Shared by SethB62 on Instructables:
This project will make a button switch that will both boot up and shutdown a Raspberry Pi and will light an LED while the RPi is operational. Great for headless setups. I created it to augment a Raspberry Pi Baby monitor, because of the concern with using a camera in a shared room.
My example is on a Raspberry Pi Zero, but it will work on any Raspberry Pi.
The button switch is just Pin 5(GPIO3) and 6(GND) connected together. I added a .01uf capacitor because it would signal the GPIO without hitting the button especially when I discharged static electricity nearby. Works reliably with the capacitor.
The LED is hooked to ground with a 330 Ohm resistor and is powered by the TXD (Pin 8). It needs serial console enabled to Light up. My circuit board pictured is a little different from this guide because I was in the process of adding some IR LEDs to my project.
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