Have a light only turn on while Retropie/EmulationStation is running

Triquick

Recently I bought the NES case for Raspberry Pi 3 from Old Skool Tools. I really like it and appreciate that it has a cutout to add a light to make it just like the original NES. In the past I have wired up a simple light but it would come on (and stay on) while the system had power, even if Retropie had finished shutting down and wasn't running.

What I really want to do is have a light come on while emulation station/retropie is running and shut off after its done shutting down (but the system is still plugged in). What is the best way to start?

edmaul69

@triquick wire the led to the bottom side of a usb port. The usb port shut off when you do the power down.

barrymossel

Maybe a PowerBlock circuit. The Pi can remain plugged while you can use a button to turn it on and off. The led will turn on and off with it (and even has certain patterns when booting and shutting down.

ortsac

@triquick I would suggest PowerBlock as well. Check it out on this site:
https://blog.petrockblock.com/2015/07/04/powerblock-another-power-switch-for-the-raspberry-pi/

Triquick

Would it be worth it to try to create a two scripts

One that turns the light on, and have the Retropie startup script call it?
One that turns off the light, and have the Retropie shutdown script to call it?

Or would that be to much of hassle dealing with updates to the startup/shutdown script?

Aryetis

Assuming that your led is powered by a GPIO pin you can write two quick programs with wiringpi to turn it on and off. Then call those programs using rc script : https://www.raspberrypi.org/documentation/linux/usage/rc-local.md

( I believe scripts for shutdown are at /etc/rc0.d )

Triquick

@Aryetis Great, thanks, that was exactly what I was looking for.