In this case, [Tod] wanted to use a momentary tactile switch to turn something on and off. Instead of going with a microcontroller he built the circuit around a 555 timer .

The timing interval of this timer is thus T=–1.1C 2 R 3 R 1 /R 2. Using appropriate values, you can obtain long time delays that you can't attain with the basic 555 circuit. But the real innovation ...

My favorite smart switches are getting a useful upgrade (one they should’ve already had!).A new Auto-Off Timer in the Lutron app lets you set the switches to turn off a set amount of time after ...