Raspberry Pi Power Button Script

Raspberry Pi Power Button Script.md

Install Raspberry Pi Power Button Script

Make sure you have a raspberry pi. (This script is tested with the raspbian dist on a series 3 model B+)

DISCLAIMER: Look at the script for the PINS and PORTS used. You can change it in the section Configuration if you like.

1. Download the raspberry-pi-power-button-script.py script, name something like shutdown.py and put it somewhere publicly available.

2. Make script executable with chmod +x <absolute_path_to>/shutdown.py.

3. Create a service with sudo nano /lib/systemd/system/shutdown.service as root and with content:

[Unit]
Description=Raspberry Pi Power Button Script
After=multi-user.target

[Service]
Type=idle
ExecStart=<absolute_path_to>/shutdown.py &

[Install]
WantedBy=multi-user.target

4. Make service executable sudo chmod 644 /lib/systemd/system/shutdown.service, register it and activate it:

sudo systemctl daemon-reload
sudo systemctl enable shutdown.service
sudo systemctl start shutdown.service

5. After restart:

sudo systemctl status shutdown.service

6. Use disable and stop to turn it off.

7. Use journalctl -u shutdown.service -f to follow logs

How to use it

The script listens to a short press for shutdown and a long press for reboot. Look at the script to see the default value used for the long press and change it as you wish. (default: 3s)

Additionally, there is a timeout after which the press is cancelled to prevent accidental shutdowns and a possibility to cancel the action if required.

The script has also a rebound timeout integrated to smoothen the behaviour for cheap buttons ;)

Have fun!

Author: miaucl

raspberry-pi-power-button-script.py

#!/usr/bin/python
"""
Raspberry Pi Power Button Script.

Author: miaucl (https://gist.github.com/miaucl)
Description: This script listens to a power button connected on PIN XXX and enables shutdown and reboot functionality for a raspbian dist using python 2/3.
Setup: The PIN XXX is configured with a pull up resistor and should be connected to the GND PIN by a simple interuptor.

(PIN: XXX)          (PIN: GND)
   ___                 ___
    |        ___        |
    |_______/    _______|
             BTN

Standard:
PIN=29/PORT=5
GND=30
"""



import RPi.GPIO as GPIO
import subprocess, time, sys, syslog, os

#####################
### Configuration ###
#####################

# GPIO-Port of the PIN
# GPIO 5, PIN 29 (GND just aside on PIN 30)
PORT = 5

# Max limit for shutdown (in secs), should the button be pressed longer, a reboot takes place
T_REBOOT = 3

# Timeout for the button to disable the action
T_TIMEOUT = 6

# Debounce time for the button (in secs)
T_PRELL = 0.05

###############
### Globals ###
###############

# Timestamp of the button press
timestamp = None

######################
### Initialization ###
######################

# Get the uid to check the permissions
uid = os.getuid()
# Needs root permission to shutdown/reboot
if uid > 0:
    print ("Scripts needs root permission!")
    sys.exit(0)

# GPIO initializing, BMC-Pin number, Pullup-Resistor
GPIO.setwarnings(False)
GPIO.setmode(GPIO.BCM)
GPIO.setup(PORT, GPIO.IN, pull_up_down=GPIO.PUD_UP)

##########################
### Interrupt Routines ###
##########################

# Interrupt-Routine fuer die Taste
def buttonISR(pin):
    """Interrupt routing listening to button."""
    global timestamp

    # Button is pressed down
    if not (GPIO.input(pin)):
        syslog.syslog("Button down")
        # Start the press
        if timestamp is None:
            syslog.syslog("Start press")
            timestamp = time.time()
        # Restart the press
        elif time.time() - timestamp > T_PRELL:
            syslog.syslog("Restart press")
            timestamp = time.time()
        # Skip as it is probably a rebound
        else:
            syslog.syslog("\t--> Skip: Already a press in process and probably a rebound")

    # Button is released up
    else:
        syslog.syslog("Button up")
        # If a press is active
        if timestamp:
            # A press is completed
            if time.time() - timestamp > T_PRELL:
                syslog.syslog("Stop press after: {:.3f}s".format(time.time() - timestamp))

                # Reboot for long press
                if time.time() - timestamp >= T_REBOOT:
                    syslog.syslog('==> Shutdown: System rebooted');
                    subprocess.call(['shutdown', '-r', 'now'], shell=False)
                # Shutdown for short press
                else:
                    syslog.syslog('==> Shutdown: System halted');
                    subprocess.call(['shutdown', '-h', 'now'], shell=False)

                # Reset the timestamp
                timestamp = None

            # Skip as it is probably a rebound
            else:
                syslog.syslog("\t--> Skip: Probably a rebound after: {:.3f}s".format(time.time() - timestamp))


# Interrupt for the button PIN
GPIO.add_event_detect(PORT, GPIO.BOTH, callback=buttonISR)

############
### Main ###
############

syslog.syslog('Shutdown.py started');
while True:
    try:
        # Sleep
        time.sleep(1)
        # Reset the timestamp after timeout when active
        if timestamp and time.time() - timestamp > T_TIMEOUT:
            syslog.syslog("Timeout press...")
            timestamp = None
    except KeyboardInterrupt:
        syslog.syslog('Shutdown terminated (Keyboard CTRL+C)');
        print("Bye")
        sys.exit(0)