Hand dryer

A hand dryer: a PIR motion sensor (OUT on GPIO4, 5 V) and a fan behind a high-trigger relay on GPIO26.

The fan runs while the PIR output is high, and keeps running for 2 s after it goes low to dry the last drops.

The test waves a hand at 1 s. The PIR holds its output high for about 5 s after the last motion, so it goes low around 6.5 s and the fan should stop around 8.5 s.