The Raspberry-Shutdown Project describes a very simple system in order to shut down Raspberry Pi safely. It consists of a Python 3.x script button_LED.py, a simple schematic and this description.
This project is tested in Raspberry models 3, 3B, 4B, zero-wh under Raspberry OS.
The python script uses the awesome libgpiod library
For older Raspbian OS consider unsing the deprecated script version
A running Linux computer should not be powered off without a controlled shutdown by the operating system, because this can result in damaging the file system on the SD_Card. Controlled power down is especially critical to achieve in so called headless systems with no monitor and keyboard. Raspberry computers do not provide a reset or power down switch. The presented solution allows initiating shutdown or a restart with a switch or an external signal. It also provides a hardware signal (e.g. LED) indicating the running operating system state.
On power up / boot
After Linux boot, a selectable port (default BCM21) is driven high and LED goes ON
Switch pressed > 2 seconds --> shutdown
Linux command 'shutdown -P now' will be executed by the script button_LED.py .
As soon as critical storage operations are completed, LED goes OFF.
Switch double clicked --> shutdown and restart
System shuts down and restarts.
Linux command 'shutdown -r now' will be executed by the script button_LED.py.
Switch pressed > 5 seconds (optional)
System shuts down and activates a selectable port until no more SD card access occur. This signal may be used in order to completely power down Raspberry by switching off the external power supply .
Restart after shut down
This is only achievable by external power off and on again.
(A much more convenient solution is using the UPS-2 project.
Project Components
- The python script button_LED.py
- A push button switch
- A high efficiency LED
- some wires
See user-guide.md