re-using a garage door sensor

[JeffCharger]

I have an old Stanley garage door opener that is broken, and I got to thinking that the safety sensors might be of use.... the sensor is the kind that has a light beam that is projected across the bottom of the door.

I don't know what the power source is, but I was thinking that there must be some way to power it, and then attach it to a powerflash unit to get a signal into HS. Anyone have any ideas?

 

[BraveSirRobbin]

Sounds like your system isn't operational . I was going to suggest just taking a meter and seeing what the voltage is giving you to the contacts on the opener unit.

I will try to do this during the weekend (if I remember).

 

[electron]

I think mine was 6 volts, don't remember, but I was under the impression that those sensors were more than just a simple NO/NC type sensor.

 

[gatchel]

I believe they work on different voltages similar to the way the door contol keypads have different resistances for open, light, and lock control.

 

[jharrell]

I believe they work on different voltages similar to the way the door contol keypads have different resistances for open, light, and lock control.

I always meant to look at them some more and see, as they would be a cheap beam break sensor.

If it's like door control it's not resistances but AC hackery using diodes (at least on the ones I have seen). The wire running to to door buttons is 12 or 24v AC, full short is open/close, one phase short is light, the other phase short is lock. Thats why normal relays patched in work fine to open/close from an automation system.

 

[JeffCharger]

Sounds like your system isn't operational . I was going to suggest just taking a meter and seeing what the voltage is giving you to the contacts on the opener unit.

I will try to do this during the weekend (if I remember).

BSR, I wish I had thought of checking the device out before uninstalling it all.... the base unit is broken, any testing anyone could do would certainly be appreciated.

 

[Lagerhead]

I have LiftMaster 1260s, 1995-era openers with factory-furnished obstruction sensors. Simple voltage measurements were not conclusive so I put a scope on it. Here is the result:

Safety sensors not connected -- the opener supplies continuous 6.25 VDC.

Safety sensors obstructed (violated) -- measured 6.25 VDC continuous across terminals, same as open.

Safety sensors not obstructed (secure) -- the sensors generate the waveform below. There is a pulse from 6V down to around 1V at roughly 6.8 millisecond intervals, or at a frequency of roughly 150 Hz.

I know this is not your opener make and model, but maybe you can look for the same kind of behavior in your sensors.

 

[JeffCharger]

I have LiftMaster 1260s, 1995-era openers with factory-furnished obstruction sensors. Simple voltage measurements were not conclusive so I put a scope on it. Here is the result:

Safety sensors not connected -- the opener supplies continuous 6.25 VDC.

Safety sensors obstructed (violated) -- measured 6.25 VDC continuous across terminals, same as open.

Safety sensors not obstructed (secure) -- the sensors generate the waveform below. There is a pulse from 6V down to around 1V at roughly 6.8 millisecond intervals, or at a frequency of roughly 150 Hz.

I know this is not your opener make and model, but maybe you can look for the same kind of behavior in your sensors.

Lagerhead, thanks for the info. This seems more complicated than what I was hoping for, and actually explains why I'd heard that they are proprietary. I was hoping that somehow I could just power it with a wallwart and connect it's output to a powerflash module to use as a driveway sensor or something. Feels like such a waste to sit in the "parts bin".