[Solved]My system is a motion detector alarm system. The sensor part of the system consists of 3 SR501 PIRs which will set off the alarm if any one of the sensors is triggered. The alarm part of the system consists of a floodlight and a horn. The controller is an Arduino Uno.
The sensors are powered by 5 volts from the Uno. The alarm devices are powered by 12 volts from the Vin pin of the Uno. The Uno is powered by a 12v converter which plugs into a 110 Vac receptacle. Power and ground are distributed to the 3 PIRs via a strip board.
The system was assembled and successfully tested in my house. However, the system is intended to be used in my front yard. So I moved all the hardware to a 110 receptacle that is located in the yard for exterior lights and power tools. The yard circuit is GFI protected. When plugged into this circuit, the system, which works perfectly in the house, is very erratic. I suspect the problem is electrical noise.
I believe the power can be smoothed out by adding some capacitors and resistors to the 5 volt part of the system, but I don’t know where to connect them, nor which sizes to use.
I have attached a schematic of my system.
Motion Sensor Schematic.pdf (17.9 KB)