What does the PintSize.me HAT's button actually do when pressed?

[HanSooloo]

Checklist

• I made sure that there are no existing issues or discussions - open issues,closed issues,open discussion, closed discussion - which may answer my question or that I could contribute my information to.
• I have read the Known Issues Wiki Page and my question / issue is not listed.
• I have provided the version of the software and the operating system in my post.
• If I have an issue with genmon not communicating with the controller, I have read and followed the serial troubleshooting guide.
• I have included the generator make and model in my submission.

Version

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I have not submitted logs

What is/are your question(s)?

I am trying to understand what happens when the user presses the button on the PintSize.me HATs. I understand that it enables the user to connect to a setup SSID, save settings and reboot the Pi.
What I am trying to understand is how this is accomplished in details. How is this actually triggering a change in the way the Pi uses the WiFi and how the configuration files are changed.
Is it because the pre-installed Pi OS has listeners for certain GPIO signals and they, then, trigger a script to execute?
Just trying to get a better understanding of how the magic happens.

Additional information

No response

[skipfire]

@HanSooloo the PintSize software that's loaded into the pre-loaded units watches the button and utilizes the RGB LEDs for that. Going to a code level there is a button event listener that also starts a timer, if the timer expires prior to the button being released, then the software calls out to nmcli to do various functions, there is no direct editing of any wifi config files. The button could be repurposed for other uses, or if you have a 26-pin HAT in between it would just be disconnected with no adverse effects other than the button not being able to do anything. If the HAT/pHAT is on a system without the pre-loaded software it does nothing unless you add your own code into it.

[HanSooloo]

That's great .. thanks for the quick answer. Is there a GitHub repo of the pre-loaded software? Would love to look around and learn.
Great product and am ready to pull the trigger, as your solution makes it super simple to get it up and running.

[skipfire]

The software is not open sourced. The image itself has:
Raspberry Pi OS with GUI (Bookworm)
Log2Ram (reduces micro-SD usage)
GenMon
PintSize Configuration/Cloud Client - currently this is only available for pre-loaded and/or cloud subscribers.

[HanSooloo]

Related question .. couldn't find answers elsewhere. What is the purpose of the "Generator Splitter/Injector"? I have an Evoluion1 controller and have no intention of running anything other than Genmon on my Generac unit.

[skipfire]

The Splitter, Injector, and RJ45 kit all have a generator input and then split the RS232 and RS485 to different output ports so you can run genmon and a RS485 MobileLink at the same time. Beyond that, the RJ45 has a RJ45 output for the genmon side for doing a physically remote install (such as putting the Pi inside your house), and the Injector has a barrel input that can replace the 12v from the controller with the battery power on the Molex cable (configurable with switches on the injector & HAT) and then you only have to run the Molex cable to the HAT rather than Molex and power cables. If you are looking at the kits, the injector comes with the weatherproof case specifically for the cable management consideration, but for Evo2 users with WiFi MobileLink it can be used to keep that connected if the owner desires.