The best way I can recommend to do this does not utilize the arduino at all… If you know how to use a soldering iron then buy one SmartSense Multi for each zone and solder 26 awg wire (or one pair out of a CAT-5 cable) to both sides of the magnetic sensor then connect one side to common and the other to each zone trigger. This is much more reliable, bit less effort, and better integration with ST.
