Seeing as my past week has been… taxing… and I had a lot of free time on my hands, and an obsolete piano to make useful, I made a foot pedal for the thing using as little money as possible (shocking)!
I didn’t feel like plopping $15 on a low-end foot/sustain pedal for a piano that I might or might not care about after the summer. So I took it upon myself to craft one using basic childhood skills of cobble-and-test (a step or two down from legit engineering). I had originally intended to make it an actual pedal, complete with a hinge/pivot and moving parts. Then, I realized that making something functional and decent was overrated. All I needed was, essentially, an on and off switch controlled by a foot. So I made a cantilever, a thin (1/4″) wood beam with a contact underneath that completed a circuit when it touched the base. I tested the wood in a clamp to make sure it could bend far enough work (about half an inch per 7 inch length).
The electrical component of the project was pretty straight-forward. The piano keyboard (old old Casio CT640) used a quarter inch TRS (audio jack) input for the pedal. I used an adapter to change the plug size to 3.5 mm (your typical headphone plug size) and soldered some old speaker wires to them, one to the tip, one to the sleeve. The ends of the wires ran to contacts, in this case a nickel and some aluminum foil.
Shockingly enough, it works. Total expenditures: ~$5, with extra wood left over.
Considerations for future builds: Use a deeper base (in the back, 2-2.5 inches) and a shorter beam/pedal (~6 inches), and reduce the distance between contacts. The way it’s set up now puts a lot of stress on the connection between the floor plate and the pedal part. It’s held together by a few screws, and you can see some cracking from where I tightened it too much underneath.