Garage door safety sensor wiring?

I believe it is an infrared sensor with two wires on each. I have wired them to a 120V plug and the LEDs on them turn on and my motor spins slightly (probably just because it is a 120V motor and it's not getting enough electricity) but I try to line up the sensors and they do nothing different even when crossed. What I want to happen is for the motor to remain off until the beam is crossed. Once crossed I want it to spin and to keep spinning until I disconnect it. I would really like to put an alarm on it so when crossed an alarm goes off. Does anyone know the additional things I need and how to wire them? Thanks

iceng5 years ago
If the door sensors are trip switches.  .  . A
frollard5 years ago
Goodhart has the answer, in all the ones I've seen its an infrared emitter on one pair of wires (going to one side)

...and an infrared phototransistor on the other side, other 2 wires...

It won't be enough current to power a motor through the sensor, but you should be able to see a difference in conductivity on the receiver side... (usually the larger box, often has an indicator led on it showing its receiving signal from the transmitter side.
Goodhart5 years ago
Well, that all depends on what kind of "safety sensors" they are. Switch type (hit a bumper and it stops closing), movement sensing, or visual obstruction (sees something in the way). You will need some more circuitry to get it to work though. If the sensors simply send a signal to "something" to activate, say, a switch that reverses a motor, the motor has to be reversable, and that something has to be able to make the polarity switch.