TLC555 Low-Power LED Beacon

The CMOS cousin of the 555 runs the same astable circuit on a tenth of the current — perfect for battery-powered blinkers.

Difficulty: Breadboard. Estimated build time: about 30 minutes. Estimated parts cost: about US$2.50. 7-part bill of materials with live supplier pricing. A blinking LED beacon built around the TLC555, the CMOS reincarnation of the bipolar NE555.