phi-T Control is a foot controller, that sends out MIDI Control Change Messages via USB. The project is based on V-USB-MIDI, adapted to my requirements.
I’m using an AVR ATmega8 with 5 potentiometers, foot switches and LEDs. One of these is used for a foot pedal. Unlike in the V-USB-MIDI project, I’m doing the level conversion with zener diodes, as it is explained here. Furthermore, I had to rewrite the source code at different places. The case is made of 1 mm stainless steel. I’ve created the DXF files with Pro/Engineer, and have had them laser cut by my father’s company.
The whole circuit is built on a stripboard. All in all, there aren’t many electronic components necessary:
- 5 x 10 k linear potentiometers
- 5 x foot switches
- 5 x LEDs
- 12 MHz crystal resonator
- Reset: 10 k to Vcc and 100 n to GND
- USB jack with zener diodes
- Bulk capacitors (4μ7 and 100 n) between Vcc and GND
I’ve built the project in AVR-Studio 5. The project files, a ready to burn HEX file and the DXF files for the case can be downloaded here:
AVR is a registered trademark of Atmel Corporation
Pro/Engineer is a registered trademark of Parametric Technology Corporation