I found it. The alarm panel used a separate wire to provide +12V from another terminal on the panel to one of these alarm contact terminals. The purpose of this is to provide power to the connected accessory (the phone dialer, in my case).
Oooff, this was providing +12V to the GPIO pin on the Raspberry Pi!![:(]( "Sad")
After removing that +12V wire from the alarm contact, it started working as expected. When the alarm is triggered, the contacts close and I see this in the Digital Input in the software. When the alarm is cleared, the contacts open and I see that in the Digital Input in the software.
Lesson learned - make sure you know what you are connecting your GPIO pins to!
Oooff, this was providing +12V to the GPIO pin on the Raspberry Pi!
After removing that +12V wire from the alarm contact, it started working as expected. When the alarm is triggered, the contacts close and I see this in the Digital Input in the software. When the alarm is cleared, the contacts open and I see that in the Digital Input in the software.
Lesson learned - make sure you know what you are connecting your GPIO pins to!
Statistics: Posted by MarkEHansen — Thu Jan 02, 2025 4:44 pm