Retropie GPIO control script

README.txt

# shutdown.py script to be at
/home/pi/scripts/shutdown.py

# Copy the unit file to
/lib/systemd/system/pi_shutdown.service

# ensure permissions are correct
sudo chmod 644 /lib/systemd/system/pi_shutdown.service

# To enable the service:
sudo systemctl enable --now pi_shutdown.service

# TODO: make an install script to do all this.

pi_shutdown.service

[Unit]
Description=GPIO Shutdown and Lights
After=Multi-user.target

[Service]
Type=idle
ExecStart=/usr/bin/python /home/pi/scripts/shutdown.py

[Install]
WantedBy=multi-user.target

shutdown.py

#!/usr/bin/python
import RPi.GPIO as GPIO
import time
import subprocess

GPIO.setwarnings(False)
GPIO.setmode(GPIO.BOARD)

# Set pin 11 HIGH to switch on cab lights
GPIO.setup(11, GPIO.OUT)
GPIO.output(11, 1)

# we will use the pin numbering to match the pins on the Pi, instead of the
# GPIO pin outs (makes it easier to keep track of things)

# DO NOT use the same pin that is used for the reset button as other shields are using the I2C pins. We will use a different
# pin to moinitor for the shutdown signal, but still use pin 7 to startup.
GPIO.setup(13, GPIO.IN, pull_up_down=GPIO.PUD_UP)

oldButtonState1 = True

while True:
    #grab the current button state
    buttonState1 = GPIO.input(13)

    # check to see if button has been pushed
    if buttonState1 != oldButtonState1 and buttonState1 == False:
        # shutdown
        GPIO.output(11, 0) # cab lights off
        subprocess.call("shutdown -h now", shell=True,
          stdout=subprocess.PIPE, stderr=subprocess.PIPE)
        oldButtonState1 = buttonState1

    time.sleep(.5)