Support for the Pi-Desktop Power Button?

Hello community,

the Raspberry Pi (model 3B+) is an always-on board by design - it has no power button. This will make LE sending a permanent video signal to my TV. When I turn the TV on, it will instantly switch to the active video signal input (LE), and doesn't stay in TV mode. This is bad, and I want to find a solution.

The first idea was to temporary switch off the HDMI signal by the command "tvservice -o". Unfortunately the command to switch HDMI on again "tvservice -p" doesn't work on LE.

The next idea is to put the Raspberry Pi in a case with a power button. I have found the Pi-Desktop case by Element14 on the market. To make the power button work, it needs an additional Debian package "pidesktop-base.deb". The source code for this package is available on Github.

Is there any add-on or another solution to make the Pi-Desktop power button work on LE?

PS: I have been found this thread, which is still unsolved and has a "maybe too old" warning. If someone made it work from there, please give me a notice.

Quote from Iridium

You could try This to power on/off your device

I have been tried this, and it partially works. (edit config.txt, shortcut GPIO 3 and GND as power button)

The power on works fine.

The power off will let the shutdown menu appear (power off, power off timer, reboot).

Do you know a trick how to avoid that menu and instantly power off?

Quote from Iridium

This might also help

I followed those instructions and did that:

- set config.txt back to original (no "dtoverlay=gpio-shutdown")

- installed "Raspberry Pi Tools" from repository

- created the "autostart.sh" and "off-button.py"

- set both files as executable (chmod +x)

GPIO3 now still works as power on (it always does), but the next trigger to power off does nothing.

The python script ("off-button.py") looks OK:

- the necessary lib from "Raspberry Pi Tools" exists (/storage/.kodi/addons/virtual.rpi-tools/lib/GPIO.so)

- the pin mode "GPIO.BCM" is correct for my model 3b+ with GPIO3 power button

Any hints?

PS: The command line response when starting from ssh ("sh /storage/.config/autostart.sh") is this:

Traceback (most recent call last):
  File "/storage/scripts/off-button.py", line 6, in <module>
    import syss
ImportError: No module named syss

Still an error at line 6:

File "/storage/scripts/off-button.py", line 6
    import sys.path.append('/storage/.kodi/addons/virtual.rpi-tools/lib')
                          ^
SyntaxError: invalid syntax

Success! GPIO3 power on/off triggers the expected results now!

Thank you very much, Iridium!

I can use a cheap case now, and install my own power button - problem solved.