Simple USB Foot Pedal - Single Switch

The version I made uses a Seeed Studio XIAO RP2040 microcontroller wired to a cherry mx profile switch. any microcontroller that has an RP2040 chip will work too. it uses very basic KMK firmware to emulate a keyboard, and the key can be changed to whatever you want in the code (default is P). 

Assembly uses 4 m4 bolts (22mm) and 4 m4 nuts. You can use hot glue or any other kind of glue if you want, but it will make it harder to take apart in the future. the plug for the cable is fairly secure without glue but i use some hot glue around it for extra support. I also put some painters tape over the controller and the cable so the switch doesn't come in contact with any metal parts and trigger a key input. any tape or material will be fine, I just used painters tape so it doesn't leave any residue. Lastly if you want you can add some weights or rubber feet on it to help it not move around as much

The blank cable plug is so you can make your own depending on how large your cable is. the one i used in the pictures is the usb-c to usb-a cable that comes with the switch pro controller.

Firmware

i used this video to learn how to install KMK: 

and the code for the pedal is included in the files. note that the circuit python flash file is different for the pi pico and the xiao. you can find the uf2 here. its almost identical from the example code on the get hub page, but changed to use pins D2 and D3 and output “p”

KMK firmware: https://github.com/KMKfw/kmk_firmware

KMK Documentation: http://kmkfw.io/docs/

happy printing and if I need to change anything, let me know.