I am adding access control to the garage door of a residence that already has a Liftmaster (Chamberlain) unit in place. The idea is that a valid access will briefly energize a relay, which would be akin to pressing the wall button.
Foolishly, I thought that momentarily breaking the circuit (i.e, cause an open) between the existing switch and controller would do this, but that didn't work. I have since learned that the doorbell-style switch is not merely breaking the circuit, and the control panel is looking for a condition beyond merely a momentary open circuit.
Any ideas? My ultimate constraints are that the existing lighted-doorbell-switch still has to work, and that my method of control is a dry contact relay.
I see that someone had a similar challenge few months back.
Thanks in advance.
