- Expansion for Fischertechnik Robo TX - 


 FischertechnikExpRoboPro320x240 FischertechnikExpBot320x240 


 The TWI routines in the firmware are written by Martin Junghans. Details can be found in the source code.

The Project

The RoboTX controller made by Fischertechnik, together with its software RoboPro, is a nice development system for children to learn how to program using a simple GUI.
The number of IO-ports on the RoboTX controller is very limited. So I developed an expansions circuit that adds another 8 digital inputs and 8 PWM controlled outputs. Two output can be used together to drive a PWM controlled motor in both directions.
The expansion is interfaced to the Robo TX controller using the I²C (also called TWI by Atmel) interface. I²C support requires the newest version of firmware and software for the Robo TX controller!
Please note that I built my expansion using a piece of prototyping PCB. I have never built it using the PCB included in this project.

Technical Data

  • 8 digital inputs
  • 8 PWM controlled outputs, up to 200mA. Pairs of outputs can be used to drive a motor in both directions.
  • I²C interface to the RoboTX controller (use the right side connector). Base address used is 0x20 (HEX).

Included in the project files

All files to build the board are included in the project files.

Further Information

Circuit and PCB description


We use cookies on our website. Some of them are essential for the operation of the site, while others help us to improve this site and the user experience (tracking cookies). You can decide for yourself whether you want to allow cookies or not. Please note that if you reject them, you may not be able to use all the functionalities of the site.