Wiring a WIFI relay to a garage door remote controller

Thread Starter


Joined Oct 22, 2018

Noob here so please be gentle,

I am wanting to put together a WIFI controlled garage door opener for home automation purposes.

All the info I’ve found on the web requires you to wire a relay into the garage door motor itself (which I don’t want to do) or to the wall mounted controller (which I don’t have).

So what I’m trying to do here is use a WIFI relay to trigger the open/close button on a spare remote controller, which I will mount to the garage wall.

The remote controller is an old school 27mhz type and has 4 push buttons, only one of which I will need to trigger (pictured below).

I’m guessing I’ll need to de-solder one of the clicky buttons (circled) and attach the relay to that. But there are 4 solder points on each button. The only other catch is that I will require “inching” as the button must be clicked and held for a second or so to trigger the door, then released.

I am hoping someone can please assist me with the following;

  • How and where to hook up the relay to the clicky button
  • Suitability of the relay in question
  • Anything to be aware of (putting too much current across the circuit via the relay etc.)

Here is the WIFI relay I was thinking of purchasing for this project which fits the bill for WIFI and IFTTT; (I have no idea about what the volts and amps mean or anything like that).


Here is the garage door remote (removed from its housing) I’ve circled the clicky button front and back that I will need to put the relay across.

Many thanks!


Joined Jun 19, 2012
1) no need to remove the existing button

2) with the power off, find which 2 switch terminals "short" when the button is pressed. (use ohm meter)
Most likely, across the short side of the switch. These switches have 2 redundant terminals, these will be always shorted.

3) almost any mechanical relay can be used to activate the input, but resist the temptation to run really long wires between the unit and relay.
(1 meter or less)
You can also use an OPTO-FET such as this http://www.onsemi.com/PowerSolutions/product.do?id=H11F1M

providing a 200-300 ohm resistor would activate the button.

Then all you have to do is activate the LED inside the coupler with 16 mA

What I have done is to use an LM334 current source, a diode, set to about 20 mA and you could use any 3.6 V (guess) to about 30 V source to activate.

I actually used these http://logosfoundation.org/instrum_gwr/playerpiano/Optor_VTL5C1_87223.pdf
they might require more current to activate.

You can also use OPTOMOS relays which are in about the same package, but lower on resistance.

S, the questtion is what;s the highest value resistor that will reliably activate the door. Pick a value smaller ans set the LED current ot about what you need.

The OPTOMOS relay needs only about 2 mA to work.

Thread Starter


Joined Oct 22, 2018
Thanks KISS for the reply.

I'm a bit more confused now about diodes and amps etc.

If I were to use the relay linked and pictured in my post, would I actually need to put diodes and capacitors and whatnot between the relay and the button terminals to regulate the amps? Or should it be fine to just run wires direct to the positive and negative of the button?

Again, apologies for the noobish questons
Use the simple relay, just connect it directly to the switch.
This does work, BUT it CAN have reliability problems because of what's know as "wetting current"

On a non-noble metal, oxides build up on the contacts when too little current is switched. The tact switches employ either non-metal and are designed to switch very little current.

The number varies, but the relay should have "wetting current" specified. Rule of thumb says 1-10 mA.

The small amount of switched current cleans off the oxides on the contacts.

The garage environment would probably be condusive to forming oxides.


The method I suggested is more complicated. It can be really small. The switched side can be much longer.
The diode just makes it a little polarity insensitive in case you hook it up backwards.


Joined Jul 28, 2019
I'm hoping that someone could quickly clarify a graphic instruction from a Chinese seller of a wi-fi smart switch garage door opener: https://eachen.cc/product/eachen-gd-dc5-ewelink/

The wi-fi switch is not directly compatible with my garage door opener but the company claims that a person could connect the switch relay to a garage door remote controller. I would like to use a standard Chamberlain remote control with the switch as explained below by the seller. The green bubble below is not self-explanatory to me. Would I have to de-solder the click button in the green bubble and solder the relay onto it or would a simpler approach exist?
What the seller is trying to say is that there is a "button" in the remote. You have to take the remote apart and locate the solder pads that are closed by the "switch". A conductive elastomer could be used or a switch like the one illustrated. With the switch illustrated, there are two "pin pairs". i.e. You only need to connect two of the pins.

De-solder - no.

Without an ohmmeter, just find the two pins on the switch when shorted together with a wire or paper-clip activates. You can solder to the top or bottom of the switch, whatever is easier. The green stuff is solder mask, Solder won;t stick to it. You can remove it with a razor blade to expose more area.

Fir reliable soldering, the manufacturer wants as little pad area to heat. The PCB is like double sided with plated-thru holes. Any connection on the front is on the back too.
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