Smartifying my garage door

Overview

The basic idea behind the project involves adding a relay to the garage door opener (GDO) which can be connected into your smart home control software of choice. A relay is a simple switch that toggles between ‘open’ and ‘closed’ states. You can think of it like a light switch that you can control via a circuit. The relay i’ll be using (a Shelly 1) is able to toggle via wifi which is perfect for home automation. ¹

Once the relay is attached, you can toggle the GDO open and closed via the relay, which means you can open and close the door from your phone, or set up automations to open the door when you arrive home, or close it when you leave. The Shelly also has a switch input which you can use to detect the state of the door, so you can tell if the door is open or closed at any time.

To detect if the door is open or closed, we use a magnetic reed switch. This is basically a small piece of wire that is affected by a nearby magnet. When the magnet comes close, it connects the circuit and the relay can detect that the door is closed. When the magnet is far away, the circuit is broken and the relay can detect that the door is open. We can connect the switch to the Shelly, then place a magnet on the door to determine the closed state of the door.

Will it blend?

After researching relays, namely learning what they are and how to buy one, I decided that in order to continue with the integrating one the first thing I needed to work out was if I could actually trigger the GDO without a remote or the wall switch. If I couldn’t then this whole thing was dead in the water before I even started and I should just go back to opening the door with a remote like a pleb.

My garage door is thankfully not made by Chamberlain ², it’s a simple ‘old style’ model which i’m pretty sure is the exact same as every other one made before the year 2000 which has been rebranded.

Because my GDO is old style, it triggers an open or close action by shorting two contacts on the main circuit board. In fact, this is all hitting the wall switch does in this case. In order to find the correct contacts on the opener I had to first take it apart, then trace the wire running into the unit from the wall switch. After unscrewing the casing I was greeted with this sight:

As you can see, there is a white wire running into the GDO main circuit board is attached to two screw terminals. The other end of this wire goes through the roof and connects in to the wall switch. To test out if I would be able to manually control the door, I (very carefully) shorted the two terminals with a piece of (insulated) wire connecting to each terminal and the door opened! Success, which meant that I could move on to part 2 - wiring in a relay.

Prepping

Satisfied that everything would work in theory, I went ahead and ordered the things I would need to complete the project. Once they all arrived I decided to ‘breadboard’ it and test everything before going through the effort of the install.

So I cut the end off of the 12v adapter and exposed the ends of the postive and negative wires, and screwed them in the correct terminals on the Shelly according to the manual for 12v DC power. (Which was 12v+ and L terminals for the Shelly Plus 1).³

I then connected one wire from the reed switch to the SW terminal, and the other end to the L terminal and placed the magnet close to the switch.

Once everything was screwed in to the correct place, I plugged it in, crossed my fingers and hoped nothing was about to explode. Happily, everything seemed to work perfectly! Opening the Shelly app, I could see the new relay and get it up and running. I could successfully toggle the relay opened and closed (which makes a satisfying ‘clunk’ sound each time) and verified that the reed switch was working. I had to set the switch to ‘Detached’ mode so that the switch wouldn’t auto trigger the relay.

Since it all seemed to be working, it was time to install everything on the door itself.

Installing on the door

This part should have been straightforward, but ended up taking a long time because its hard to attach tiny wires with your hands held above your head while all the blood drains out of your arms.

I was a little concerned before taking off the GDO cover that I would be having to drill some holes for the wires, but handily the base plate of the unit had some premade holes wide enough for the cables. I made sure to unplug everything (safety first) and slotted the 12v leads through the first hole. I attached the leads to the Plus 1 just like I did on the exploded view on the carpet. I had to let it dangle at this point, but the wires and the attachment seemed solid.

Next, I had to attach the wires for the relay. I took some of the doorbell wire that I had bought for the reed switch, cut off about 3cm worth and stripped the ends, then attached one side of each to the shelly and the other to the same terminals that the wire from the wall lead to. I don’t think it matters which side goes where, so I just attached it as made sense with the physical layout.

From there, I needed to attach the reed switch wires in and run the switch out along the door belt track. It would have been simpler to attach the switch in closer to the opener unit and save running all that cable out along the track, but doing it like that has a small flaw. Since the switch would be attached close the GDO unit, it would mean that the switch is only triggered when the magnet attached to the track runs all the way to unit when the door is fully opened. Since the door should really counted as open at any point before it is fully closed, attaching the switch so close to the GDO would mean that we would have no idea if the door was completely closed or 90% open.

Shifting the reed switch to the end of the door track means that the switch is closed only when the door is fully shut, so if it is 10% open or 100% open, it registers as open. This is better for security because now we can be confident that when the switch says it is closed, the door is actually closed.

To run it out along the door chain track, I used the doorbell wire. After running one end into the GDO unit and attaching it to the correct terminals on the shelly, I ran the other end out to where the track head attached to the door at the fully closed position. Once I worked out roughly the correct length, I cut the wire and attached it to the switch wires. This was a bit shoddy, since I didn’t have a soldering iron or proper connectors and just wrapped the wires around each other and covered with electrical tape, but since I don’t expect it to be moving around at all, it should hold up okay. That being said, you should always joing your properly! Don’t do what I do, and frankly, don’t do what I say either - i’m just some guy, what do I know?

I gave the switch a quick test to see if the positions I had chosen would work okay, and if my awful wire-wrapping job would actually work. The shelly happily reported the switch state okay, so I continued. To finish up, I mounted the switch on the track using blu-tac, and mounted the magnet on the track head at 90 degrees with some more blu-tac. With the switch and magnet in place, I worked back along the track fixing the wire in place with even more blu-tac. Surprisingly the end result doesn’t look that terrible - like, it’s not great, but it could definitely be worse.

The final product

With everything in place, the only left to do was test it out. Clicking the button in the shelly app, the door opened! The switch reported that the door state had changed from closed to opened. Everything worked!

I went ahead and closed the unit back up, tucking the shelly up into the casing in its new home, and tidied up all the cables on the outside.

Great success!

Q and A

Closing thoughts

To go one step further, you can tie the shelly into homeassistant and automate the door to open. I now have it set to automatically open when I arrive home from work.

All in all, this is a pretty great project to get someone started with home automation, since it requires no soldering (unless you want to do a proper job), not much in the way of things to buy and is fairly safe if you stick to low voltage.

I would definitely recommend giving it a go yourself if you’re interested!