Last week I was curious about the signaling used by my garage door opener to its wired remote. My garage door opener has a wired remote panel with three functions:
Below are scome oscilloscope shots with my comments of how the signalling works in case someone else out there is also interested. The motor control units sends an inverted periodic pulse train. The multiple functions are controlled via modulating the pulse width.
This data might be interesting if you wanted to add an RFID keypad, improved & more satisfying wired panel, or BLE keypad. Find me on Twitter @roteno if you build something & found this useful.
IDLE STATE - normal state of the system while unlocked & not being operated by a user
Period: 12mS Vmax: 24V pulse width: 190uS
IDLE LOCK STATE - puts the system into a idle locked state that disables the wireless keypad open/close door functionality. Wired door open/close functionality continues to work.
Period: 200mS Vmax: 24V pulse width: 100mS (idle state 12mS period & 190uS pulse width are pressent as well)
LIGHT ON / OFF - toggles the internal light on & off
Period: 12mS Vmax: 24V pulse width: 2.6mS
LOCK ON / OFF - toggles the lock state on & off
Period: 99mS Vmax: 24V pulse width: 24mS
DOOR OPEN / STOP / CLOSE - toggles system between open garage door, stop door movement, close door
Short the two wires. Pulse width > 200mS.