to the official Red Book Audio CD standard documents freely available on archive.org. That’s a heck of a lot cheaper than the €345 some publishers want to charge. Not wanting to use a microscope to read the individual pits and lands of the disc, [Lukas] used a DVD player. The electrical signals from the optical pickup were captured with an oscilloscope. 4 megasamples of the output were taken at a rate of 20 megasamples per second. This data was then ported over to a PC for further analysis in Python.

[Lukas] steps us through the methodology of turning this raw data of pits and lands into real audio. It’s a lot of work, and there are some confusing missteps thanks to the DVD player’s quirks. However, [Lukas] gets there in the end and shows that he truly understands how Red Book audio really works.

It’s always interesting to see older media explored at the bare level with logic analyzers and oscilloscopes. If you’ve been doing similar investigative work, don’t hesitate to drop us a line! 

Apple is often lauded for its design chops, but function is often sacrificed at the altar of form, particularly when repair is involved. [Ken Pillonel] has made it easier for everyone to replace the batteries or lightning port in the AirPods Pro case. (YouTube)

With such notable hacks as adding USB C to the iPhone already under his belt, [Pillonel] has turned his attention to fixing the notoriously poor repairability of AirPods and AirPods Pro, starting with the cases. While the batteries for these devices are available, replacement Lightning ports are not, and taking the housing apart for the case is an exercise in patience where the results can’t be guaranteed.

He designed a USB C replacement port for broken Lightning ports that is a perfect fit if you happen to get the case apart in one piece. If you’re less successful, he has you covered there too with a 3D printable enclosure replacement.

We sure miss the days of schematic proliferation here at Hackaday, but we know you don’t let glued enclosures or unobtainium parts stand in the way of repairs.

[Jacek Fedorynski] had an old Magellan/SpaceMouse 3D mouse with a serial interface which made it impossible for him to use with modern hardware and software. The problem he faced was two pronged – the absence of serial interfaces in the hardware and the lack of appropriate drivers for the operating system. So he built a low cost, simple adapter to use his RS-232 Magellan/SpaceMouse with modern software.

The hardware required to build the adapter was minimal. A Raspberry Pi Pico, a MAX3238 based RS-232 adapter, a null modem adapter and a DB9 gender changer. Of course, a combination null modem – gender changer would have made things even simpler. Four of the GPIO pins from the Pico are mapped to the serial RX, TX, RTS and CTS pins.

On the software side, the code emulates a 3DConnexion SpaceMouse Compact, so it can be used with software like Fusion 360, 3ds Max, SolidWorks, Inventor, Maya and many others. On the host computer, only the standard 3DxWare driver package is needed. On the host computer, the old Magellan/SpaceMouse 3D will appear like a modern SpaceMouse Compact connected over USB. The only downside to this is that the SpaceMouse Compact has just two programmable buttons, so only two of the many buttons on the old Magellan mouse can be mapped.

Flashing the code to the Pico is also straightforward using the BOOTSEL mode. Hold down the BOOTSEL button when plugging in the Pico and it appears as a drive onto which you can drag a new UF2 file. Just drag-n-drop [Jacek]’s magellan.uf2 firmware and you’re done.

If you’d rather build your own, modern 3D mouse, check out the DIY Cad Mouse You Can Actually Build.

ICYMI (In case you missed it) – the IoT Monthly Newsletter from AdafruitDaily.com went out this morning!

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IoT Projects

Waving Cat Doorbell

A “Maneki-Neko” cat gains “enhanced cat biceps” with a servo and waves when the door to an apartment has been opened. – Hackaday.io

IoT AI-assisted Deep Algae Bloom Detector

Detecting harmful algae blooms and toxins using machine learning. – Hackaday.io

Connecting a complicated boiler system to Home Assistant

Gray Malk’s home has an unconventional heating system. There’s a heating zone for the upstairs (using radiators) and then another for downstairs (using underfloor heating). Due to this, they found none of the off-the-shelf solutions would work, except for a £300 option. In the blog, they detail how they rolled their own custom solution. – Gray Malk

Having fun with hyperlocal data

Alex S. writes about using the Pimoroni wireless sensors to send all kinds of hyperlocal data to the internet. – lagomor.ph

IoT News and More!

Taking over a Dead IoT Company

Kevin Chung writes about the collapse of NYCTrainSign and how they ended up writing an exploit to take over their entire fleet. – blog.kchung.co

6 Smart Home Finds from CES 2023 (that aren’t about the Matter standard)

This year’s CES event came and went with a lot of talk about the new Matter standard. The Verge recaps a few products on the show floor that weren’t focused on Matter. – TheVerge

Dracula Sucks Indoor Light to Power IoT Devices

Given the hungry power needs of the rapidly expanding realm of the Internet of Things, clever solutions are needed to generate and conserve energy consumed by these devices. One such solution is Dracula. No, not the blood-sucking Transylvanian count, the ambient indoor light-sucking technology. – Adafruit Blog

Support Adafruit

Here at Adafruit, we sell all of these amazing components, but we couldn’t find a good way to interact with them over the Internet. So, we decided to create our own IoT platform, and that’s Adafruit IO. It’s built from the ground up to be easy to use and platform agnostic (connect any development board or device!).

For those who want to get a project off the ground without programming – Adafruit IO offers a No-Code interface for building IoT electronics projects using WipperSnapper, our open-source IoT firmware. Support Adafruit’s open-source development by subscribing to Adafruit IO Plus, the upgraded, all-systems-go version of the Adafruit IO service.

Unless your computer is pretty old, it probably uses UEFI (Unified Extensible Firmware Interface) to boot. The idea is that a bootloader picks up files from an EFI partition and uses them to start your operating system. If you use Windows, you get Windows. If you use Linux, there’s a good chance you’ll use Grub which may or may not show you a menu. The problem with Grub is you have to do a lot of configuration to get it to do different things. Granted, distros like Ubuntu have tools that go through and do much of the work for you and if you are satisfied with that, there’s no harm in using Grub to boot and manage multiple operating systems.

An alternative would be rEFInd, which is a nice modern UEFI boot manager. If you are still booting through normal (legacy) BIOS, the installation might be a hassle. But, in general, rEFInd, once installed, just automatically picks up most things, including Windows, Mac, and Linux operating systems and kernels. The biggest reasons you might change the configuration is if you want to hide some things you don’t care about or change the visual theme.

Basics

A UEFI computer stores boot information in nonvolatile RAM. You can examine this and even make some changes using the Linux utility efibootmgr:

$ efibootmgr
BootCurrent: 0004
Timeout: 1 seconds
BootOrder: 0004,0003,0001,0002,0005,0006
Boot0001* UEFI OS
Boot0002* UEFI:CD/DVD Drive
Boot0003* ubuntu
Boot0004* rEFInd Boot Manager
Boot0005* UEFI:Removable Device
Boot0006* UEFI:Network Device

Generally, you won’t want to directly add or delete things using this tool, even though you can. Usually, your operating system takes care of all that. However, it is a pain to pick one partition over the other if you, for example, boot Windows and Linux. You can see from the above dump that I don’t do this, at least not on this computer. However, I do often boot from a removable disk or have multiple kernels or even operating systems installed in different places.

Grub can handle all this, of course. Especially if you use a distribution with a lot of tools, they will scan, looking for things, and rebuild your grub configuration. But if that configuration ever goes bad and you forget to build, look out! Time to boot from a rescue disk, more than likely. Grub is both a boot loader and a boot menu. But rEFInd is a boot menu manager only.

Pros and Cons

There are several reasons you might opt for rEFInd. The biggest practical reason is that it scans for bootable items on every boot. It is also nice looking and can support touchscreens and mice, but not both at the same time. There was an Ask Ubuntu post where the author of rEFInd listed the pros and cons between his code and Grub. His advantages list include:

• Scans for new kernels on every boot
• Eye candy
• Reliable booting fo Windows with secure boot active
• Able to launch BIOS-mode bootloaders
• Ability to speed up installs if you don’t install Grub at all
• Strict enforcement of secure boot policies

Of course, there are also some downsides. Grub is the “official” way to handle things for most distributions and you can assume distros and tools will be compatible with it. It relies primarily on a single developer. Grub is easier to use with networking, LVM, and RAID booting, although these are possible with rEFInd, too. Because rEFInd scans on each boot, there is a brief pause when you boot, of course.

It is possible to have rEFInd boot into Grub, and that can be useful sometimes, but in general, you’ll want to use rEFInd instead of the Grub menus. One exception is if you want an emergency USB drive with rEFInd on it, that might be useful since it can mostly configure itself.

Install

If you use a distro that can handle Ubuntu PPAs, installing the program is simple.

sudo apt-add-repository ppa:rodsmith/refind
sudo apt-get update
sudo apt-get install refind

You can also find detailed instructions on installing in special cases on the project’s website. Once you install, you probably don’t have to do anything, but you might want to browse the configuration file (something like /boot/efi/EFI/refind/refind.conf). There you can adjust a few things like timeouts, default kernel options, and the like. There are quite a few options, but most of them are commented out.

You can also make manual entries, much like Grub. There are several examples in the default configuration file, but you’ll notice they all have the disabled keyword in them, so you would remove that keyword after making changes to suit you. You can also pick a text-based mode, the default screen resolution, and other parameters. I changed the line to show some tools (like reboot or boot into BIOS setup) that were not on by default. In many cases, you won’t need any changes at all.

If you see entries on the screen you don’t want, highlight them and press the minus sign. Don’t worry, you can manage the “hidden tags” using a menu if you change your mind later.

Be warned that while the system does support secure boot, if you use it, it may need a little tweaking. Here’s the good news. If it doesn’t work, just change the boot order back to boot Grub first and you can troubleshoot from there.

Themes

One fun thing you can do is get different themes for the program. These are just collections of artwork used as the banner and as icons for different distributions. For some reason, the program didn’t automatically pick up my Neon with the Neon logo, even though it was present. My simple solution was to replace the default Tux penguin with a copy of the Neon logo.

I’ve read that pressing F10 will screenshot rEFInd, but apparently, I don’t have the latest version, so I had to rely on my phone to take an old-school screenshot. You can see why I changed the penguin logo.

The tools along the bottom let you run a memory test, or reboot and shut down. You can also launch an EFI shell or alter the EFI boot order.

Low Risk

Any time you dink with the booting of your computer, you are taking a risk. However, if you install with Grub, you can always leave it as an option from rEFInd. If you get in big trouble, Grub is still there and you can boot from a rescue medium and use efibootmgr to pick your default Grub setup. The documentation for rEFInd has a good writeup on what the author calls “boot coups” when an operating system — looking at you, Windows — presumptively takes over booting.

If you don’t dual boot, you can probably stick with Grub. It is nice to have a more modern-looking boot menu, but it isn’t that compelling. But if you dual boot with Windows, Mac, or other EFI-capable operating systems, or even if you change kernels often, you should really check out rEFInd.

For some specialized cases, you might want to check out a specialized fork of rEFInd, which offers certain additional features. You can find out more about the differences on its home page.

If you want more technical details on UEFI, here you go. Of course, as Scotty famously said, “The more they overthink the plumbing, the easier it is to stop up the drain.” UEFI is a big attack target, and it has been hit before.

Many mainboards and laptops these days come with a range of M.2 slots, with only a subset capable of NVME SSDs, and often a stubby one keyed for ‘WiFi’ cards. Or that’s what those are generally intended to be used for, but as [Peter Brockie] found out when pilfering sites like AliExpress, is that you can get a lot of alternate expansion cards for those slots that have nothing to do with WiFi.

Why this should be no surprise to anyone who knows about the M.2 interface is because each ‘key’ type specifies one or more electrical interfaces that are available on that particular M.2 slot. For slots intended to be used with NVME SSDs, you see M-keying, that makes 4 lanes of PCIe available. The so-called ‘WiFi slots’ on many mainboards are keyed usually for A/E, which means two lanes of PCIe, USB 2.0, I2C and a few other, rather low-level interfaces. What this means is that you can hook up any PCIe or or USB (2.0) peripheral to these slots, as long as the bandwidth is sufficient.

What [Peter] found includes adapter cards that add Ethernet (1 Gb, 2.5 Gb), USB 2.0 ports, SIM card (wireless adapter?), an SFP fiber-based networking adapter, multiple M.2 to 2+ SATA port adapters, tensor accelerator chips (NPUs) and even a full-blown M.2 to x16 PCIe slot adapter. The nice thing about this is that if you do not care about using WiFi with a system, but you do have one of those ports lounging about uselessly, you could put it to work for Ethernet, SFP, SATA or other purposes, or just for hooking up internal USB devices.

Clearly this isn’t a market that has gone unexploited for very long, with a bright outlook for one’s self-designed M.2 cards. Who doesn’t want an FPGA device snuggled in a PCIe x2 slot to tinker with?

(Thanks to [RebootLoop] for the tip!)

Whenever [Ken Shirriff] posts something, it ends up being a fascinating read. Usually it’s a piece of computer history, decapped and laid bare under his microscope where it undergoes reverse engineering and analysis to a degree that should be hard to follow, but he still somehow manages to make it understandable. And the same goes for this incredible Soviet analog flight computer, even though there’s barely any silicon inside.

The artifact in question was officially designated the “Индикатор Навигационный Космический,” which roughly translates to “space navigation indicator.” It mercifully earned the nickname “Globus” at some point, understandable given the prominent mechanized globe the device features. Globus wasn’t actually linked to any kind of inertial navigation inputs, but rather was intended to provide cosmonauts with a visual indication of where their spacecraft was relative to the surface of the Earth. As such it depended on inputs from the cosmonauts, like an initial position and orbital altitude. From there, a complicated and absolutely gorgeous gear train featuring multiple differential gears advanced the globe, showing where the spacecraft currently was.

Those of you hoping for a complete teardown will be disappointed; the device, which bears evidence of coming from the time of the Apollo-Soyuz collaboration in 1975, is far too precious to be taken to bits, and certainly looks like it would put up a fight trying to get it back together. But [Ken] still manages to go into great depth, and reveals many of its secrets. Cool features include the geopolitically fixed orbital inclination; the ability to predict a landing point from a deorbit burn, also tinged with Cold War considerations; and the instrument’s limitations, like only supporting circular orbits, which prompted cosmonauts to call for its removal. But versions of Globus nonetheless appeared in pretty much everything the Soviets flew from 1961 to 2002. Talk about staying power!

Sure, the “glass cockpit” of modern space vehicles is more serviceable, but just for aesthetics alone, we think every crewed spacecraft should sport something like Globus. [Ken] did a great job reverse-engineering this, and we really appreciate the tour. And from the sound of it, [Curious Marc] had a hand in the effort, so maybe we’ll get a video too. Fingers crossed.

Thanks to [saintaardvark] for the tip.

Barely a week goes by without another hack blessing the RP2040 with a further interfacing superpower. This time it’s the turn of the humble PAL standard composite video interface. As many of us of at least a certain vintage will be familiar with, the Phase Alternate Line (PAL to friends) standard was used mainly in Europe (not France, they used SECAM like Russia, China, and co) and Australasia, and is a little different from the much earlier NTSC standard those in the US may fondly recollect. Anyway, [Fred] stresses that this hack isn’t for the faint-hearted, as the RP2040 needs one heck of an overclock (up to 312 MHz, some 241% over stock) to be able to pull off the needed amount of processing grunt. This is much more than yet another PIO hack.

The dual cores of the RP2040 are really being pushed here. The software is split into high and low-level functions, with the first core running rendering the various still images and video demos into a framebuffer. The second core runs in parallel and deals with all the nitty-gritty of formatting the frame buffer into a PAL-encoded signal, which is then sucked out by the DMA and pushed to the outside world via the PIO. There may be a few opportunities for speeding the code up even more, but [Fred] has clearly already done a huge amount of work there, just to get it working at all. The PIO code itself is very simple but is instructive as a good example of how to use multiple chained DMA channels to push data through the PIO at the fastest possible rate.

Beyond the Pico PCB, the only extra hardware needed was a resistor-ladder DAC implemented on a solderless breadboard. [Fred] needed a couple of goes to get the correct DAC resistor values, the first version was built on a small prototyping PCB, but unfortunately, the peak voltage was only 1 V, so it was necessary to build a second version (hence the breadboard) to get it to the correct 1.25 V.

We’ve covered video hacks on diminutive hardware many a time, even going into some details of the various standards, like this piece on just why is NTSC so odd? But as time marches on, video standards have gone through vast changes to get to where we are now.

via Adafruit.

When the first radios and telegraph lines were put into service, essentially the only way to communicate was to use Morse code. The first transmitters had extremely inefficient designs by today’s standards, so this was more a practical limitation than a choice. As the technology evolved there became less and less reason to use Morse to communicate, but plenty of amateur radio operators still use this mode including [Kevin] aka [KB9RLW] who has built a circuit which can translate spoken Morse code into a broadcasted Morse radio signal.

The circuit works by feeding the signal from a microphone into an Arduino. The Arduino listens for a certain threshold and keys the radio when it detects a word being spoken. Radio operators use the words “dit” and “dah” for dots and dashes respectively, and the Arduino isn’t really translating the words so much as it is sending a signal for the duration of however long each word takes to say. The software for the Arduino is provided on the project’s GitHub page as well, and uses a number of approaches to make sure the keyed signal is as clean as possible.

[Kevin] mentions that this device could be used by anyone who wishes to operate a radio in this mode who might have difficulty using a traditional Morse key and who doesn’t want to retrain their brain to use other available equipment like a puff straw or a foot key. The circuit is remarkably straightforward for what it does, and in the video below it seems [Kevin] is having a blast using it. If you’re still looking to learn to “speak” Morse code, though, take a look at this guide which goes into detail about it.

Thanks to [Dragan] for the tip!

It doesn’t happen often, but every once in a while we stumble upon someone who has taken obsolete but really cool phone-switching equipment and built a private switched telephone in their garage or basement using it. This private analog phone exchange is not one of those, but it’s still a super cool build that’s probably about as ambitious as getting an old step-by-step or crossbar switch running.

Right up front, we’ll stipulate that there’s absolutely no practical reason to do something like this. And hacker [Jon Petter Skagmo] admits that this is very much a “because I can” project. The idea is to support a bunch of old landline phones distributed around the house, and beyond, in a sort of glorified intercom system. The private exchange is entirely scratch-built, with a PIC32 acting as the heart of the system, performing such tasks as DTMF decoding, generating ring voltage, and even providing a CAN bus interface to his home automation system.

The main board supports five line interface daughterboards, which connect each phone to the switch via an RJ11 jack. The interface does the work of detecting when a phone goes off-hook, and does the actual connection between any two phones. A separate, special interface card provides an auto-patch capability using an RDA1846S RF transceiver module; with it, [Jon Petter] can connect to any phone in the system from a UHF handy-talkie. Check out the video below for more on that — it’s pretty neat!

We just love everything about this overengineered project — it’s clearly a labor of love, and the fit and finish really reflect that. And even though it’s not strictly old school, POTS projects like this always put us in the mood to watch the “Speedy Cutover” video one more time.

If you missed the Chumby, we’re sorry.  They were relatively inexpensive Linux appliances that acted as a clock, Internet radio, and feed reader. The company went belly up, although there was some functionality remaining thanks to one of the founders and now, for a subscription fee, you can still keep your Chumby operating. However, [Doug Brown] bought one with the goal of using it for his own applications. But the 2.6.28 kernel is showing its age. So he decided to push a new kernel on the device.

If you are a Chumby enthusiast, don’t get too excited. The goal isn’t to provide the existing Chumby apps with a new kernel, [Doug] says that’s probably impossible. Instead, he wants a modern booting infrastructure and kernel on the device for his own software.

The post is only part one, but it covers how he got U-Boot to load from an SD card. Given the success of that, we don’t think it will be long before the new kernel is running, too.

Understanding the boot process is a bit of arcane knowledge and [Doug] found back in 2013 that he didn’t quite understand it well enough to get the 3.13 kernel on the box, but now he’s ready to take the challenge and based on his work so far, we agree.

We were sad when Chumby stopped selling hardware. Chumby had white labeled the device to other companies, too, and we saw at least one of those driving a robot.

The HP-16C Computer Scientist is much beloved as the only dedicated programmer’s calculator that Hewlett-Packard ever made. Most surviving examples in the world are well-used, and you haven’t been able to order one from HP since 1989. Thus, [K Johansen] set about building a tribute to the HP-16C using modern hardware.

The build relies on a Raspberry Pi Pico as the brains of the operation. As with so many classic HP calculators, it operates in Reverse Polish Notation, and includes the customary stack operations. To serve a programmer well, it’s set up to accept entry in hexadecimal, octal, decimal, and binary formats, and can readily convert between them. Beyond that, it’s equipped with the usual arithmetic operators, as well as bitwise operations like NOT, AND, and so on.

Perhaps what we love most, though, is the keypad. It was all put together with a combination of cheap AliExpress keypads, a label maker, and a laser printer. It’s a wholly DIY job, and a little rough around the edges, but it makes the calculator far easier to use.

It’s not an exact replica of the HP-16C, but the differences in operation are minor.Those wishing to build their own can grab the required files from the project’s Github page. We’ve seen replicas of other classic HP calculators before, too. If you’ve got your own mathematical projects brewing up in the lab, don’t hesitate to send them in to the tipsline!

The original Ghostbusters movie is a classic that’s still delivering nearly 40 years after its release — just let that sink in for a minute. Almost every aspect of the film, from hand props to quotes, is instantly recognizable, even to people who haven’t based their lives on the teachings of [Venkman], [Stantz], and [Spengler]. To wit, we present this PKE meter-style WiFi scanner.

Of course, [Kevin McAleer]’s project is strictly in the “Just for Fun” category. But that doesn’t mean it’s not at least somewhat useful. The design is pretty close to the original PKE meter, with a little bit of creative license taken to make it easier to build. Guts include a Raspberry Pi Pico W and a generous 320×240 LCD display. The body of the meter is entirely 3D printed; design files are of course available. The meter’s arms are geared together to move with a single hobby servo.

On the software side, [Kevin]’s GUI lets users see a list of WiFi hotspots in the area and select one from the list. From there, the position of the arms is determined by the RSSI for the hotspot, similar to how the prop was supposed to indicate the proximity to a spook, specter, or ghost. There’s perhaps a bit of a missed opportunity by not adding LEDs to the arms, but we’ll let that slide.

The video below has full design and build details, but fair warning that it’s a bit on the long side. That’s probably just a reflection of how much work [Kevin] put into this, though. Of course, you may rather build a PKE meter that “actually” detects ghosts, in which case we’ve got you covered.

Often with more “modern” complex protocols involving handshaking, token exchanges, and all the other hoops and whistles accompanying them, we forget how useful and powerful serial can be. In what might be a wonderful tribute to that, [Davide Gironi] created a simple AVR-powered 16-digit serial display.

It can display two numbers, and that’s it. A MAX7219 drives the display, and the brains are an ATmega8. It’s straightforward to send new values: a start byte, a CRC, the data to display, and an end byte. A CP2102 provides a UART to USB interface to connect to a host. An EEPROM helps it remember the last numbers shown. It supports positive, negative, and floating-point numbers.

This is a beautiful example of doing one thing and doing it well. The design is simple and allows it to be used for anything. You can show the current stock market price, the time for the next two trains for your commute, or whatever else you can think of. [Davide] included a schematic, code, and a 3d printed enclosure.

Perhaps the idea could be combined with a clever design for a single-motor seven-segment display.

Over the last few years we have brought you many stories about John Deere tractors, and how their repair has been locked down such that only manufacturer-authorised technicians can work on them. They’ve become a poster child in the battle for the right to repair, a symbol of the worst practices. Finally now we can bring you some good news of sorts, as the agricultural giant has signed a memorandum of understanding with the American Farm Bureau Federation to ensure that their products will henceforth be repairable by people without Deere approval.

We can’t imagine that Deere will have taken this step willingly, and while we’d like to imagine that consumer protests in favour of right-to-repair have hit their mark, we’re guessing that it’s more of an economic pressure at work alongside the threat of legislation outside their native America. If farmers getting caught out waiting for a Deere van to arrive while their crop withers in the field wasn’t enough, when the price of a second-hand tractor without the DRM outstrips that of a newer one with it, eventually the sales of new tractors will also suffer.

So this is good news, and we’re guessing that other agricultural manufacturers doing the same DMCA practices will now follow suit. But it’s not a complete victory. The problem starts not with the DMCA restriction itself, but with the extension of the machine’s computer system into every part, including those many parts which simply don’t need it. It’s not a complete victory if anyone can now use the software to register a new hydraulic valve with the system; instead that hydraulic valve should not have to be authorised in the first place. It’s this creeping unnecessary complexity which is the true enemy of right-to-repair, and we shouldn’t forget that.

Header image: Dwight Sipler, CC BY 2.0.

If you’ve been pining for a retro-chic 16×2 LCD display to enhance your Windows computing experience, then [mircemk] has got you covered with their neat Windows-based LCD Info Panel.

Your everyday garden variety Arduino is the hero here, sitting between the computer’s USB port and the display to make the magic happen. Using the ‘LCD Smartie‘ software, the display can serve up some of your typical PC stats such as CPU and network utilization, storage capacity etc. It can also display information from BBC World News, email clients, various computer games and a world of other sources using plugins.

It’s clear that the intention here was to include the display inside your typical PC drive bay, but as you can see in the video below, this display can just about fit anywhere. It’s not uncommon to see similar displays on expensive ‘gamer’ peripherals, so this might be an inexpensive way for someone to bring that same LED-lit charm to their next PC build. You probably have these parts sitting in your desk drawer right now.

If you want to get started building your own, there’s more info over on the Hackaday.io page. And if PC notifications aren’t your jam, it’s worth remembering that these 16×2 displays are good for just about anything, like playing Space Invaders.

The CPU is the part of the computer that makes everything else tick. While GPUs have increasingly become a key part of overall system performance, we still find ourselves wanting to know how our CPU is doing. CoreFreq is a Linux tool that aims to tell you everything you want to know about your modern 64-bit CPU.

The tool relies on a kernel module, and is coded primarily in C, with some assembly code used to measure performance as accurately as possible. It’s capable of reporting everything from core frequencies to details on hyper-threading and turbo boost operation. Other performance reports include information on instructions per cycle or instructions per second, and of course, all the thermal monitoring data you could ask for. It all runs in the terminal, which helps keep overheads low.

The hardcore among us can build it from source, available on GitHub, though it’s reportedly available in package form, and as a live CD, too. We could imagine data captured from CoreFreq could be used for some fun performance visualizations, too. If you’ve been whipping up your own nifty command-line tools, be sure to drop us a line!

If you are a certain age, you probably remember the Mattel Football game. No LCD screen or fancy cartridges. Just some LEDs and a way to play football when you should be in class. While these might seem primitive to today’s kids, they were marvels of technology in the 1970s when they came out. [Sean Riddle] looks, well, not exactly at the games, but more like in them. As it turns out, they used chips derived from those made for calculators.

[Sean’s] post is a glimpse into this world of over four decades past. Football was actually the second electronic game from Mattel. The first one was Auto Race. There were also games called Space Alert, Baseball, and Gravity. Inside each are quad in-line packages with 42 pins, a Rockwell logo, and a custom part number.

The analysis led [Sean] to buy several games along with Rockwell calculators and microcontrollers. By decapping the ICs in each, he was able to note the similarities and differences between the old processors. There were also patent filings that had key information, along with donated source and object code and an interview with the designer of several of the games.

In a classic case of a bad computer model, Mattel made 100,000 Football games which were sold by Sears and Roebuck. Sears sold a few and used a computer model to predict that Football and Auto Race would not be big sellers, so production stopped. However, the game was a runaway success, selling up to 500,000 units a week, according to the article in the Handheld Museum.

If you haven’t had the pleasure of seeing a state-of-the-art 1977 Football game, check out the video from [The Retro Future] below. Mattel even made a personal computer back in the day. Milton Bradley was in the game, too, with their programmable Big Trak.

[Ted Fried] wrote in with not one but two (2!) new drop-in replacements for widespread old-school CPUs: the Zilog Z80 and the Intel 8088. Both of the “chips” run in cycle-accurate mode as well as in a super turbo mode, which can run so fast that you’ll need to use the Teensy’s internal RAM just to keep up.

Both of these designs have a hardware and software component. The PCBs basically adapt the pinout of the Teensy to the target CPU, with a bunch of 74VLC latches on board to do the voltage level conversion. The rest is a matter of emulating all of the instructions on the Teensy, which is more than fast enough to keep up. If this sounds familiar to you, it’s basically the same approach that [Ted] used last year to bring us his replacement for the 6502 found in the Apple ][ and Commodore 64.

Why would you want an emulated CPU when the originals are still available? [Ted] inherited a busted Osborne I, an ancient Z80 luggable. By replacing the original Z80 with his emulation, he could diagnose the entire system, which led him to discover some bad DRAM chips and get the old beast running again. Or maybe you just want to play IBM XT games at insane speeds?

And it looks like [Ted] has updated his 6502 emulation to include the undocumented C64 opcodes, so if you’re into that scene, you should be covered as well.

If any of this tickles your fancy, head over to [Ted]’s blog, microcore labs, and follow along. Although now that he’s covered most of the famous retrocomputers, we have to ask ourselves what processor is going to be next?

Historically, one of the nice things about Unix and Linux is that everything is a file, and files are just sequences of characters. Of course, modern practice is that everything is not a file, and there is a proliferation of files with some imposed structure. However, if you’ve ever worked on old systems where your file access was by the block, you’ll appreciate the Unix-like files. Classic tools like awk, sed, and grep work with this idea. Files are just characters. But this sometimes has its problems. That’s the motivation behind a tool called Miller, and I think it deserves more attention because, for certain tasks, it is a lifesaver.

The Problem

Consider trying to process a comma-delimited file, known as a CSV file. There are a lot of variations to this type of file. Here’s one that defines two “columns.” I’ve deliberately used different line formats as a test, but most often, you get one format for the entire file:

Slot,String 
A,"Hello" 
"B",Howdy 
"C","Hello Hackaday" 
"D","""Madam, I'm Adam,"" he said." 
E 100,With some spaces!
X,"With a comma, or two, even"

The first column, Slot, has items A, B, C, D, and E 100. Note that some of the items are quoted, but others are not. In any event, the column content is B not “B” because the quotes are not part of the data.

The second column, String, has a mix of quotes, no quotes, spaces, and even commas inside quotes. Suppose you wanted to process this with awk. You can do it, but it is painful. Notice the quotes are escaped using double quotes, as is the custom in CSV files. Writing a regular expression to break that up is not impossible but painful. That’s where Miller comes in. It knows about data formats like CSV, JSON, KDVP8, and a few others. It can also output in those formats and others like Markdown, for example.

Simple Example Runs

Because it knows about the format, it can process the file handily:

$ mlr –icsv cat miller.in
Slot=A,String=Hello
Slot=B,String=Howdy
Slot=C,String=Hello Hackaday
Slot=D,String=”Madam, I’m Adam,” he said.
Slot=E 100,String=With some spaces!
Slot=X,String=With a comma, or two, even

Notice there is no command called “miller.” The command name is “mlr.” This output wouldn’t be a bad format to further process with awk, but we don’t have to. Miller can probably do everything we need. Before we look at that, though, consider what would happen if you just wanted a pretty format output:

Not too bad! Don’t forget, the tool would do the same trick with JSON and other formats, too.

So Many Options

The number of options can be daunting. There are options to pass or ignore comments, process compressed data, or customize the input or output file format a bit.

But the real power to Miller is the verbs. In the above example, the verb was cat. These are mostly named after the Linux commands they duplicate. For example, cut will remove certain fields from the data. The grep, head, and tail commands all do what you expect.

There are many new verbs, too. Count will give you a count of how much data has gone by and filter is a better version of grep. You can do database-like joins, sorting, and even statistics and generate text-based bar graphs.

The filter and put commands have an entire programming language at their disposal that has all the things you’d expect to find in a language like awk or Perl.

What’s nice is that when you want to remove a field or sort, you can refer to it by name (like “Slot”), and Miller will know what you mean. There is a way to refer to fields with numbers if you must, but that’s a rare thing in a Miller script.

For example, if you have some data with fields “stock” and “reserve” that you want to get rid of, you could write something like this:

mlr --icsv --opprint cut -f stock,reserve inventory.csv

Or, perhaps you want to select lines where stock is “N”:

mlr --icsv --opprint filter '$stock == "N"' inventory.csv

Go Read

There’s simply not enough room to cover all the features of this powerful program. I’d suggest you check out Miller in 10 Minutes which is part of the official documentation. You’ll still need to read the documentation further, but at least you’ll have a good start.

Don’t get me wrong, we still like awk. With a little work, you can make it do almost anything. But if you can do less work with Miller, why not?

Folks from [Adafruit] are showing off a neat hack – USB host on RP2040, using the now-famous PIO peripheral. [Adafruit] builds a lot of RP2040 boards, and naturally, you gotta test them before you ship them to customers. They’ve been using very specific Teensies for that, and at some point, those became unobtainium. Based on the work of [sekigon-gonnoc] and with help of [Thach], they’ve made their TinyUSB library support bitbanging of USB over PIO, and successfully ported their test jig firmware to it!

The base Pico-PIO-USB repo by [sekigon-gonnoc] shows a pretty impressive state of affairs – with low-speed and full-speed USB host and full-speed USB device modes supported, and quite a few examples to get you started. [Adafruit]’s work integrates this code into their TinyUSB stack, specifically focusing on MST (mass storage) features – as this is what you need to program a RP2040. Of course, they also provide a mass storage example to boot!

Test jigs are pretty important to have when making multiple pieces of a board, and with RP2040 supporting more and more interfaces thanks to PIO, it sounds like the perfect chip for your next production testing-intended PCB. With the jig brains taken care of, you’ll want to look into building no less important mechanical part, and we’ve covered quite a few ways to sort that out – here’s an OpenSCAD script that generates lasercutting files out of KiCad boards, or a jig built out of scrap copperclad FR4, and a pretty extensive tutorial on making your own lasercuttable jigs, to boot.

The modern TV news studio is a masterpiece of live video and CGI, as networks vie for the flashiest presentation. BBC News in London is no exception, and embraced the future in 2013 to the extent of replacing its flesh-and-blood camera operators with robotic cameras. On the face of it this made sense; it was cheaper, and newsroom cameras are most likely to record as set range of very similar shots. A decade later they’re to be retired in a victory for humans, as the corporation tires of the stream of viral fails leaving presenters scrambling to catch up.

A media story might seem slim pickings for Hackaday readers, however there’s food for thought in there for the technically minded. It seems the cameras had a set of pre-programmed maneuvers which the production teams could select for their different shots, and it was too easy for the wrong one to be enabled. There’s also a suggestion that the age of the system might have something to do with it, but this is somewhat undermined by their example which we’ve placed below being from when the cameras were only a year old.

Given that a modern TV studio is a tightly controlled space and that detecting the location of the presenter plus whether they are in shot or not should not have been out of reach in 2013, so we’re left curious as to why they haven’t taken this route. Perhaps OpenCV to detect a human, or simply detecting the audio levels on the microphones before committing to a move could do the job. Either way we welcome the camera operators back even if we never see them, though we’ll miss the viral funnies.

If you were ever looking for a small relaxing evening project that you could then use day-to-day, you gotta consider the Pico Hat Pad kit by [Natalie the Nerd]. It fits squarely within the Pi Pico form-factor, giving you two buttons, one rotary encoder and two individually addressable LEDs to play with. Initially, this macropad was intended as an under-$20 device that’s also a soldering practice kit, and [Natalie] has knocked it out of the park.

You build this macropad out of a stack of three PCBs — the middle one connecting the Pi Pico heart to the buttons, encoders and LEDs, and the remaining ones adding structural support and protection. All the PCBs fit together into a neat tab-connected panel — ready to be thrown into your favorite PCB service’s shopping cart. Under the hood, this macropad uses KMK, a CircuitPython-based keyboard firmware, with the configuration open-source. In fact everything is open-source, just the way we like it.

If you find yourself with an unexpected affinity for macropads after assembling this one, don’t panic. It’s quite a common side-effect. Fortunately, there are cures, and it’s no longer inevitable that you’ll go bananas about it. That said, if you’re fighting the urges to go bigger, you can try a different hand-wireable Pico-based macropad with three more keys. Come to find that one not enough? Here’s a 2×4 3D printable one.

Now, if you eventually find yourself reading every single Keebin’ With Kristina episode as soon as it comes out, you might be too far gone, and we’ll soon find you spending hundreds of dollars building tiny OLED screens into individual keys — in which case, make sure you document it and share it with us!

You don’t always need much to build an FPV rig – especially if you’re willing to take advantage of the power of modern smartphones. [joe57005] is showing off his VR FPV build – a fully-printable small Mechanum wheels car chassis, equipped with an ESP32-CAM board serving a 720×720 stream through WiFi. The car uses regular 9g servos to drive each wheel, giving you omnidirectional movement wherever you want to go. An ESP32 CPU and a single low-res camera might not sound like much if you’re aiming for a VR view, and all the ESP32 does is stream the video feed over WebSockets – however, the simplicity is well-compensated for on the frontend.

The software stack, served as client-side JavaScript by the ESP32, is what makes this elegant build shine. [joe57005] uses Samsung Gear VR for the projects, a cheap but decent-quality “smartphone holder” VR headset. The ESP32’s camera feed is converted into a faux 3D VR image inside the smartphone’s web browser, using the technology called WebXR , with image de-warping using WebGL, and vanilla JavaScript straightforward touch controls for the HUD. All is open-source and public, and 3D printing files are soon to come to Printables – for now, we get the FreeCad source, which is more than good enough.

If you wanted a self-sufficient FPV platform you could play with, check this one out – it’s seriously accessible, software effort put in is worth learning from, and if you ever wanted to try WebXR, the code provided ought to be a nice playground. It reminds us of an another cute ESP32-driven FPV bot that we’ve seen a few years ago.

Got an FPV idea in mind? We’d like to see it, and we have a contest for that too! Don’t delay bringing it to life!

Video effects and mixing are done digitally today, but it wasn’t always so. When analog ruled the video world, a big switch panel was key to effective results.

Devices like [Glen]’s Grass Valley Series 300 Crosspoint Switch Panel were an important part of that world. With tools like that, a human operator could set up a composited preview feed in true WYSIWYG style, and switch to live on cue. All done with relatively simple CMOS ICs and buttons. Lots and lots of buttons.

[Glen] reverse engineers the panel to show how it works, and most of the heavy lifting is done by the MC14051B analog multiplexer/demultiplexer, and the MC14532B 8-bit priority encoder. Once that’s figured out, the door is open to modernizing things a little by using a microcontroller to drive the device, turning it into a USB peripheral.

With a little design work, [Glen] builds a PCB around the EFM8UB2 8-bit microcontroller to act as a USB peripheral and control the switch panel, taking care of things like key scanning and lamp control. The last step: a GUI application for monitoring and controlling the panel over USB.

This isn’t [Glen]’s first time interfacing to vintage video mixing and switching, and as many of us know it’s sometimes tricky work to interface to existing hardware. We covered his earlier video switcher project using hardware that was not nearly as easy to work with as this one.

Between 1976 and 1978, over one million Coleco Telstar video game consoles were sold. The Killer App that made them so desirable? PONG. Yep, those two paddles bouncing a ball around a blocky tennis court were all the rage and helped usher in a new era. And as [Dave] of Dave’s Garage shows us in the video below the break, the bringing the old console back to life proved simpler than expected!

Thankfully, the console is built around what [Dave] quite aptly calls “PONG on a chip”, the General Instrument AY-3-8500 which was designed to make mass production of consoles possible. The chip actually contains several games, although PONG was the only one in use on the Coleco.

After removing the CPU from the non-functional console, [Dave] breathed life into it by providing a 2 MHz clock signal that was generated by an Arduino, of all things. A typical 2N2222 amplifies the audio, and a quick power up showed that the chip was working and generating audio.

Video is smartly taken care of just as it was in the original design, by combining various signals with a 4072 OR gate. With various video elements and synchronization patterns combined into a composite video signal, [Dave] was able to see the game on screen, but then realized that he’d need to design some “paddles”. We’ll leave that up to you to watch in the video, but make sure to check the comments section for more information on the design.

Is a breadboarded PONG console not retro enough for you? Then check out this old school mechanical version that was found languishing in a thrift store.

While we have all types of displays these days, there’s something special about those that appear to float in the air. This HUD clock from [Kiwi Bushwalker] is one such example.

The build relies on four 8×8 LED matrixes to display the four digits that make up the time, run by the MAX7219 driver chip. However, the LEDs aren’t viewed directly — that would be too simple. Instead, the matrixes shoot their light up at an angle towards a tilted piece of clear acrylic. This creates a “heads-up display” look where the numbers appear to float in the air.  The clock gets accurate time from an NTP time server over WiFi, thanks to the ESP32 microcontroller that runs the show.

It’s a straightforward clock build in many ways, but we particularly like the use of the heads-up display technique. It’s almost surprising we don’t see these projects more often, for things like car dashboard displays or targeting womp rats in a T-16 landspeeder. If you’ve been whipping up your own HUD projects, don’t hesitate to notify the tipsline!

The recent flurry of videos and posts about the TVGuardian foul language filter brought back some fond memories. I was the chief engineer on this project for most of its lifespan. You’ve watched the teardowns, you’ve seen the reverse engineering, now here’s the inside scoop.

Gumby is Born

Back in 1999, my company took on a redesign project for the TVG product, a box that replaced curse words in closed-captioning with sanitized equivalents. Our first task was to take an existing design that had been produced in limited volumes and improve it to be more easily manufactured.

The original PCB used all thru-hole components and didn’t scale well to large quantity production. Replacing the parts with their surface mount equivalents resulted in Model 101, internally named Gumby for reasons long lost. If you have a sharp eye, you will have noticed something odd about two parts on the board as shown in [Ben Eater]’s video. The Microchip PIC and the Zilog OSD chip had two overlapping footprints, one for thru-hole and one for SMD. Even though we preferred SMD parts, sometimes there were supply issues. This was a technique we used on several designs in our company to hedge our bets. It also allowed us to use a socketed ICs for testing and development.

The Model 101 case received some jabs in the video, and deservedly so. The case mold was made before my involvement, but the original prototype we received was in a box that was too expensive to use in production, and it had a locking door on the back which ostensibly prevented one from unplugging the cables. At the time, our client had licensed at least one other flavor of the box called Curse Free TV ([foone] obtained one of those in their collection), and this required a mold insert to change the branding. I can’t remember the details of why there was the unused RF input, but it was either a regulatory requirement or just a consequence available modules on the market in the 1990s. My colleague fashioned a unique version for travel that was flat (without the RF modulator). We called it “Gumby Light”.

One non-obvious thing I’d like to mention about the Zilog Z86129 CC/OSD chip is that it was only half-used. The ‘129 was made to work as a stand-alone CC processor, and had no provision to access to the decoded CC data stream. Gumby’s design completely ignored this half of the chip, and used the ‘129 as an OSD generator only. Instead, the original designers thresholded line 21 data and shifted it into the PIC using really clever/evil assembly language. There were 96 pairs of bit test / bit set instructions, each executing in the same amount of time regardless of whether the CC data slicer comparator was high or low.

As [Alec] pointed out in his video, there was a switch that turned off filtering, changing the box into an external CC decoder. There was a minor demand for this functionality during all the years these products were sold, and all the designs retained this capability. Despite the FCC mandate for all new TVs to have a built-in closed caption decoder, some viewers with older or small TV sets still wanted captions and ordered these models just for that purpose.

Foul Language Dictionary

When I watched [Ben Eater] start to connect up the serial EEPROM to pull out the curse words, I was reminded of a funny incident during the production ramp-up of Gumby. The manufacturer asked to approve an alternate supplier for this EEPROM. After I checked the data sheet and a few samples, I authorized the request. Soon afterwards, they came back with a mysterious failure. We quickly tracked the problem down to the EEPROM, and realized that the data was all scrambled. But strangely, I could reprogram it and it worked fine. I clearly remember a phone call with a lady from the service company that we used to program the chips. They were following the correct procedure, getting the correct checksums, and we were baffled. There was a long pause, and she suddenly broke the silence,

“You know, it’s none of my business, but there are a some really bad words here in your hex file”.

In response to that incident, I implemented a cursory scrambling of the text, not for encryption, but so someone casually browsing the data wouldn’t be hit by a screenful of cussing. Alas, the unit [Ben] dismantled was manufactured before this.

We did ultimately find the problem with the EEPROM. The substitute had a block programming mode that put the contents into memory in a different sequence than the Microchip 93LC86 did. This was not implemented in all chip programmers, nor documented in the data sheet, but was discovered upon requesting further programming documents from the manufacturer.

Daisy and Oliver

Once Gumby production was underway, the search was on for a new design that could handle new features, expanded I/O options like S-Video, digital audio, and multiple inputs. This turned out to be much more challenging than anyone thought. While chip manufacturers had various options for handling CC, they were focusing their efforts on digital video. It was clear that analog CC was on the decline. The Zilog ‘129 and its sister chips were very tempting contenders. At heart, they were really a DSP / microprocessor with custom masked-ROM firmware. We explored the option of using that in a new design with modified firmware. Gaining Zilog’s cooperation was tough, and when we learned the chip’s ROM was already filled to capacity, we gave up on that approach.

We finally stumbled on the Painter chip by Philips Semiconductor that was too good to pass up. It was a complete MCU (8051) with all the CC circuitry built-in and came with libraries for CC and user menu OSD. I wrote about this chip in my previous article on analog Closed Captions. Despite being told the part was “secret”, we eventually got permission to use it. This was my first, but sadly not last, encounter with the concept of a part and its support being so complicated that the manufacturer is very selective about who they can use it. Despite this hurdle, the team at Philips were great to work with. The Painter design formed the basis of three set top box models:

• Model 201 Oliver (2004)
• Model 301 Daisy (2004)
• Model 401 Oscar (2010)

The Oliver and Daisy designs, names also of unknown origin, were both based on the Painter chip, but with differing number of inputs. Daisy only had one and Oliver had two. Digital audio turned out to be easy to mute. It was no different than muting analog audio, except using different connectors. In both cases, audio being muted by interrupting the signal with a CMOS 4066 analog switch. Originally both designs used a single board, but our contract manufacturer requested a two-board solution to save costs. The connectors were mounted on a single-sided FR1 board, and therefore the main four-layer FR4 board was able to be smaller. It surprised us that adding the inter-board connectors and the extra processing was cheaper, but that’s the way the numbers added up.

That case mold insert came in handy for the Daisy version, since we could used that area for a membrane keypad overlay. Oscar, just another name starting with the same letter as Oliver, wraps up the analog series of set top boxes. It was just a PCB re-spin, made years later in 2010, using a different enclosure and probably the very last inventory in the world of Painter chips.

Macrovision

As good as it was, the Painter solution had a few issues in a set top box application. It was designed to exist inside a TV set, and required stable horizontal and vertical sync signals. We had to make this external to the chip. This would normally be a straightforward design but was complicated by the need to tolerate Macrovision’s Analog Copy Protection (ACP) scheme of the day. ACP existed in various flavors, all of them inserted extra sync pulses of varying amplitude in the vertical blanking interval (VBI) of the video. Ostensibly, these pulses wouldn’t mess with the high-Q tank synchronization circuit of a television set, but caused havoc on the sync and AGC circuits of VHS recorders. The PIC design we inherited in Gumby tolerated Macrovision in firmware, but wasn’t perfect. This worried me, because ACP methods were numerous and subject to change. I didn’t want to test against all different forms that the set top boxes might encounter in the field. So I chickened out on this part of the circuit design and bought a solution off-the-shelf in the form of the Elantec (now Renesas) EL1883 sync separator chip, passing the buck as it were.

A second but minor issue was that like the Zilog chip, normal CC module usage was as a stand-alone black box with no access to read / modify the data stream. But this being implemented in firmware, it was easy to hack around. We were able to grab and alter the data before presenting it to the CC decoder function.

The Painter support firmware provided by Philips was not entirely pre-compiled libraries. There were some aspects of the build that required re-compilation of certain proprietary source code files, depending on features needed by the application. Philips provided these files as encrypted source code and a decryption tool in the form of a Windows DLL named C51_RD.dll. They cooperated with Keil so that the compiler knew to make use of this decryption algorithm whenever a file with an .ec extension was encountered. I presume this ability must no longer be part of Keil, since I cannot find any mention of it online in 2022.

On the Trailing Edge

While the ‘1883 solved the Macrovision problem, there was one hiccup. The leading edge of the VSYNC signal was precisely specified, but the falling edge was not — in other words, the pulsewidth of VSYNC was not controlled. In fact, it varied quite a bit from chip to chip. This was not good, because the Painter’s CC decoding synchronized on the trailing edge of VSYNC. It turned out that the pulse width could be tweaked by changing the value of an external resistor Rset.

We dealt with this by adding a factory calibration step. The Painter would measure and display VSYNC pulse width the operator, and the operator would adjust the width up and down using two test fixture buttons until the pulse width reached the desired value, the Painter changing the effective Rset value using a PWM output. We collected over a thousand of these settings during the first production in 2004 in order to characterize the spread, both out of curiosity and at Elantec engineering’s request.

Fully Digital? Project Herbert

The set top box design remained stable for many years and the project eventually wound down. The advent of digital television and video made the technology in these units obsolete. Or so I thought. In 2010, I was asked to undertake a new design using HDMI video. The TVGuardian inventor [Rick Bray] had discovered that most HDMI video sources continued to provide simultaneous analog composite video output with the CC signal. Thus began the design of a new set top box I named Herbert — a random name starting with an “H” standing for HD video.

Entering the world of HDMI video designs is not for the faint-hearted. The entry price is painful, with steep annual membership required in both the HDMI and HDCP organizations along with per-unit royalties — those were in fact actually reasonable. None of the available HDMI chips had support for CC, since there is no CC data transmitted over the HDMI interface, a point I discussed in this article. We eventually selected the ADV7623 from Analog Devices, an HDMI repeater chip with support for OSD text and icons. This was one of those parts that came with the promise of minimal or no support from the manufacturer, especially since I was trying to use it in a way it wasn’t intended — that is, dynamically changing text instead of fixed OSD.

The Analog Devices engineers turned out to more helpful that we expected. While it was a long and frustrating hack, I eventually figured out the various hidden and undefined behaviors of the OSD system and made it work. Besides the original goal of making a CC decoder, another client in Korea wanted to use this chip to generate a scrolling text crawl along the bottom of the screen. Naturally, he wanted both English and Korean text (Hangul). That was another fun hack as well, generating foreign language glyphs and moving them smoothly one pixel at a time across the screen. The Herbert platform supported the TVG Model 501 product, and a few other niche applications that needed dynamic OSD overlay on HDMI.

Not a Telephone Jack

One interesting accessory I designed, but was never sold, was a center-channel audio muting switch for use with surround sound systems. There is an 6P6C modular connector on the back of Herbert providing auxiliary power and muting signals for this accessory. The idea here is that 95% of movie dialog comes in the center channel speaker, and the mute is less jarring when only the words are muted and other background sounds are preserved. I avoided needing to decode, tinker with, and re-encode the surround sound signals by just switching the wires going to the center-channel speaker. However, this was a pretty expensive module — it used relays to mute the audio, and switched in 8-ohm power resistors when muting in order to trick the amplifier into thinking the speaker was still connected. Otherwise, some amplifiers would sense a fault and shut down.

“Wow You” and “Oh Crud”

Factory testing needed a long repeatable source of closed captioning which included filthy words. In the very beginning, the factory used VHS copies of South Park animated sitcoms. Later on, I experimented with various custom VHS tapes, DVD movies, and even a computer with dual CC generator cards installed. I finally settled on making two custom DVDs. These had a video color bar test pattern and line 21 data containing words that alternated between cussing and not. These are the WOW YOU and OH CRUD test discs — two different discs/phrases were used so the operator could distinguish channel 1 from channel 2. A full setup for testing Herbert input used two DVD/BD players providing HDMI video, and two DVD players containing the CC discs generating the composite video. For outputs, a monitor was used to check the HDMI output, an oscilloscope with an optical to coaxial digital adaptor was used to check the muting, and a pair of LEDs were used to check the never-used auxiliary connector.

Bunny and Project Sally

All these experiences with closed designs and specialty chips really bothered me, and I continued searching for alternatives. On the HDMI side, I was really interested in applying the techniques developed by [Bunnie Huang] for NeTV, which we covered back in 2012. I experimented with his development kit, but alas I could not convince any of our clients to take the perceived legal risk of using his approach in a product.

I had more success with an internal design I called Sally — boringly named because “S” stood for for SD video. I was inspired by various Arm-based projects which were generating VGA signals directly for retro games. But it seemed to me that these wasted a lot of memory storing with pixel buffers. Then one day I realized that a timer-counter register could serve as the destination for a DMA transfer (on an LPC1768 at least). This meant you could store pixel data much more efficiently in a run-length encoding manner. A line of pixels was just a short buffer of amplitudes and timer durations. I built and demonstrated this approach, successfully generating test video patterns or CC signals. It could also synchronize with an incoming video signal for doing overlay of menus and CC data. Alas, this design never made it into production, but I may revisit this in a future writeup.

Recent Videos and Posts about TVGuardian

• [Alec Watson]’s Technology Connections video “This TV gadget censors bad words with 1980’s tech”
• [Ben Eater]’s follow-on video entitled “Hacking a weird TV censoring device”, which we covered here
• [RetroStuff]’s post “TVGuardian 101 and 201 Foul Language Filters” (actually from last year)
• [foone]’s extensive experiments with various TVG models

[Smbakeryt] needs your help. He bought a 1984-vintage Z8000 coprocessor card for the PC, but the software is missing in action. Apparently, the co-processor — called a Trump Card — appeared in Byte magazine courtesy of the famous [Steve Ciarcia]. The schematics were published, and if you sent [Steve] proof that you built it, he’d send you the software. The product was later commercialized, but no one seems to have the software, so [Smbakeryt] is on the lookout for it.

The board itself was pretty amazing for its day. It added a 16-bit Zilog Z8000 CPU with 512 K of RAM. Big iron for 1984 and a good bit more performance than a stock IBM PC of the era.

We miss the days when computer gear came with big binders of documentation. These days, you are more likely to get a sticker with a URL. The Z8000 was a nice processor and could emulate the Z80, but it never became hugely popular. In addition to Zilog’s System 8000, the CPU found its way into some Unix computers including the Onyx C8002 and several Olivetti computers. Commodore planned to use the CPU in a canceled project. The Z8000 was famous for not using microcode and, thus, it fit on a relatively small die with 17,500 transistors (compared to the 8086’s 29,000 transistors).

We hope someone can help out with the software. If you want your own Z8000 system, you might be better off with Clover. Or, stick with a Z80 on the cheap.

For a large part of the 20th century, motion pictures were distributed on nitrate film. Although cheaper for the studios, this film was highly flammable and prone to decay. On top of that, most film prints were simply discarded once they had been through their run at the cinema, so a lot of film history has been lost.

Sometimes, the rolls of projected film would be kept by the projectionist and eventually found by a collector. If the film was too badly damaged to project again, it might still get tossed. Pushing against this tide of decay and destruction are small groups of experts who scan and restore these films for the digital age.

The process is quite involved – starting with checking every single frame of film by hand and repairing any damaged perforations or splices that could come apart in the scanner. Each frame is then automatically scanned at up to 10K resolution to future-proof the process before being painstakingly digitally cleaned.

The real expertise is in knowing what is damage or dirt, and what is the character of the original film. Especially in stop-motion movies, the subtle changes between frames are really part of the original, so the automatic clean-up tools need to be selectively reined in so as not to lose the charm and art of the film-makers.

The results are quite astonishing and we all have teams like this to thank for protecting our cultural heritage.

If you’re interested in watching the process, then check out the video after the break. If you fancy a go at automatic film digitising yourself (preferably not on unique historical prints!) then we’ve shown projects to do just that in the past.

Thanks to [Cliff Claven] for the tip.

It’s always great when we get a chance to follow up on a previous project with more information, or further developments. So we’re happy that [“Ancient” James Brown] just dropped a new video showing the assembly of his Lego brick with a tiny OLED screen inside it. The readers are too, apparently — we got at least half a dozen tips on this one.

We’ve got to admit that this one’s a real treat, with a host of interesting skills on display. Our previous coverage on these bedazzled bricks was disappointingly thin on details, and now the original tweets even seem to have disappeared entirely. In case you didn’t catch the original post, [James] found a way to embed a microcontroller and a remarkably small OLED screen into a Lego-compatible brick — technically a “slope 45 2×2, #3039” — that does a great job of standing in for a tiny computer monitor.

The present video shares a lot more detail on this fancy brick. The core of the circuit is four tiny scraps of PCB, hosting the RP2040 microcontroller and necessary support components. [James] used a series of 3D-printed jigs to hold the boards while soldering, which results in a compact package to fit inside the sloped brick. After attaching the diminutive OLED and doing a little testing, the circuit origami is placed into one half of a two-piece silicone mold. Translucent plastic resin is mixed up and added to the mold, which flows around the circuit to complete the build.

The results are amazing — a brick that looks like a stock Lego part, at least until it’s plugged into a powered baseplate. The way the screen is molded right into the resin and shines right through it is enchanting, and the texture on the face of the slope looks fantastic. We’re mightily impressed by the craftsmanship here, and we’re very glad [James] shared the details of his process. Now if we could only get build files…

Thanks to [Footleg], [DKE], and a bunch of other people for this tip!

Archiving data from old storage media can be a highly complex process. It can be as simple as putting a disk in an old drive and reading out the contents. These days, though, the state of the art is more complex, with advanced techniques helping to recover the most data possible. The VHS-Decode project is an effort to improve the archiving of old analog video tapes.

The project is a fork of the LaserDisc-focused ld-decode, started by [Chad Page] back in 2013, which readers may recall was used for the Domesday Duplicator — a device aimed to recover data from the BBC’s ancient Domesday LaserDiscs. VHS-Decode is designed to capture the raw RF signals straight out of a tape head, which are the most direct representation of the signals on the physical media. From there, these signals can be processed in various ways to best recover the original audio and video tracks. It’s much the same technique as is used by floppy disk recovery tools like the FluxEngine.

Despite the VHS name, the code currently works with several tape formats. VHS, S-VHS and U-Matic are supported in PAL and NTSC formats, while Betamax, Video8 and High8 tape capture remains a work in progress. Using the code requires a video tape player with test points or traces that make signals from the head accessible. Capturing those signals is achieved via a Domesday Duplicator hardware device, or alternatively a Conexant CX2388x analog-to-digital converter, often found in many old PCI TV tuner cards. Various techniques can then be used to turn the captured signals into watchable video files.

We love a good archival project, and VHS-Decode is clearly a useful tool when it comes to salvaging old video tapes.

[Thanks to JohnU for the tip!]

We feature a lot of clocks here at Hackaday, but alarm clocks seem to be less popular for some reason. Maybe that’s because no-one enjoys being woken up in the morning, or simply because everyone uses their smartphone for that purpose already. In any case, we’re delighted to bring you [Manuel Tosone]’s beautiful Nixie tube alarm clock that cleverly combines modern and classic technologies in a single package.

The clock and alarm functionalities are implemented by a PIC24 microcontroller on a custom mainboard. It keeps track of time through its real-time clock with battery backup, and plays a song from an SD card when it’s time to wake up. A 2 x 3 W class D audio amplifier plus a pair of stereo speakers should be able to wake even the heaviest sleepers.

Of course, the real party piece is the clock’s display: four IN-4 Nixie tubes show the time, with neon tubes indicating the day of the week. The 180 V needed for the Nixies is generated by an MC34063A-based boost converter, which also powers the neon tubes.

Instead of using the standard current-limiting resistor for each Nixie tube, [Manuel] designed an array of transistor-based current sources: this enables linear control of the tubes’ brightness, and should keep the amount of light constant even as the tubes age. The individual segments are switched by SN75468 Darlington arrays, with no need for those hard-to-find SN74141 drivers.

The mainboard and the display are housed inside a 3D-printed case that mimics the style of 1980s digital alarm clocks, but with a nice 1970s twist courtesy of those Nixie tubes. [Manuel]’s GitHub page has all the schematics as well as extensive documentation describing the circuit’s operation — an excellent resource if you’re planning to build a Nixie project yourself. If Nixies aren’t your thing, you can also make an alarm clock with a VFD tube, or even roll your own luminous analog dial.

As a programming language, Lisp has been around longer than any other active language except for Fortran. To anyone who regularly uses it, it’s easy to see why: the language allows for new syntax and macros to be created fluidly, which makes it easy to adapt it to new situations, like running it on a modern Atmel microcontroller to control the LEDs on this star pendant.

The pendant has simple enough hardware — six LEDs arranged around the points of the star, all being driven by a small ATtiny3227 operating from a coin cell battery. This isn’t especially spectacular on it’s own, but this particular microcontroller is running an integer version of a custom-built Lisp interpreter called uLisp. The project’s creator did this simply because of the whimsy involved in running a high-level programming language on one of the smallest microcontrollers around that would actually support the limited functionality of this version of Lisp. This implementation does stretch the memory and processing capabilities of the microcontroller quite a bit, but with some concessions, it’s able to run everything without issue.

As far as this project goes, it’s impressive if for nothing other than the ‘I climbed the mountain because it was there’ attitude. We appreciate all kinds of projects in that same vein, like this Arduino competitor which supports a programming language with only eight commands, or this drone which can carry a human.

[Zak]’s two-floor apartment has a typical door entry control system, but the setup is less than ideally convenient. The wall-mounted telephone-like intercom is downstairs, but [Zak] is usually upstairs. What’s an enterprising hacker to do? Obviously the most elegant solution is to simply do without visitors in the first place, but [Zak] opted for a more full-featured solution to the problem.

He fixed things with a custom ESP8285-based board that, with the help of opto-isolation, allows him to detect visitors and grant entry without having to be physically present at the wall-mounted intercom. It’s even integrated into Telegram, and has a few neat new features. Let’s take a look.

The first interesting bit is how [Zak] rolled his own opto-isolation. The door entry system uses 14 VAC and is frankly — electromagnetically-speaking — a very noisy device. Attaching GPIO pins directly to this system from the ESP board for interfacing is not an option. The solution in situations like this is to use opto-isolation, so that interfaced devices can be electrically isolated from one another.

Rather than use off-the-shelf options, [Zak] opted to keep things small and economical by rolling his own solution using side-mounted IR LEDs on the small interface PCB. LEDs can also act as photodiodes, so by pointing two LEDs directly at one another and driving one LED from the door control system and measuring the small amount of resulting current on the other LED, [Zak] can detect states without having to directly connect a GPIO pin.

One such opto-isolator works to detect the door buzz, and another works to cleverly sense and control the different states of the lock. A bit of additional work is needed to deal with the idiosyncrasies of the AC door system, but the result seems to work very well.

A Node.js application works with the board to provide integration with Telegram, which allows for groups to receive event notifications, and frees the system from being location-bound to the apartment.

As for improvements, there’s even an auto-unlock feature to automatically unlock the door if the buzzer is pressed within 5 minutes, which [Zak] finds very handy for the times he’s carrying up a load of groceries and doesn’t want to fumble around with keys.

We’ve previously seen [Zak] give things the IoT treatment, and the results are always impressive. Check out his battery-sipping mailbox notifier for a great example of making everyday tasks more efficient.

It has become a bit of a running joke in the Hackaday community to suggest that a project could or should have been done with a 555 timer. [Tim] has rather taken this to heart with his latest Electronic Dice project, which uses three of the venerable devices.

If three seems like a lot of 555s to make an electronic die, then it may be worth considering that the last time we shared his project he was using 22 of them! Since then, [Tim] has been busy optimising his design, whilst keeping within the constraints of an old-school through-hole soldering kit.

Maybe the most surprising thing about this project is the purpose to which the NE555 devices are pressed. Rather than using them for their famous oscillation properties, they are in actual fact just being used as Schmitt Triggers to clean up the three-phase ring oscillator that is constructed from discrete transistors and passives.

The ring oscillator cleverly produces three phase-shifted square waves such that a binary combination of the three phases offers six unique states. Six being the perfect number for a dice throw, all that then remains is to figure out which LEDs need to be switched on in which state and wire them up accordingly.

To “roll” the dice, a push-button powers up the oscillator, and stops it again when it is released, displaying the random end-state on the LEDs.

It can be fun to see what can be done using old technology, and educational to try to optimise a design down to the fewest parts possible.

[Tim]’s earlier project is here if you want to see how the design has evolved. The documentation on both of these iterations is excellent and well worth a read.

With modern microcontrollers, the process of interfacing with the analogue world is easy. Simply enable the on-board DAC or ADC, and talk to the world. If you’ve ever done this with a slightly older microprocessor, you might have encountered the DAC and ADC as chips in their own right, but how about the earliest generation of microprocessors? In those days, if an analogue component was needed, the circuit which would later be integrated on chip would have to be made from scratch. So it is that [Florian Wilhelm Dirnberger] has built a very old-style 6-bit DAC, using a circuit that would have been familiar back in the early 1970s.

At its heart are a pair of 4007 triple CMOS inverters, which form the six bits driving a resistor ladder DAC. This is simply a chair of R… 2R resistors, relying on Ohm’s law for its operation. Each successive bit contributes twice the current to the output of its predecessor, and the 4007 simply provides a buffered supply for the bits.

It’s the simplest of DACs, if not the most capable. Back in the day a typical ADC might also use this circuit, feeding a comparator alongside the input voltage. The microprocessor would count through the digital values until the comparator output bit flipped, at which point it would take the counter value as the analogue measure. You may never need to build one when your microcontroller has one built in, but it’s useful to know how simple DACs and ADCs work.

If the subject interests you, we’ve had a look at DACs including resistor ladders used in audio.

[Kyle Owen], collector of antique tech, decided to try his hand at music arrangement — for the PDP-8 computer, that is (listen to the video below the break). He’s using a program submitted by Richard Wilson to the Digital Equipment Corporation Users Society (DECUS) in 1976, appropriately named MUSIC. It runs on OS/8 and is written in the PDP-8 assembly language PAL8. Using the syntax of MUSIC, [Kyle] arranged Gershon Kingsley’s famous Moog synthesizer hit “Popcorn” (the Hot Butter version from 1972).

You might notice the lack of a disk or tape drive in his setup. That’s because [Kyle] is using an RK05 disk emulator he wrote back in 2014. It’s running on a Raspberry Pi and connects over serial, which he says is slower than an RK05 but faster than a tape drive. He has connected up a Cordovox amplifier cabinet for this demonstration, but the original means of listening to the MUSIC output was an AM radio held near the computer (hear the second video below the break). This worked by executing the PDP-8 CAF instruction at a desired frequency, say 440 Hz.

Thus, when this instruction is executed, logic all over the computer goes “zap”, clearing out various registers. Now, if a radio is held close to the computer, it will pick up some of this energy, and at 440 times a second, will deliver a pulse to the speaker. The result is that you will hear a tone from the radio — as a matter of fact, you will hear an A.

You can read more about this program and how it operates in the original program description in the original DECUS submission.

[Glen Akins] had a WW2-era aircraft engine cowl flap indicator lying around (as you do) and thought it would make a jolly fine USB-attached indicator. The model in question is a General Electric model 8DJ4PBV DC Selsyn, which was intended for four-engined aircraft. For those not familiar with the purpose [Glen] explains in his detailed writeup, that piston-engine aircraft of that era were air-cooled, and during conditions of maximum engine power — such as during take-off — flaps on the side of the engine cowling could be opened to admit additional cooling airflow. These indicator dials were connected to a sender unit on each of the flap actuators, providing the pilots an indication of the flaps’ positions.

The mode of operation in the DC power environment of WW2-era aircraft utilised the concept of variable magnetic field orientation. The sender is a potentiometer, sending a voltage down the wire between 24V and ground. The indicator unit has a pair of coils set at 120 degrees around a ring, with the coils wired in series, and the center tap connected to the sender signal. The other ends of each coil connect to the DC power bus so that as the signal voltage varies, the coils produce a varying magnetic field. Lower voltages bias the field towards the coil connected to 24V, and higher voltages the other way. A permanent magnet in the center is attached to the indicator dial, with a small spring to bias it to the center. A very simple but effective arrangement, giving analog feedback of the actual flap position.

To interface this thing to modern technology, a custom PCB was constructed leveraging the USB functionality of the PIC16F1459 microcontroller, that [Glen] was already familiar with. Four Microchip MCP31HV41-502 digital potentiometers were pressed into service directly driving the coils of the indicator units. That might seem like an odd if not viable way to drive such a thing, but [Glen] goes into some extensive theory and some modeling to determine which devices would have sufficient margin, which is worth a read for the unfamiliar. After bit-banging the SPI connection to the digipots (even though the PIC has hardware SPI) [Glen] goes on to describe how the USB endpoints work, finishing off with a .NET application to drive it all.

We’ve seen plenty of hacks bringing retro hardware back to life, connecting to modern computing. Here’s a project that goes the other way, building custom aircraft instrumentation from modern parts.

What’s a Scramblepad? It’s a type of number pad in which the numbers aren’t in fixed locations, and can only be seen from a narrow viewing angle. Every time the pad is activated, the buttons have different numbers. That way, a constant numerical code isn’t telegraphed by either button wear, or finger positions when punching it in. [Glen Akins] got his hands on one last year and figured out how to interface to it, and shared loads of nice photos and details about just how complicated this device was on the inside.

Patented in 1982 and used for access control, a Scramblepad aimed to avoid the risk of someone inferring a code by watching a user punch it in, while also preventing information leakage via wear and tear on the keys themselves. They were designed to solve some specific issues, but as [Glen] points out, there are many good reasons they aren’t used today. Not only is their accessibility poor (they only worked at a certain height and viewing angle, and aren’t accessible to sight-impaired folks) but on top of that they are complex, expensive, and not vandal-proof.

[Glen]’s Scramblepad might be obsolete, but with its black build, sharp lines, and red LED 7-segment displays it has an undeniable style. It also includes an RFID reader, allowing it to act as a kind of two-factor access control.

On the inside, the reader is a hefty piece of hardware with multiple layers of PCBs and antennas. Despite all the electronics crammed into the Scramblepad, all by itself it doesn’t do much. A central controller is what actually controls door access, and the pad communicates to this board via an unencrypted, proprietary protocol. [Glen] went through the work of decoding this, and designed a simplified board that he plans to use for his own door access controller.

In the meantime, it’s a great peek inside a neat piece of hardware. You can see [Glen]’s Scramblepad in action in the short video embedded below.

If you’ve used a corporate VPN or an online-banking system in the past fifteen years or so, chances are you’ve got a few of those little authenticator key fobs lying around, still displaying a new code every 30 seconds. Today such one-time codes are typically sent to you by text message or generated by a dedicated smartphone app, which is convenient but a bit boring. If you miss having a dedicated piece of hardware for your login codes, then we’ve got good news for you: [Cameron Kaiser] has managed to turn a Commodore SX-64 into a two-factor authenticator. Unlike a key fob that’s one gadget you’re not likely to lose, and any thief would probably need to spend quite some time figuring out how to operate it.

The SX-64, if you’re not familiar, is the portable version of the venerable Commodore 64. Weighing in at more than 10 kg it’s not quite a MacBook Air, but it does come with a built-in color monitor and 5.25″ floppy drive. The CPU is an 8-bit 6510 running at about 1 MHz, and as you might imagine it was not a trivial task to implement cryptographic routines on it. Working directly from the definitions in RFC 6238, [Cameron] first determined all the necessary bits: an SHA-1 hasher, an HMAC generator and several routines to manipulate dates and times.

The SHA-1 algorithm and HMAC functions might seem complex, but in the end they boil down to performing addition, subtraction and several bitwise logical functions on 32-bit numbers. Lots of steps if you can only work with eight bits at a time, but nothing that even a 6510 can’t do in a reasonable amount of time, especially when running carefully hand-crafted assembly code.

Working with dates and times turned out to be more complicated. The few real-time clock add-ons that were available for the Commodore 64 series all return the time directly in human-readable format: great for everyday use but not so great for calculations that require Unix time. Converting between the two involves lots of multiplication and division, which takes forever if you don’t have a hardware multiplier. [Cameron]’s blog post is full of detail on how to optimize calculations on constrained hardware, and is an interesting read even if you’re working with modern processors.

The end result of the exercise looks almost exactly like a typical authentication app on your smartphone, including that annoying countdown bar. If you’re looking for a slightly more compact solution, you can do the same thing on an ESP32. Need a refresher on two-factor authentication techniques? We’ve got you covered.

Designed with a minuscule footprint, this fully-functional CP/M computer build uses just two main components: a Tiny 2040 and an Adafruit microSD reader.

Software engineer and vintage computing enthusiast Kian Ryan writes:

“I’ve been using the RC2014 as a a CP/M development machine, especially while developing a cross-platform Rogue-like game. I love it,” Ryan explains, referring to the popular modular Zilog Z80 computer kit. “And whilst it’s a hell of a lot more portable than carrying a Osborne 1 or a Amstrad CPC 6128, it’s not something I can keep in the laptop bag and just pull out at the coffee shop (Both the RC2014 Mini with CP/M upgrade and the Extreme Kits RC2040 are ideally suited for this). I wanted to see if I could put together a truly tiny CP/M based system using RunCPM and the RunCPM-Pi-Pico project and make it even smaller.”

You can see more on hackster.io and on this blog and GitHub.

It used to be that every well-stocked doomsday bunker had a Geiger counter. These days, you don’t have to have a big tube-based meter. You can inexpensively get a compact digital instrument to handle your radiation detection needs. [DiodeGoneWild] reviews and tears down such a unit from FNIRSI. The case looks like several other similar instruments we’ve seen lately, so presumably, someone is mass-producing these handheld meter cases. You can see the video, below. The meter reads the absolute radioactivity and can also measure cumulative exposure.

After measuring a few common radioactive items, we get to the teardown. Inside, of course, is an ordinary tube. A few screws reveal a typical rechargeable battery, a fairly simple PCB with a microcontroller and battery backup for the real-time clock. A lot of the board is involved in multiplying voltage up to the several hundred volts required for the Geiger tube.

The other side of the PCB has only buttons, a vibration motor, and, of course, the LCD. We don’t know how you might test the relative accuracy other than comparing it to a known-good meter. The bare tube was, of course, more sensitive without the plastic cover, but that could be calibrated out, too.

A Geiger counter doesn’t have to have a lot of parts. Either way, a surprising number of things will set them off.