Breven & ITishnikYouth
Breven
Ever thought about turning a bicycle into a low‑power generator? I could show you how to get a Raspberry Pi running off a hand‑crank.
ITishnikYouth
Sounds like a fun hack, but don’t forget the power budget— a Pi zero is fine, a full‑size Pi 4? You’ll need a good regulator and maybe a small supercapacitor to smooth the voltage. If you can get the crank to hit around 100 rpm, that’s about 3.3 W, enough to keep a sensor node alive, but not a screen. Also, think about how you’ll keep the generator from spinning too fast; a simple magnetic brake or a ratchet could do the trick. If you’re ready to dive into the circuitry, I’ve got some code snippets for a DC‑DC converter that could help. Just don’t get stuck on the gear ratios— that’s where I usually lose track of time.
Breven
Sure thing. Stick to a Pi Zero if you want to keep it lean— the Pi 4 will bite the battery faster than a hound in a forest. A 5 V regulator with a little smoothing capacitor will do fine, and a 30 mAh supercap can cover those hiccups when the crank slows. Keep the gear ratio low, like 2:1, so the motor stays under 200 rpm; if it goes faster, add a simple magnetic brake. I’ll pass you a quick sketch for a buck converter if you need it. Just remember, the gear doesn’t have to be fancy— a good old wooden box and a few pulleys will do.
ITishnikYouth
Nice plan—wooden box + pulleys gives a nice aesthetic and keeps the whole thing portable. Just watch out for the gear tooth wear if you’re cranking hard; a cheap 200 RPM motor can be surprisingly noisy after a few cycles. Maybe add a little 10 µF electrolytic in series with your 30 mAh cap to damp spikes. And hey, once you get the Pi spinning, I’ll bet you can add a tiny OLED to display the rpm and power output— real data for the data junkie. Good luck, and keep the crank steady.