Q: I have a problem with an alarm system that trips every time the local police car pulls up in front of the store and uses their radio. It is not a wireless system, just a few motions and an alarm control panel. I really don’t want to pull out all the equipment. Any suggestions on how I can get rid of the false alarms?
A: Either you have a RF-sensitive device or you have some wiring that has a length and configuration that is making it act like a radio antenna. A couple of things you might want to try. If you have a motion detector, a glass break sensor, or other electronic device that is very close to the front of the store and the police car, you might want to try replacing just that unit first and see if it helps. You can also place some ferrite beads on the wire leads to help choke off any RFI that might be traveling on the wires. Make sure to wrap them around the ferrite ring a few times.
Q: I have a motion sensor in a small grocery store. Every time the pest control guy sprays the apartments above the store, I get false alarms that night in the store. The pattern is such that I expect the roaches are running from the apartments and across my motion sensor. What can I do to stop the false alarms?
A: Mount another motion sensor on another wall looking at the same area.
Wire the two sensors in parallel
so that they must open simultaneously for an alarm to sound. If a person walks in the area, they will both trip, but it is very unlikely you will get two bugs walking across both motion sensors at the same time.
