[Help Wanted] - Creating custom script accessing GPIO pins

[vader7071]

As I was preparing one of my ORP controllers, I remembered that the Pi isn't a huge fan of just being "turned off". It rather prefers to use a shutdown command. Thinking on this, I have built a hardware schematic to do the following:

• provide small battery backup power to the Pi
• monitor if normal power is available
• if power is lost, maintain uninterrupted power via the backup battery long enough to let the Pi go through its shutdown procedure
• once pi is shutdown, disconnect the battery so that when normal power returns, the pi will boot up, return to normal operation, and reconnect the battery.

Thing is, to do this, I need to monitor one GPIO pin as an input and trigger one GPIO pin as an output. I can write a script in Python (is there a better language for this?), but I'm just not sure how to access the necessary pins. Once I get that part working, I can work on developing this script to run as a service. I have an ICS 1x Pi board and an ICS 2x Pi board.

The follow-up question on this, has anyone already done this? If not, would this be a feature that others are interested in? I don't mind sharing once I get it up and running.

[abcrawford]

These types of devices have existed for a while.

Here is one video.
https://youtu.be/oyp-m4VzxwQ
Of course he notes on his that he's not certain that he got his script working properly.

And another similar video on a similar board:
https://youtu.be/p86AbqgRaIo
This one uses pogo pins and connects to the I2C interface from underneath.

Both these videos are a few years old but it seems there are numerous options already designed.

Here's an example script repo as well that mentions some shutdown options.

https://github.com/frtz13/UPSPlus_mqtt

Perhaps this will solve your problem or give you some more inspiration for your project.

Keep tinkering.

[vader7071]

@abcrawford, thank you. I found where I can modify the /boot/config.txt file and create a shutdown pin. According to the documentation, all I need to do is add

dtoverlay=gpio-shutdown, gpio_pin=4

to the config file and that enables GPIO-04 (physical pin 7) to be a shutdown signal when grounded. Looking at the ICS schematics and documentation, GPIO-04 is not used, so that should work. But it doesn't, for some currently unknown reason. I looked more at the 1X schematic, and the extra GPIO pins are listed as GPIO-496 through GPIO-503. Since GPIO-04 didn't work, I tried GPIO-496 on the GPIO expansion. That didn't work either. I also tried GPIO-17 (physical pin 11)