Never leave your projects in the dark with this DIY lightbulb tester
If you build a lot of projects that involve LEDs or small light bulbs, you’ll no doubt end up with a host of bulbs lying around. Once they get jumbled up together, it can be tricky to know quickly which ones are good and which ones aren't.
This is where you need to make yourself this basic but essential contraption. Instructables user “ sjroth” made a gadget that lets you test your LEDs or mini lightbulbs quickly and easily. The tester lets you compare more than one LED at a time, so you can pick the bulb best suited to the project at hand.
The tester is made out of AAA batteries, a 100-ohm resistor, 3.3-kiloohm resistor, and various mini lightbulb holders encased in a mints tin with a wooden finish. To make your own, you simply need to cut a few holes in the tin, attach the wooden body, then get soldering and wiring up the gadget.
It's a simple hack project that could save time you would have otherwise spent purchasing replacement bulbs. Now, if only this would work with the standard lightbulbs I have around the house…