Documentation for GPIO Buttons

[burberius]

I had problems with the modules MMM-Buttons and MMM-Button that they didn't recognize button presses or fired several presses. I think the Javascript onoff library to access the GPIOs is very bad.
My button (connected to GND and GPIO) worked without problems when using a simple python script!

So I found the following workaround as a replacement for the button modules:

1. install MMM-Remote-Control
2. add the button script printed at the end
3. add the following line to /etc/rc.local:
   python /home/pi/button.py &

Script

#!/usr/bin/python

import RPi.GPIO as GPIO
import urllib2
import time

# Button number in GPIO numbering
GPIO_BUTTON = 27
# Shutdown time in seconds
SHUTDOWN = 5
# Debounce time in seconds
DEBOUNCE = 0.15


GPIO.setmode(GPIO.BCM)
# Set pin as input
GPIO.setup(GPIO_BUTTON,GPIO.IN, pull_up_down=GPIO.PUD_UP)

# Initialize
start  = 99999999999999

# Callback-Function
def WORK(PIR_GPIO):
  global start
  if GPIO.input(GPIO_BUTTON):
    diff = time.time() - start

    if diff > SHUTDOWN:
      urllib2.urlopen("http://localhost:8080/remote?action=SHUTDOWN").read()
    elif diff > DEBOUNCE:
      urllib2.urlopen("http://localhost:8080/remote?action=NOTIFICATION&notification=PAGE_UP").read()
  else:
    start = time.time()

try:
  GPIO.add_event_detect(GPIO_BUTTON, GPIO.BOTH, callback=WORK)
  while True:
    time.sleep(60)

except KeyboardInterrupt:
  GPIO.cleanup()

Description
The script measures the time the button is pressed. On release it decides if it was a long press, which means a shutdown, a short press which means in my case send a broadcast to change the page or too short which will be ignored.
For shutdown and broadcast it uses the remote control http interface!

[burberius]

This is a suggestion for the wiki, I think adding it here is better than somewhere at the two button modules.
What do you think?

[edward-shen]

Just an FYI, you might get better feedback in those respective repos than here, since MM core can't really do anything about making sure modules well support the RPi platform.

[MichMich]

AS @edward-shen states, please open an issue in the respective repo's. Thanks.