I fitted a house alarm system years back but stopped using it because it was ruling my life too much. Now use CCTV and a MotionEye at my front door.
Ref 1. the bell box I recall mine included a rechargeable battery and a little relay. While the system was powered the alarm was directly controlled by the control box and the battery got charged.
If at any time the bell box became isolated, typically a total power failure including a failure of the control box's own internal battery, or far more sinister, by some actor cutting the bell box cable prior to breaking in, the bell box becomes autonomous, the relay drops out and the alarm runs until the battery exhausts. Maybe check your bell box.
I included a key switch in my bell box and positioned it so that I could (just about reach to) disable it by reaching through an upstairs widow and useful while I was fiddling with it.
Ref 2. Consider using simple opto-isolators between your extensive wiring and the controlling Pi. It'll keep a lot of interference out and the small current required the drive the opto-LED will give a useful 'wetting current' flow around the circuits which will ensure better reliability.
Ref the six way cable: go for a common ground/0 volts system and drive the strobe and/or bell by dragging the power line to 12 volts or the reverse of this. If your bell box has a battery it has its own tamper system. You could always include a small continuous power load in the bell box and monitor the current to it.
Ref 1. the bell box I recall mine included a rechargeable battery and a little relay. While the system was powered the alarm was directly controlled by the control box and the battery got charged.
If at any time the bell box became isolated, typically a total power failure including a failure of the control box's own internal battery, or far more sinister, by some actor cutting the bell box cable prior to breaking in, the bell box becomes autonomous, the relay drops out and the alarm runs until the battery exhausts. Maybe check your bell box.
I included a key switch in my bell box and positioned it so that I could (just about reach to) disable it by reaching through an upstairs widow and useful while I was fiddling with it.
Ref 2. Consider using simple opto-isolators between your extensive wiring and the controlling Pi. It'll keep a lot of interference out and the small current required the drive the opto-LED will give a useful 'wetting current' flow around the circuits which will ensure better reliability.
Ref the six way cable: go for a common ground/0 volts system and drive the strobe and/or bell by dragging the power line to 12 volts or the reverse of this. If your bell box has a battery it has its own tamper system. You could always include a small continuous power load in the bell box and monitor the current to it.
Statistics: Posted by RaspISteve — Sun Jun 30, 2024 11:28 am