An original xbox controller has 8 channels of low-res analog, 4 channels of hi-res analog, and 8 channels of digital inputs.
I tied the low-res channels to my front row of pedals. Soldered a wire to a bit of pcb, ran the wire through the resistive foam, and through the base plate. The base plate acts as the ground plane, and the wire holds the foam in place.
Original xbox controller inputs expect ~0-4.7k on each channel. The resistive foam measured from ~0-1k. Added a 1k pull up resistor to each channel to re-center the input range.
The pedals are solid aluminum from a bit of bar scrap I had. Home annodized with an old UPS transformer/battery acid, dipped in Ritt dye, steam cured.
The force required is adjustable via the screws through the pedal face. They terminate in a nut through some latex tubing which acts as an effective return spring.
Rear row are micro switches from an old vcr faceplate and connect to the digital inputs.
The 4 hi-res inputs I terminated in phono jacks on the back panel for use with standard wah-wah pedals.