I want to add PIR sensors to 5 rooms in a house. Assuming I have the physical laying down of the utp cable figured out, how should I wire them in order to keep the number of UTP cables to a minimum.
At first I thought I needed 1 data utp strand per 1 data pin on each PIR. I thought I could hook up 8 PIRs per UTP cable, but then I realized that each sensor needs its Vcc and GND.
This means that I could only wire 2 sensors per UTP strand since I would need 3 wires per PIR sensor (Vcc, GND & Data)
I guess this is the best way to do this? Since the PIR sensors are in separate rooms, I cant very well wire the GNDs together along the way. I would need to bring each GND back to the main room and connect them at that point.
Ok Im not sure i follow, lets suppose I have 4 rooms, one in each corner of the house and a control room at the center. I would have to wire:
East Corner to Studio: 1xVcc, 1xGND and 1xData
and so on, for each room right?
Unless I ran a GND main wire and VCC main wire around the house for those PIRs to tap into:
So the first option, the one that looks like a star?
Determine a path for wire(s) that makes all sensors connect to each other and the central hub, with the least amount of wiring. Wires can be shared (e.g. central hub - sensor 1 - sensor 2 - sensor 3, another from hub to sensor 4, and then one more from sensor 1 to sensor 5).
Then figure out how many conductors you need in each section of wire. PIR sensors draw little power so can share VCC and ground. The signal output is one wire per sensor. Use the points where the sensors are as connection point between separate sections of wires, connecting Vcc and GND, and signals as needed.