A very simple systemd service for Raspberry Pi that supports a configurable software-controlled hardware button, allowing to perform different actions for different hold times of the button, for click and double-click events.

Default behaviour in response to button activity is:

• Upon short click of the button: the HDMI (TV) will turn off
• Upon short double-click of the button: the HDMI (TV) will turn on
• Button held down for more than six seconds and then released: Raspberry Pi will reset, after playing a short chime ('reset.wav')
• Button held down for more than nine seconds and then released: Raspberry Pi will shut down, after playing a short chime ('shutdown.wav')
• Beep sound will be played every second the button is held ('click.wav'), until the highest defined limit is reached

By default, the software assumes the switch is connected to pin BCM 27.

All of the above is configurable by changing the 'config.json' file.

The default configuration supports the above, but everything is configurable.

{
        "hardwareBCMPin": 27, 
        "clickAction": "/usr/bin/tvservice -o" , // optional. The default action is- Turn TV off
        "doubleClickAction": "/usr/bin/tvservice -p;chvt 6;chvt 7", // optional. The default action is- Turn TV back on
        "timedActions": [
                {
                        "name": "Reset RPI", // informational only. unused
                        "elapsedSeconds": 6,
                        "sound": "reset.wav", // optional
                        "action": "/sbin/reboot"
                },
                {
                        "name": "Shutdown RPI", // informational only. unused
                        "elapsedSeconds": 9,
                        "sound": "shutdown.wav", // optional
                        "action": "/sbin/poweroff"
                }
        ],
        "clickSound": "click.wav" // optional 
}

• A Raspberry Pi (tested on a model 2B, 3B and Zero, and on a model B after minor software modification)

• A normally open, momentary contact button. I use surplus ATX power buttons (as used on desktop PCs), as they're cheap and come with a handy set of wires and header connectors. Virtually any button will do the job, though. Just make sure it's normally open (push to close).

• A Debian-based operating system that uses systemd (tested on Jessie and Stretch)

• the python3-gpiozero package to provide GPIO Zero (tested on version 1.4.0)

Connect the button between GPIO 27 and GND. If you use an ATX power button and a Raspberry Pi with a 40-pin GPIO header, connect it across the seventh column from the left:

            -
· · · · · ·|·|· · · · · · · · · · · · · 
· · · · · ·|·|· · · · · · · · · · · · · 
            -

This shorts GPIO 27 (physical pin 13) to ground (physical pin 14) when the button is pressed.

GPIO 27 is not exposed on the original Raspberry Pi header, so GPIO 17 is a reasonable option. If you use an ATX power button and a Raspberry Pi with a 26-pin GPIO header, connect it across the fifth and sixth columns of the second row:

. . . . ._. . . . . . . .
. . . .|. .|. . . . . . .
         -

You will also need to change line 7 of shutdown_button.py to read:

use_button=17

git clone https://github.com/eric-h-st/rpi-switch-actions rpi-switch-actions

The software is installed with the following commands:

sudo apt install python3-gpiozero
cd rpi-switch-actions
sh install.sh

You can use 'sh install.sh' to re-install, if changes are made, such as- replacing sound files or for configuration changes

Enabling the service should produce output very similar to:

Created symlink /etc/systemd/system/multi-user.target.wants/shutdown_button.service → /etc/systemd/system/shutdown_button.service.

You can check the status of the program at any time with the command:

systemctl status shutdown_button.service

This should produce output similar to:

● shutdown_button.service - GPIO shutdown button
   Loaded: loaded (/etc/systemd/system/shutdown_button.service; enabled; vendor 
   Active: active (running) since Sat 2017-10-21 11:20:56 EDT; 27s ago
 Main PID: 3157 (python3)
   CGroup: /system.slice/shutdown_button.service
           └─3157 /usr/bin/python3 /usr/local/bin/shutdown_button.py

Oct 21 11:20:56 naan systemd[1]: Started GPIO shutdown button.

If you're seeing anything other than Active: active (running), it's not working. Does the Python script have the right permissions? Is it in the right place? If you modified the script, did you check it for syntax errors? If you're using a model A or B with a 26-pin GPIO connector, did you make the modifications in the Python script to use GPIO 17 instead of 27?

The output from dmesg will show you any error messages generated by the service.

Also, for a more coherent report, you could go to the system logs in /var/log/syslog

If you use a HAT/pHAT/Bonnet/etc. with your Raspberry Pi, check pinout.xyz to see if it uses BCM 27. If you do need to change the pin, best to pick one that doesn't have a useful system service like serial I/O or SPI. If you're using an ATX button with a two pin connector, make sure you choose a pin physically adjacent to a ground pin.

You should not need to reboot to enable the service. One machine of mine — a Raspberry Pi Zero running Raspbian Stretch — did need a reboot before the button worked.

The reboot code is based on the Shutdown button example from the GPIO Zero documentation.

This is not the only combined shutdown/reset button project to use GPIO Zero. gilyes/pi-shutdown also does so, but pre-dates the implementation of the various hold time functions in GPIO Zero.

GPIO 27 was used, as it's broken out onto a physical button on the Adafruit PiTFT+ display I own.

From GPIO Zero's pinout command

   3V3  (1) (2)  5V    
 GPIO2  (3) (4)  5V    
 GPIO3  (5) (6)  GND   
 GPIO4  (7) (8)  GPIO14
   GND  (9) (10) GPIO15
GPIO17 (11) (12) GPIO18
GPIO27 (13) (14) GND   
GPIO22 (15) (16) GPIO23
   3V3 (17) (18) GPIO24
GPIO10 (19) (20) GND   
 GPIO9 (21) (22) GPIO25
GPIO11 (23) (24) GPIO8 
   GND (25) (26) GPIO7 
 GPIO0 (27) (28) GPIO1 
 GPIO5 (29) (30) GND   
 GPIO6 (31) (32) GPIO12
GPIO13 (33) (34) GND   
GPIO19 (35) (36) GPIO16
GPIO26 (37) (38) GPIO20
   GND (39) (40) GPIO21

   3V3  (1) (2)  5V    
 GPIO0  (3) (4)  5V    
 GPIO1  (5) (6)  GND   
 GPIO4  (7) (8)  GPIO14
   GND  (9) (10) GPIO15
GPIO17 (11) (12) GPIO18
GPIO21 (13) (14) GND   
GPIO22 (15) (16) GPIO23
   3V3 (17) (18) GPIO24
GPIO10 (19) (20) GND   
 GPIO9 (21) (22) GPIO25
GPIO11 (23) (24) GPIO8 
   GND (25) (26) GPIO7 

Eric H.

This project is based on a project by: Stewart C. Russell, with permission — https://github.com/scruss/shutdown_button