How to connect a garage door photo eye to a micro?

I am looking at hooking up an old photo eye from a garage door to a micro. The end use will be in a device to detect if my dog is about to jump over the fence and take a picture as well as play some audio of me telling him to get down. The problem is that I don't know the correct way to connect the photo eye to the micro. I believe the transmitter site should be powered with 12V, but I would rather know for sure before frying the sensor. My garage door opener doesn't have a port for the photo eyes, so I can't check the outputs on it, but I was hoping someone here might already know, or might investigate their own open. Thanks for any help.

orksecurity5 years ago
If you're lucky, the widget is self-contained and already has a relay output; if so, it will be easy to adapt. If not, you'll have to determine exactly what circuitry it *IS* using and figure out how to get that to supply a low-voltage signal to your microcontroller.

Without knowing the exact model and having it and/or a schematic in hand, I don't think we're going to be able to give you much more specific advice than that.