I do a lot of hardware hacking, both as a hobby and as a profession. I use a lot of electronic supplies, but I use these often enough that they’ve become staples in the workshop. Perhaps you’ll get some inspiration?
5) Phenolic Veroboard. Like perfboard, I use this to rapidly bash together permanent one-off circuits. Unlike perfboard, Veroboard has long connected copper strips instead of those little isolated islands. This means long bussed connections are already made, saving you lots of time. Get the phenolic, not the fiberglass – you can cut it with a utility knife and it doesn’t throw off toxic fiberglass dust. I buy my Veroboard from Amazon – this particular pack is unbelievably cheap. Legend has it that there’s a special Veroboard trace-cutting tool, but I’ll be damned if I can get one!
4) Arduino Trail Mix. I use Arduino, like, a lot, but if I bought an actual Arduino every time, I’d be broke and the projects would be massive. I pre-load an ATMega328P chip with the Arduino bootloader and toss it in a static bag with a 16MHz resonator, five 0.1uF ceramic caps, and an LM7805 regulator. That’s effectively an Arduino Uno, and it’s about $4. I call it Arduino Trail Mix.
3) IRF510 N-Channel Enhancement MOSFET. This is a fast and big-ass transistor that switches a lot of current and voltage. Need to control a 24V motor? Grab four and make an H-bridge. Need to PWM three amps of LED strip? Bolt on a piece of scrap aluminum and go buck-wild. Have three minutes to make a touch-sensitive switch? Toss on a weak pull-up and save the day. The best 50¢ you can put in your parts stash. The only downside is that they switch around 3.5V, so your Raspberry Pi and stuff needs a BJT to drive it. Small sacrifices.
2) Encapsulated Reed Switch. A reed switch is an electromechanical magnetic switch – it physically closes the circuit when a magnet comes near. It’s not sexy, but it’s the best non-contact switch you can find. Great for detecting open doors, making dirt-cheap object identification by gluing on arrays of magnets, and embedding hidden switches activated by tricky magnetic rings. Pay the extra quarter for the encapsulated switches – non-encapsulated means exposed glass, and glass breaks.
1) Hot Glue. This is the Frank’s Red Hot of hardware hacking – I put this s**t on everything. My projects look so clean because the inside is effectively one giant glob of hot glue precisely suspending everything in place. Hot glue is truly the prototyper’s best friend – it’s easy to apply and mold, sticks to damn near everything, cleans up easily, and is easy to tear off and redo. My only complaint is that it doesn’t do a great job sticking to 3D-printed PLA, but that’s fine, because I can just make the whole damn print out of hot glue instead!