Programming with NEPO® follows a simple principle. The blocks are interconnected and executed by the robot according to their order. This principle is called »sequential operation«. Only blocks that are connected with each other are executed while running the program. The blocks that are connected together and to the start block are also called a sequence or »task«.
To connect blocks with each other, they have sequence connections and/or connectors. Depending on the mode of a block, the number of the connectors may vary.
Programming with NEPO is really easy. Every program begins with the »start« block.
This block is always added by default in the Open Roberta Lab workspace. The first block that you will execute is connected with the »sequence connector« of the »start« block. The sequence connector is a triangle at the bottom of the block and this triangle will become yellow as soon as a suitable block is in close proximity.
Your first program - Hello Roberta
Let's write our first program for the EV3. We will use the block " Say ..." from the action category. In the associated text block you can now write a text that your EV3 should say.
This is a very simple program and should only show you the basic possibilities of the Open Roberta Lab and your robot.
Configuration
Before you can then program your robot, you must first configure the sensors and actuators. You can find the different sensors and actuators available for the mBot here.
For each sensor and actuator, you will find a description of its function and how to connect it.
Transfer a program to the mBot
So that you can try out your first program, it must of course first transfer it to your mBot. Just press the »Start on mBot« button as long as there is a connection between the Open Roberta Lab and your mBot. You can read how to connect your mBot to the lab here.
NEPO
NEPO is the name of our graphical programming language. It is easy and fun to learn programming. NEPO can also be used to program and interact with other robot systems.
Perhaps NEPO seems familiar to you. When designing NEPO we were inspired by existing concepts from scratch and blockly.
The graphical NEPO blocks have different components and thus different attributes. A block always represents a certain functionality. Its function can easily be determined by its block category, for example »sensors« . Features of the graphical blocks are:
Selection Menu
In the selection menu you can choose between different functions for the block, such as in block »play ... note« between whole, half, quarter, eighth and sixteenth.
Sequence connection
The blocks are connected to each other using the sequence connection. A program consists of all the linked blocks. The blocks are executed according to their order, from top to bottom. A NEPO block can have at least one sequence connector and a maximum of two, usually two.
Parameter
Input - Parameter Input
Depending on the block different values can be passed to a block. The type of the value can be identified by the colored compounds (called »connectors« ) of a block. In the chapter »block catagory« you can see the different values a block can have. Blocks can only be connected when the colors of the input and the output connector match,.
Output - Return parameters
A block may optionally also pass a value (only one) to another block. These blocks have colored output connectors. Blocks can only be connected when the colors of the input and the output connector match.
Contextmenu
By rightclicking a block its contextmenu can be opened.
Several actions can be performed, using the menu:
- Duplicate (copys the block and connected input parameters)
- Add comment (adds a comment to this block)
- Inline Inputs (changes the appearance of the block)
- Collapse Block (minimizes the block)
- Disable Block (deactivates the block so that it won't be executed)
- Delete x Blocks (deletes the selected and all connected blocks)
Datatypes
There are seven different input and output types within NEPO. These types are as follows:
Remember, not all data types are supported by all robots/systems!
- Logical value (light blue)
- Number (dark blue)
- String/Text (green)
- Color (yellow)
- List (purple)
- Connection (pink)
- Image (magenta
NEPO offers eleven block categories:
| Action | x | x |
Sensor | x | x |
| Control | x | x |
| Logic | x | x |
| Math | x | x |
| Text | x | x |
| Lists | x | |
| Colours | x | x |
| Variables | x | x |
| Functions | x | |
| Messages | x |
Programming Languages for Code Generation
| WeDo | Stackmachine JSON Code (It runs in the browser, editing is not recommended) |
EV3lejos 0.9.0, 0.9.1 Open Roberta xNN | Java |
EV3Dev NAO mBot 2 | Python |
EV3 c4ev3 Calliope mini ... | C/C++ |
| NXT | C (NXC, not exactly C) |
| micro:bit | MicroPython |
| Spike Prime/Robot Inventor | MicroPython |
| Edison | MicroPython (very limited) |
ROB3RTA BOB3 SenseBox mBot NEPO4Arduino Bionics Kit Bionic Flower Bot'n Roll | Arduino C/C++ |
Arduino C/C++ is actually C/C++, but a somewhat reduced selection from C/C++.
MicroPython is Python for microcontrollers.
Blockdescriptions
The individual blocks and their descriptions can be found here, sorted by categories.
For each block its function, setting possibilities, as well as input and output values are described in detail.
Sample programs
In the section »Example programs mBot« we show you different example programs. For each program there is a short description and a "sample solution". Each example program is divided as follows:
- Description
- Table
- sensors
- actuators
- block category
- difficulty
- tips
- Result
So far we have put the following sample programs online:
- The LEDs switch on
- Flashing lights
- Measuring the distance
- parking sensor
- Line follower