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raspi-safe-shutdown

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Simple daemon service application for Raspberry Pi to handle a safe shutdown button with an indicator LED.

⚠ Disclaimer: I am not responsible for any possible damage caused to your boards.

Important: this has been tested on a Raspberry Pi 3 B with Raspberry Pi OS Lite (release date: 2024-03-12), and depends only on system packages (from APT). See install.sh for further details. If you want to double-check the versions of the Python libraries used, see requirements.txt.

Demo

Demonstration video (demo.mp4):

https://github.com/dmotte/misc/assets/37443982/3d33ca51-1fe9-4a12-b926-77b68fae8df9

Circuit

To use this application you just need to connect two components to your Raspberry Pi via GPIO: an LED and a button. However, I also find very useful to know when the board is powered and when the operating system is running. This can be achieved by connecting two more LEDs.

The ideal scenario is therefore the following:

  • The button should be connected to the GPIO_GEN0 pin (BCM #17)
  • The red LED (optional) should be connected to 3v3
  • it is ON when the board is powered, even if the OS is not running
  • The yellow LED should be connected to the GPIO_GEN1 pin (BCM #18)
  • it is the indicator LED for the raspi-safe-shutdown application
  • The green LED (optional) should be connected to the UART0_TXD pin (BCM #14)
  • it is ON only when the operating system is up and running

To make the (optional) green LED work as explained, you need to have Serial communication enabled on the Raspberry Pi. To enable it, log in and execute the following command:

Bash
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sudo raspi-config nonint do_serial 0

Then reboot the Raspberry Pi to make the changes effective:

Bash
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sudo reboot

Circuit diagram

Installation

Bash
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sudo RASPI_SAFE_SHUTDOWN_RESTART=when-changed bash install.sh