Acidbourbon has published a new build, a wireless touchpad that can be used like an expression pedal:
This sort of touchpad speaks some special Apple mouse protocol. Luckily I found a code snippet on mikrocontroller.net which helped a great deal to get the thing going.
Then I used a standard AVR ATMega8 microcontroller to glue the transmitter and the touchpad together. That means, I poll the status/position change from the touchpad and if some swiping action was detected, the relative change of coordinates is sent via the radio.
I designed a compact double sided PCB housing both the microcontroller and the radio. It also features a 5V voltage regulator for the microcontroller and the power supply of the touchpad, as well as a 3.3V regulator for supplying the radio.
The touchpad is then connected to one of the free GPIO pins of the microcontroller which are accessible via dedicated pin headers
Project info at Acidbourbon homepage.
Check out the video after the break.