Last Friday I got some spare time (finally!) and, with the help and tools of my friend Alfredo, we placed a button in the RaspberryPi case so, when I push it, a custom command its executed on the RaspberryPi, like for example, a clean system shutdown.
We mainly followed this post, but used a different GPIO port, we soldered the components (once we tested the schematics on a protyping board) and modified the code to launch a custom command. This is the resulting code we used to do a system shutdown (I removed some comments from the original code of the post):
|
import os
import time
import RPi.GPIO as GPIO
GPIO.setmode(GPIO.BCM)
GPIO.setup(4,GPIO.IN)
prev_input = 0
while True:
input = GPIO.input(4)
if ((not prev_input) and input):
os.system(“sudo halt”)
prev_input = input
#slight pause to debounce
time.sleep(0.05)
|
The line highlighted is the one you should modify to set your custom command. To test it, you have to execute it as root:
|
1
|
$ sudo python gpio_button.py
|
and press the button. Finally, to launch this code in the startup process, just add it to /etc/rc.local (just before the exit 0):
|
1
|
$ sudo vi /etc/rc.local
|
Easy peasy!
For more detail: RaspberryPi shutdown button
