Interfacing Elk with Genier Garage Door Sensor


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I would like to wire the Safety Beam sensor from my Genie Garage door to the Elk M1. Can this be done with a simple relay from the garage door keypad to the Elk?
Could anyone point me the in the right direction or can this not be done easily?

I would like to have the Elk make an announcement every time the beam was tripped. I'd rather not use a motion detector since I'm only concerned about someone action entering through the door rather than just being in the garage.

I have a sensor on the garage door to know when it's opened . .but we like to leave it open in the summer for ventilation.

Thanks in advance for the help. :)

I skimmed through that thread and didn't find a reference to the beam breaks token was wanting. Did I miss it somehow?
Sorry the beam part was not discussed but the garage door integration with elk was discussed in detail by spanky.

I hope that is the right thread.

I remember we discussed this here or on some other MB a few months ago. I think it was when Rupp had his beam fail.

There appears to be some sort of signaling between the beam receiver and the garage door opener as the beam assembly is required by law on new systems and the manufacturers enforce that. It could be something as simple as an end-of-line resistor, so it may be worth investigating with a meter or something. But the short answer is that it is NOT a simple relay that can be connected to the M1.
I did a very (i.e. may not be accurate) test on my Genie garage door opener and noted the following:

On the garage door opener there are terminal screws labeled 1, 2, 3, 4, 5, & 6. The beam sensors are connected to terminals 1, 2, & 3.

With the beam unobstructed the following DC voltages existed on those terminals:

Terminals 1 (-) and 2 (+) = 3.9 volts

Terminals 1 (-) and 3 (+) = 6.6 volts

Terminals 2 (-) and 3 (+) = 10.5 volts

With the beam blocked the following DC voltages existed on those terminals:

Terminals 1 (-) and 2 (+) = 3.9 volts

Terminals 1 (-) and 3 (+) = 7.85 volts

Terminals 2 (-) and 3 (+) = 11.75 volts

So it looks like there is a voltage difference of 1.25 volts between both terminal pairs 1 & 3 and 2 & 3 between unobstructed and blocked.

The Elk can measure analog voltages, but only at eight bit resolution and around 14 volt maximum input.

So doing the math (again quickly) you should be able to see:

1.25 * 256 / 14 = 22 count difference in the Elk, which should be feasible.

Of course some problems may still exist such as:
  • Long wire runs between the Elk and the garage door my induce noise and influence the voltage differential.
  • You have to make sure that the Elk or the wire runs DO NOT interfere with this critical safety feature of the garage door.
  • The beam break may be to quick for the Elk to register this voltage differential.
Of course YMMV on this one, but above all, whatever you do, make sure you thoroughly test the safety beams still work after you are all finished.


Those voltages don't look like a simple DC beam break. There must be something more going on like a modulated beam signal. Need to look at it with an Oscilloscope to see what the voltages are doing.
Yes, excellent point. Don't have a scope here though :eek: .

Just for grins I hooked it to zone 1 setup as an analog zone. I looked at the voltage levels (from the status of the RP software) and got 9.8 to 10.2 unobstructed and 11.7 to 11.8 obstructed.

I then had the wife walk in front of the beam while looking at those voltages and the system wasn't responding fast enough. I don't know if it was the software status updating or the hardware that was the slow point.

I tried setting a rule for that zone so if the voltage went above 11 volts a voice announcement would be made, but for the life of me I could NOT figure out how to establish a "whenever" rule for an analog input zone let alone perform logic/match functions on a voltage reading.

Perhaps you seasoned Elk programming gurus can help me out with this simple task!

Oh well, this idea sounds like it's just not going to work out.

BTW: I did also test the safety function with the garage door terminals hooked up to the Elk and all worked as expected.
Thanks for all the input guys.

It sounds like it may not be as easy as I had hoped.

Can anyone recommend another beam type sensor that would work with the Elk?

Thanks again,
I believe you can adjust the speed/sensitivity of the Elk analog inputs somewhere in RP, but I might be wrong. As far as I know, there are no WHENEVER rules which can be triggered by a voltage change (since it probably would take a lot of cpu power), but I am pretty sure David mentioned that you could create a rule, i.e., every 5 minutes, and then check if the voltage is < 11, but I can't find this functionality in ElkRP right now.

I am really eager to try this too now lol.
I made a rule that checks agains an analog voltage every N seconds. I wonder if you can set it every 1 seconds.

However if you want the system to react inmediately it is possible to create a circuit that reacts based on a rapid voltage change. I designed one several years ago - and do not remember anything. Probably you will need at least an Opamp (comparator), a capacitor (store current voltage) and resistor (to balance thw to two voltages after n seconds). Some of our electronics expert could expand if interested.

Using this ciruit you could setup the input as a regular non-alarm and the Elk would react instantaneously.