Garages and Carports - Add laser garage assist to Chamberlain

My Chamberlain has R-W-Bk terminals, with R-W for button and W-Bk for safety sensor connections. I presume the W-Bk are 12V, always on, with 1K/2K resistance for inactive/active, like an alarm sensor.

I have yet to hear from their tech support people, but how would these lasers work so that they turn on when the door opens and turn off a minute later, if the safety sensors are always energized?

I'm not sure how they work, I have only installed one set, And if i remember right it is not a constant beam but more of a flashing beam for a minute or two. Here is the owners manual http://www.dcsolutionsinc.com/consumerweb/pdfdocs/114A3174.pdf

It is an infrared beam between the two sensors. The beam doesn't turn on and off, it is always on but only affects the closing of the door. If the beam is interrupted while the door is closing it will reverse to the open position and the main light will flash 10 times. The brain in the logic board knows which direction the door is moving.

I'm not sure how they work, I have only installed one set, And if i remember right it is not a constant beam but more of a flashing beam for a minute or two.
I called Chamberlain. Apparently one of the terminals goes HI (or GND...or maybe changes resistance) at the same time the lights activate. This gives the laser power to activate, but the laser uses an internal timer to cycle OFF.

There must be more to it, though, because the security sensors still have power even when the light timer expires, preventing the door from opening if there is an obstruction etc.

Maybe I should take my Fluke and check the terminal voltages :-)

Sorry guys I was in the wrong garage I guess.

I thought they only controlled the door on the down stroke. Maybe there is some liability issue which made them add up stroke control.

Actually, why do you care if they are on or off, if they work correctly. Mine are LED's and are lit 24 - 7.

he is talking about an add on parking assist laser beams not the photo eye safety sensors

Looking at Doorman's instructions, I see that the power is always on, that the laser should blink for about one minute after the door starts to open. It then resets and can be tripped again by someone breaking the safety sensor beams.



Edited after looking at instruction sheet.

I checked the voltages across R-COM-Bk under both lights on and lights off scenarios.

There is a constant 16V (R-COM, door button) and 6V (Bk-COM, sensors and laser).

Beats me how the laser turns on when the door opens, unless there is a momentary voltage change.

Does the laser come on when you open the door and the car is not moving? Reason I ask is that the door obstruction sensors may be the trigger. If the door opens with no laser action and then, when you momentarily block the sensor, the laser starts flashing, you know the sensor is the trigger.

That would make sense..its a PARK assist..not a backing out assist...lol Why would you want it to come on every time the door was opened or closed unless a car was pulling in?

Perhaps this is how the laser knows that it should turn on: re-using a garage door sensor - Home Automation Forum , Home Security and Home Theaters (http://www.cocoontech.com/forums/index.php?showtopic=11014&pid=96038&mode=threaded&show=&st=0)