Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:3168775.
Made this a while ago for a small project that uses a Teensy 2.0 board and an <a href="https://www.amazon.com/gp/product/B00063678K/ref=as_li_qf_asin_il_tl?ie=UTF8&tag=poptartingcom-20&creative=9325&linkCode=as2&creativeASIN=B00063678K&linkId=16dccbbc5254008a26dab6b36e9b091b">M-Audio foot pedal (Amazon)</a>, so I can use it for push-to-talk in games or on Discord. The foot pedal just uses a standard 1/4" jack and acts as a digital switch on the Teensy board which then sends a joystick button press when it's held down. These are the 1/4" jacks I used: https://www.amazon.com/gp/product/B00063678K/ref=as_li_qf_asin_il_tl?ie=UTF8&tag=poptartingcom-20&creative=9325&linkCode=as2&creativeASIN=B00063678K&linkId=16dccbbc5254008a26dab6b36e9b091b The Teensy 2.0 has 25 digital inputs so you could easily make a larger box with more inputs.
I found that a lot of the cheap USB foot pedals on Amazon wouldn't work the way I wanted. The one I bought would only do a single key press when held down.