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Web application and Micro:bit program to wirelessly control a Micro:bit robot platform.

R4G System overview

About the project

The ZIMD (Center for Interaction, Media & Social Diversity) offers a workshop format, where girls build and program robots from Lego bricks. The workshops are offered for girls in fifth grade. The aim of the workshops is to inspire the 10- to 11-year old girls in technology and especially robotics. Building on the LEGO Mindstorms Robotics Invention System (RIS)(1998), the Fraunhofer Institute for Intelligent Analysis and Information Systems (IAIS) has developed the didactic concept for this girl project, and the ZIMD has further expanded and refined it since 2006. At the heart of the RIS is the Robotic Command eXplorer (RCX) unit, a compact yellow block incorporating an 8-bit microcontroller. The RCX controls the LEGO RIS hardware and can be programmed with the proprietary RIS software. Since the release of RIS in 1998, two new Lego Mindstorms systems were released and support for the RCX unit has been discontinued. The remaining RCX units are operated with the help of outdated technology and are cumbersome to handle from today's perspective. In order to update the proven ZIMD workshops, the project Robo4girls was launched by ZIMD in October 2018 and funded by netidee. The technical goal of this project was to develop the R4G block, a control unit that replaces the RCX in the ZIMD workshops. The developed R4G block is based on a BBC Micro:bit and can be programmed via a mobile device with the R4G web application.

This repository hosts the R4G web application, which can be reached at It also contains instructions on how to build the R4G block and how to control it with the R4G web app. If you are using a Micro:bit V2 with an onboard speaker, I recommend you use the instead.


Testing the setup

You can test our R4G App with a computer, a Micro:bit and an USB cable.

List of materials

  • a Micro:bit with usb cable
  • a computer with internet access
  • optionally a piezo buzzer
  • optionally 2 croco clamps to connect the buzzer to your Micro:bit. If you do not have croco clamps just use scotch tape and tape the ends of the buzzer cables to the pins of your Micro:bit.

Prepare the Micro:bit

Connect your Micro:bit to your computer via USB and load one of the R4G_MICROBIT.hex files on to your Micro:bit. The R4G_MICROBIT.hex files are in the microbit folder of this repository. If you have connected motors via a Micro:bit motor driver board from Keyestudio, from Elecfreaks or from Waveshare, choose the respective hex file (ks, ef or ws). Otherwise choose either one. If you do not know how to upload a program to your Micro:bit you can look it up here. If you have a buzzer: Connect Pin 0 and GND-Pin of your micro:bit to the piezo buzzer like shown in this fritzing wiring diagram

Connect and program the Micro:bit with the R4G web app

Open the google chrome browser on your mobile device and navigate to the R4G web application. Don't forget to activate Bluetooth on your device! On the R4G website click the Verbinden button, choose your micro:bit from the list and click Koppeln. Wait a few seconds until a confirmation message pops up. If the connection is not established quickly, disconnect the Micro:bit from its power source (computer or battery) and wait for one minute, then try again. If you still cannot establish a connection restart your mobile device. If the Micro:bit is successfully connected, it scrolls a "C" over its LED display.

Now you can program the R4G robot by selecting blocks from the Blockly toolbox and dragging them into the workspace. If you click on one of the 6 sections in the toolbox it will list all blocks available in this section.

blockly toolbox

You can drag & drop the blocks you want in the workspace. To create a program connect the individual blocks to a chain. To connect the blocks drag a block close to another block until the background between them turns gray and then release it. The blocks snap in place and you should hear a clicking sound when they connect. To start the program click Start. Melodies and Movements will only work if you have a buzzer and motors connected to your Micro:bit.

Have Fun!


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