Software for Matti

By Ward Dehairs, April 1, 2020

Working at Creative Therapy I have been mostly concerned with the development of Matti, in particular games, analysis tools and firmware.


First prototype Matti, built by Creative Therapy.

Matti is a device containing a large array of LEDs and pressure sensors, which acts as an input and output for games and other applications. The goal of Matti is to be a tool for physiotherapists, engaged in rehabilitation, sports measuring and care for children or the elderly. The device connects to a PC which runs MattiUnity; the application containing the games and analysis tools that work with the Matti.


MattiUnity application, showing the pressure heatmap of a person standing on the Matti.

Working at creative therapy, my first and main job was to build up the application (Matti-Unity) from scratch, providing code to communicate with the Matti via USB port, processing the input, facilitating games and sending LED output back. While this is not too difficult in principle, the reality is quite complex. Some of the challenges I faced include:

  • Creating a simple system for rendering images to the Matti
  • Creating a mapping between LEDs and sensors, noting that the sensors at 56 x 56 are much more numerous than the LEDs at 18 x 18, the squares do not line up and can even vary from Matti to Matti
  • Writing automated code for filtering sensor values and dealing with dead lines
  • Writing code to linearize the output of the sensors
  • Writing firmware for handling Matti IO on Teensy Arduino
  • Writing firmware for handling Matti IO on Raspberry pi
  • Designing a system for connecting the Matti via wifi
  • Designing a system for connecting the Matti to a browser application
Matti innards

Inside of a Matti, showing the pressure sensor array (on top) and the led strips glued onto a foam base.

Net surfer

One of the more fancy games made for Matti-Unity, specifically an intern project made by game development students.

Balance orchestra

Icon for the balance orchestra game, where the player must balance between left/right to guide an orchestra playing a symphony. Made by Jorn Ockermans for Creative Therapy.