“It’s the dark season again, and time to plaster our child’s clothing with reflectors and lights in an effort to increase safety. Hats with front lamps are a thing, and headlamps exist also, but neither seems to work that well for making a kid visible from any direction. So it was time to make my own.
I chose to run the LEDs on a single AAA battery to keep the weight down. To step up the voltage I’m using MCP1640 synchronous boost chip. Because MCP1640 fully disconnects the output when off, it is possible to use it also as the main power switch. When in standby, MCP1640 itself takes less than 1µA of current.”