Raspberry Pi RuntimeError: Conflicting edge detection already enabled for this GPIO channel

Question

I was following a tutorial found here: https://www.linkedin.com/pulse/prepare-your-raspberry-pi-work-aws-iot-kay-lerch

I have not even begun the internet part of it

Answer 1

Doddie's answer has the problem that the program exits after the first button press. Since the author mentioned an eternal loop, I would like to propose the following:

#!/usr/bin/python3

import RPi.GPIO as gpio
import time

pin = 7 

def on_pushdown(channel):
    print "Button Pushed."

try:
    # Setting GPIO layout
    gpio.setmode(gpio.BOARD)
    # Set pin as input pin pulled down to GND
    gpio.setup(pin, gpio.IN, pull_up_down=gpio.PUD_DOWN)

    while True:
        if not 'event' in locals():
            event = gpio.add_event_detect(pin, gpio.RISING, callback=on_pushdown, bouncetime=200)
        else:
            time.sleep(1)

finally:  
    gpio.cleanup()

If the button is pressed and an event is detected, the variable event is being deleted. Hence, the add_event_detect-function is not called twice in a row.

Additionally two things:

1. Depending on your setup, I would use a pull-up resistor. A pull-down setup is more prone to noise and an induction flank from somewhere might be interpreted as a button press.
2. Although this is not best practice: If your setup is really small (like inside the RPi case) and you don't accidentally set gpio.OUT and you just have a push button, you might consider to just take the build-in pull-up resistor and directly connect the push button to GND: GND --/ -- GPIO.IN (and then detect for gpio.FALLING).