/diy/ - Do It Yourself

>>1851415
Dude that's a very broad question but here are a couple random ideas:
>Curve tracer. The concept is easy to learn but will make you think, plus you get a fun instrument to check out that can be very useful. Linearity of devices is crucial.
>An audio level meter using magic eye tubes. Did this the other day and it looks cool plus it's easy. If you don't like tubes then LM3915 in bar mode. Easy. Cheap. Kills time and who doesn't like flashing blinkenlighten?
>Signal tracer.
>50W/chan. audio amp with LM3876. Cheap and phenomenal performance for what you pay but the power supply may be the most expensive part.
>Dual tracking power supply with LM317/337; bootstrap for extra current and add current limiting for a hair pulling good time.
>Buy and fix an old radio, I'm doing a Zenith TO and it is a lot of fun but be prepared to hunt for tubes or parts. Avoid germanium stuff unless you are comfortable cross referencing components as NTE is a ripoff and the Russians make better germanium devices.
>Find a POS toy like a tickle me elmo and circuit bend the hell out of it...or...embed light sensors in the eyes and replace the circuit with something more interesting like a delayed whispered voice after it detects someone in the room or it screams on sight. Be warned: your unfortunate victim will probably destroy it or will br very mad with you.
>A delayed chirp box...make a circuit that chirps like a bird every 45 mins or so and hide that box. This thing drives people batshit and is fun to watch. April fools becomes a little more entertaning...
Hope that gives you some inspiration.