Craving this simplicity, [Tom] invented the Cheap Universal LED Driver, or CULD, to do the job instead. The CULD is designed as a simple LED indicator that will light up anywhere from 5V to 50V.

If an LED isn’t dim enough for you after one sticker, you can stack a second one on top of it. LightDims Black Out Edition, which are designed to block 100 percent of an LED’s light.