Add a physical shutdown button to a Raspberry Pi. This is particularly useful for a Raspberry Pi running in headless mode, since yanking out the power cord is not a safe option for shutdown. Choose between C, Python, or UNIX shell script implementations.

Hardware Requirements

• 1 Raspberry Pi
• 1 normally-open momentary pushbutton switch
• 2 jumper wires with female connector (only need if not already attached to switch)

If you need to connect the pushbutton switch with the jumper wires, you will also need a soldering iron and solder.

Software Requirements

• For bye_pi.py:
  sudo apt install python3-gpiozero
• For bye_pi.c and bye_pi.sh:
  sudo apt-get install wiringpi

NOTE: The project was tested on a Raspberry Pi 3 Model B running the Raspbian Buster Lite OS.

If the switch did not already come with jumper wires attached, solder two jumper wires to the switch. The two jumper wires should have female connectors on one end, so they can be attached to the GPIO pins on the Raspberry Pi.

There is more than one pin cominbation available for connecting the pushbutton switch. The code in this project uses physical pins 39 and 40, so unless you modify the code accordingly, stick with those pins. Keep in mind that the physical pin numbers are different from the BCM pin numbers, which are also different from the wiringPi pin numbers. The best way to visualize the relationship between the three different numbering systems is to use the gpio readall command.

Additionally, the pinout command shows each pins' physical orientation on the board as well as other useful information.

The setup instructions assume you have the script in your /home/pi directory, but if you have it elsewhere just provide the actual path to the file instead of /home/pi.

Make the Python script executable.
chmod +x bye_pi.py

Place the script in rc.local so it runs at boot. To do so, edit the rc.local file:
sudo nano /etc/rc.local
Add the following above exit 0:
home/pi/bye_pi.py &

Alternatively, you could use cron instead of rc.local to schedule the script to run at boot.
crontab -e
@reboot /home/pi/bye_pi.py &

Compile the C code to executable code.
gcc -Wall bye_pi.c -o bye_pi -l wiringPi

Place the program in rc.local so it runs as boot. To do so, edit the rc.local file:
sudo nano /etc/rc.local
Add the following above exit 0:
home/pi/bye_pi &

Alternatively, you could use cron instead of rc.local to schedule the script to run at boot.
crontab -e
@reboot /home/pi/bye_pi &

Make the bash script executable.
chmod +x bye_pi.sh

Place the script in rc.local so it runs at boot. To do so, edit the rc.local file:
sudo nano /etc/rc.local
Add the following above exit 0:
home/pi/bye_pi.sh &

Alternatively, you could use cron instead of rc.local to schedule the script to run at boot.
crontab -e
@reboot /home/pi/bye_pi.sh &

Connect the pushbutton switch to the physical pins 39 and 40. It is best to connect the switch when the Raspberry Pi is powered off.

Power on the Raspberry Pi. The script should already be running via rc.local or cron. Simply push the button to power off the Pi.