Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:4641514.
Remix of the original foot pedal by Gripuf for the Xbox adaptive controller. This version hollows out the base and uses a micro Arduino Leonardo to act as the go-between. This is also effectively a re-mix code from David Madison who created the Arduino macro keyboard.
The button needs to be soldered to pin 9 of the Arduino and the other pin of the button to one of the ground pins.
I also used a small USB panel mount cable to connect the Arduino to the outside of the pedal and M3 bolts to screw the base to the body. (https://smile.amazon.co.uk/gp/product/B07DS6KBJX/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1 )
The pedal will appear as a HID Keyboard to Windows/Linux/MacOS and the code attached is set up to press the space bar. Although it can be anything really, including a macro. There is the possibility of adding more pedals by exposing the remaining pins on the Arduino as external connectors and using simplified mono 3.5m headphone jacks to connect them. Making the pedal with the Arduino act as the aggregator for the other pedals so they wouldn't need further electronics.
I created this for my sister-in-law after they rang me to ask about modifying a piano foot pedal to act as a space bar as she is having increasing problems pressing the spacebar due to early onset arthritis.