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How to control an electric garage door lock from an Elk M1 (or other) system


There is an abundance of Garage Door posts and some write up's about monitoring garage doors here on CocoonTech.com so I decided to document what I did for others to use, modify, copy, etc...

Disclaimer: This write up is for educational purposes only.

Here's the story: (No yawning please)

So...I just built a garage. I installed a Liftmaster LM3800 door Opener. It's great. It is a side mount (jackshaft) opener that works very well and is extremely quiet. It comes with an electric bolt that gets mounted on to the garage door track. The operator locks and unlocks the bolt. It works very well. So well that I decided to rip it a part and see what makes it tick as Liftmaster tech support was not very helpful. They had me on the phone for 45 minutes and basically made this locking device sound very complicated.

How to control an electric garage door lock from an Elk M1 (or other) system

What it comes down to is that the bolt is essentially a 12 volt automotive aftermarket door lock actuator similar to what would be used an aftermarket door lock install on a car, plus some metal parts, a spring, etc...

How to control an electric garage door lock from an Elk M1 (or other) system

I ordered a new replacement unit from an online source for about $37.00 plus shipping. The part number is 12-41A6102. This one even came with the two x20 button head screws (the website said screws not included) and a template for easy mounting.

I temporarily hooked up the replacement unit to the existing garage door operator. I tapped in to the bolt wiring and operated the garage door opener with a digital O Scope connected. The device operates on 13vdc from the operator and draws about 1.1 to 1.3 amps. The pulse is so quick that it was hard to get an exact maximum reading so give your self a little wiggle room with the amperage estimates.

I removed the bolt from the garage door opener and installed the unit on the workshop garage door that does not have an opener due to overhead space constraints. I followed the manufacturer's directions but I also added a few components.

I added a small reed switch and magnet to follow the status of the bolt. I used some self tappers to mount the magnet portion to the manual handle after flattening the opposite side (wall side) of the handle a bit so the magnet would sit flush on the black plastic piece. The picture shows the mounting holes and the magnet which is not mounted. If your screws are too long you may have to trim the bottom one down to be able to get to the Philips screw hidden behind the black manual operation handle. The hole to get to the screw is on the bottom. You don't have to take the handle mounting screw completely out to slide the handle off, just loosen it a bit.

How to control an electric garage door lock from an Elk M1 (or other) system

Once you install the magnet, temporarily mount the bolt on the door track. Then, connect the reed switch portion to a meter and find the best location on the wall to mount it so that it has continuity when the bolt is out or locked. The reed switch is normally closed with the magnet in place.

The reed switch wiring is tied to an Elk M1XIN input and set to Type 16 - Non Alarm. It is connected with an 18-2 cable. It's what I had available and a bit overkill for a contact status but it will work. Also, IMHO this monitored point should only be used as a bolt position monitor.

A proper overhead door contact should be used to monitor the actual door position or use the "Ultimate Garage Door Monitor" link at the end of this write up.

How to control an electric garage door lock from an Elk M1 (or other) system

I ran another 18-2 (power) from the Bolt to my Elk M1RB relay board that runs off the M1 main system board. You could also use a M1OVR. I would suggest using wiremold to conceal the wiring and a wiremold box to conceal splices in the wiring. What I did here is very temporary and I will eventually clean things up later after more time testing has passed.

How to control an electric garage door lock from an Elk M1 (or other) system

It takes two separate "Form C" relays to make this bolt work. One for lock and the other for unlock wired in a polarity reversing setup similar to what I remembered from my car alarm installation days years ago.

Set the relays up to be controlled from a Function key or however you need them to work. The key here is the timing. SET THE RELAYS' TIME FOR NO LONGER THAN 1 SECOND. If they turn on and stay on you may burn up the actuator and that would be a bad thing. Once the smoke comes out it's very hard to get it back in. I have tried getting the smoke back in on other projects. It doesn't work. I promise.

Here are the Elk Two rules that I use to make things work:

WHENEVER KEY F6 ON KEYPAD 1 ACTIVATES
     AND WORKSHOP BOLT IS SECURE
          THEN TURN WORKSHOP UNLOCK (OUT xx) FOR 1 SEC
WHENEVER KEY F6 ON KEYPAD 1 ACTIVATES
     AND WORKSHOP BOLT IS NOT SECURE
          THEN TURN WORKSHOP LOCK (OUT yy) FOR 1 SEC

(You may have to reverse the labels of the relays depending on how you wired the bolt)

This is the diagram of the relay wiring:

How to control an electric garage door lock from an Elk M1 (or other) system

For exact garage door position monitoring, BraveSirRobbin did a write up on the "Ultimate Garage Door Monitor" which you may find helpful.




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