Shutdown with terminal on rising edge of GPIO input

Question

I am trying to trigger my Raspberry Pi to shutdown on the rising edge of GPIO #4. I ultimately want to auto run this script on startup.

My python code is in file test1.py @ /home/pi

#!/usr/bin/python
print("Starting")
import RPi.GPIO as GPIO
GPIO.setmode(GPIO.BCM)
GPIO.setup(4, GPIO.IN, pull_up_down=GPIO.PUD_DOWN)
GPIO.add_event_detect(4, GPIO.RISING)
def my_callback(x):
    print("Event Triggered")
    command = "/usr/bin/sudo /sbin/shutdown -r now"
    import subprocess
    process = subprocess.Popen(command.split(), stdout=subprocess.PIPE)
    output = process.communicate()[0]
    print(output)
    x=1

GPIO.add_event_callback(4,my_callback)
print("End")

My terminal code is

sudo python test1.py

My output is

Starting
End

When I enter the above python code into Python shell, I get the above output and upon triggering GPIO4, it shuts down.

When I call it from the Terminal I get the above outputs but upon triggering GPIO4 nothing happens.

What am I missing so this will work from the terminal screen?

Answer 1

Your script seems to exit directly without waiting for an event. You may want to use a function that blocks the script until an event happens.

if GPIO.wait_for_edge(4,GPIO.RISING):
    my_callback()

at the end of the program will block the thread until an edge is detected. You don't seem to need x in the function so I just omitted it. There is also no need for GPIO.add_event_detect(4, GPIO.RISING) and GPIO.add_event_callback(4,my_callback) with this change