Control Liftmaster LA400 Gate Opener via HA?

@Pauldy still mucking with the setup for something that should be simple like you said. Either I am missing something, or my boards are not working. Below is what I have tried already in case someone comes across this thread for getting SBC.

I have 3 ratgdo purchased for 3 different dates. 2xLA500 dual arms, and 1xLA400, single arm.

I installed two of them, and one I am using for bench testing to figure it all out.

Trying to reverse engineer some of the wiring diagrams to understand them. In my opinion they are not clear. I contacted the seller by email, no response.

First on the black wire connector:

The black wire connector is labeled trigger. If I ground the pins labeled Open and Close, I see the HA status in the diagnostics section. These work also on my 2 installed ratgdo.

I also grounded the wire labeled Light, and I see the diagnostics input in HA turn on. So the light input works also. In fact, when I grounded the light wire, I can see the Diag Light turn on, AND the Controls section Light come on. So this logic works and confirmed.

What is left is to figure out what triggers the button control and associated info. I am not sure if I am missing the detailed documentation anywhere. If I am, please someone point it out.

So the large Blue connector, where it says Wall mounted button; if I connect the two inputs (to simulate a momentary button press on the wall), I do not see anything change. The diagnostic input does not change states (I expect it to if this is supposed to be the input to the ratgdo).

I am also trying to figure out which two outputs short when the Toggle door control is pressed in HA. I assume this is what emulates the wall button press. Again an assumption from my side.

So the questions remains:

  1. What is the wall button input to the ratgdo board?
  2. What is the SBC output from ratgdo to go to the SBC input of my control board?
  3. What is the Lock remotes control do? What signals on the ratgdo board does it control? Is this for an aux gate lock that connects to the actual gate controller?
  4. What are the other signals and how are they used?

Again, if there is a place where all this is documented, I would love to get the link so I can fully utilize the ratgdo module.

@acs540 did you figure it out?
Specifically the SBC part? I am still not able to get the door controlled from ratgdo.

And now the ratgdo keeps the door status open, even if the dry contact close is ON, meaning door is physically closed. Even if I change the cover to closed, it doesn’t update, keeps saying Open.

I spent some time with mine the weekend before last and got it working. I hooked up the open/closed sensors to the relay and set the dip switches on the expansion board. Then I measured the SBC on the expansion board and saw it was like 12v so I looked at the voltage on the main board and it was 3.3v so I hooked up the sbc to that. I hooked up a buck converter to the supply line and dialed it into 3.3v fired it up connected to the ap set it up to my homeassistant and wireless network and it worked as expected. Below is my test fitting before I 3d printed some cases and buttoned it up.

@Haze, I do have an expansion board. I confirmed that the relay setups work for the expansion board. When the gate is closed, the dry contact shows the “dry contact close” is ON. And when the gate is fully open, the dry contact shows the “dry contact open” is ON.
The main board SBC contacts must be working since the gate does open and close a few times when the Ratgdo boots up. The “toggle” doesn’t work once it fully boots.

When gate is fully closed,
ratgdo webpage shows the Dry contact close as ON and Dry contact open as OFF

When gate is opening,
ratgdo webpage shows the Dry contact close as OFF and Dry contact open as OFF

When gate is all the way open,
ratgdo webpage shows the Dry contact close as OFF and Dry contact open as ON

Toggle doesn’t work as you see on the right.

I see the same behavior. Dry contacts work the same as you describe.
Toggle does not work either.

Do you happen to have a wall button? The setup I am trying to achieve is:

wall button → ratgdo → gate SBC

That way I can use the wall button, or HA to open and close. Not sure if this is possible as I have not been able to get the ratgdo → gate SBC working yet and there is limited information and documentation on the workings of the module.

If my setup does not work, but I can get the ratgdo → gate SBC working, then I will need to put a zigbee or some HA input button to trigger the door off a wall mounted button press.
At that point, it is no different than what I had before purchasing the ratgdo which is disappointing.

I don’t have a wall button for the gate. I’m using an Adaprox fingerbot glued to a remote to be able to open and close the gate away from using MyQ for now.

Does SBC not require the mqtt firmware for Ratdgo? That could be your issue

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I just noticed the activity and was about to respond with that. I’m not sure the esp firmware will work for this just yet last I checked it was marked as coming soon. I am running the mqtt firmware.

asc500 your setup looks like it will work fine on the mqtt. The esp firmware is going to try and talk to the main board over the sbc port with the esp firmware and it’s just not going to work. Probably just open/close everytime you reboot it.

Ok. Will try again soon with MQTT. Thanks everyone

I just flashed the MQTT and configured it to see if it will solve my SBC issue.
I got only 2 message when it booted up, not 3.

I tried to test on the bench to emulate the relays coming out of my actual gate controller, so grounding the open and close, etc. I am not getting anything on the MQTT Explorer, and when looking at the device which was created in HA, also no change.
This is what I have in the HA device page:

Any ideas what to test next? Seems like no matter which way I go, something does not work. This should be an out of box function having paid for 3 of these boards. The integration with the gate controller should have been the hardest, but got those relays working and open and close status working. But basic function of the actual board is not even close to what’s advertised.

If I am doing something wrong, please highlight it. I have wasted countless hours trying to get something so basic working.

This is an LA400-CONT board. Ratgdo flashed with MQTT firmware and on dry contact (beta) config.

For the GDO red/white pair, on my board, there isn’t an SBC + and -, but rather an SBC and two COMM ports. I assume I connect to SBC and any one of the COMM ports. Is that right? That’s how I had my ismartgate hooked up, previously.

My issue is that I seem to have fried my ratgdo board as soon as I connect the red/white/black harness to the board. As soon as I connected the harness, the gate attempted to open, which I assume means the SBC temporarily shorted to COMM thus triggering the gate, but also killing the board.

Has anyone run into this before? I’m assuming I’m doing something silly here, but can’t seem to figure out where I’ve gone wrong!

So after finally getting this all setup… my control board broke and I had to get it replaced.

I now reconnected the control board to the expansion board and the RATGDO and I can get the gate to open and close BUT the status of the gate is ALWAYS CLOSING.

My setup is wired exactly to @HamBandit setup except that his setup appears to have wires from the Aux 1 and Aux 2 going directly to the ‘WAGO connector’. I think this is my issue as I originally thought this was a ground connector but must be something else.


In my diagram I have a single wire going from the middle connector of Aux Relay 1 to Aux Relay to like so:


Maybe this is my wiring issue and thus why I cannot obtain the correct status of the gate. Any feedback would be appreciated.

I am having a bear of a time figuring out where to connect to gate sbdc. I too have the RSL12UL. I purchased and installed the expansion board. I have most of the wiring ready as in the picture by HamBandit but can’t for the life of me figure out where to connect the Gate SBC + and -. We don’t have that on our board. Please help. I have the v 2.53 ratgdo.

Question: Are you saying the gate works, but HA will not determine whether the gate is open or closed?

Read the thread, to summarize where we are at this point:
MQTT works with dry contact firmware, but doesn’t say opening and closing without the accessory board
Esphome reads statuses but can’t open or close

So the current state of affairs is still that we have to use MQTT right? Just making sure I didn’t miss anything.

Now time for my noob questions…
The accessory board top two pins both read out 3.3 volts, can I use those to power the ratgdo? It stays pretty static through opens and closes (3.31v to 3.30v during movement).

Also, I have the 2.53i version… Just snip the exposed tips off the wire harness for the wires I don’t need for now?

Update, Did MQTT. On my 2018 board in the post above, I hooked everything up and my rate limit wires were different, for me yellow is opened and white is constant ground. I don’t have one at closed so debating my path forward. It seems to read ok except when power is reset. If the gate is closed it goes log crazy until it cycles once to know what position the gate is in. Debating on putting a cheap reed switch in vs getting the expansion board, unless anyone else has a creative suggestion!

Also in case anyone else is new to MQTT, I followed some guides online and getting the broker set up was easy but the ratgdo config field I think says “address” and host name does NOT work there, it has to be IP address. That was probably my biggest struggle.

And last update. I thought it was working with only the open sensor but it started log spamming after a bit when it didnt get the confirmation on the close. I caved and bought the expansion board.

One other thought though… Is it possible to use one of the other sensor wires for on-battery status? Thinking about leaving the open sensor I have on the lift arm, using one daughter board relay for closed and the other relay for battery status. The daughter board can do it but looks like the dry contact config only has the open and closed sensors.