From 1a2c39d186bddea224ac3c3fde59ebbd74e9bd8a Mon Sep 17 00:00:00 2001
From: Toni Lekic <96660920+tonilekic@users.noreply.github.com>
Date: Mon, 30 Sep 2024 20:30:37 +0200
Subject: [PATCH] fix: add a custom function for polling the switch

The original script throws a RuntimeError on a RPi4:
GPIO.wait_for_edge(3, GPIO.FALLING)
RuntimeError: Error waiting for edge.

This is due the wait_for_edge function that is not compatible with newer python versions.

This commit will add a function that polls the corresponding GPIO input.
---
 listen-for-shutdown.py | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/listen-for-shutdown.py b/listen-for-shutdown.py
index cecc42b..eb6e162 100755
--- a/listen-for-shutdown.py
+++ b/listen-for-shutdown.py
@@ -3,10 +3,16 @@
 
 import RPi.GPIO as GPIO
 import subprocess
+import time
 
+switchPin = 3
+
+def wait_for_falling_edge(gpioNumber):
+    while GPIO.input(gpioNumber):
+        time.sleep(.01)
 
 GPIO.setmode(GPIO.BCM)
-GPIO.setup(3, GPIO.IN, pull_up_down=GPIO.PUD_UP)
-GPIO.wait_for_edge(3, GPIO.FALLING)
+GPIO.setup(switchPin, GPIO.IN)
+wait_for_falling_edge(switchPin)
 
 subprocess.call(['shutdown', '-h', 'now'], shell=False)