I just whipped up this LED tester tonight while at the lab. The two probes provide just the right power for a single normal LED. I built it because I need a way to test tiny surface mount LEDs.
I plan on leaving it at the lab for everyone to use. Keep in mind though this is the alpha model, and while functional, it could do with some design improvements. I intend for the beta to include; an on/off switch, a built in power indicator LED, a variable resistor (so one can measure multiple LEDs at once) and some sort of case or cover for stowage of the pins so they won’t get bent.