A simple hardware device to remind you to standup after one hour, typically when you’re sitting all day at your office.
It is made of a LED, blinking once per minute. After one hour, it blinks repeatedly.
After another hour, it stays lit and finally, after some more time, turns off (device will sleep).
I’ve used an esp8266 because I had a bunch in my drawer but it’s clearly oversized for the purpose.
You can then press the button to begin a new cycle at any moment.