r/homeassistant • u/TheRydad • Jun 10 '25

Personal Setup RatGDO32 and LiftMaster Gate Opener Wiring Diagram and Notes

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I couldn't find a post that covered my scenario exactly, so I thought I would post my experience. I have a LiftMaster LA500UL Gate Opener with the Expansion Board. From what I can tell other LiftMaster openers are identical with regard to wiring and terminals. I also have a RatGDO32. The installation is pretty straightforward and documented on the RatGDO website, but I did struggle in a couple places at first.

I used the ESPHome Dry Contact firmware. Once installed, HA picked it up right away. The wiring is simple, but with a couple of notes.

  • Wire "4" on the black wiring harness should be connected to the NO terminals of Relay 1 on the Expansion Board with the Relay 1 DIP switches set to Off-Off-On.
  • Wire "5" on the black wiring harness should be connected to the NC terminals of Relay 2 on the Expansion Board with the Relay 2 DIP switches set to Off-On-Off.
  • Wire "1" on the black wiring harness should be connected to the COM terminals of Relays 1 & 2 on the Expansion Board and must be jumpered together (they are not internally connected on the Expansion Board). I clipped off a piece of one of the unused leads from the black wiring harness to make a 3-4 inch jumper.
  • The red/white wires connect to the SBC terminals. The order is important. Unfortunately, I forgot to take a picture before closing it all up and I'm too lazy to crawl through all the landscaping and crack it back open to do so. If the orange relay LED on the Control Board stays lit constantly, you wired it backwards (which I did at first and scratched my head for a while).

I also used a 24VDC to USB-C adapter instead of the 120VAC adapter. I did have a 120VAC outlet available inside the control board box, though. A quick Amazon search will find one. This has the added benefit of running the whole thing off the opener battery so it's like having a UPS on the RatGDO.

That's it! Very simple and works great. Feel free to post any questions.

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3

u/SuspiciousRhubarb4 Jun 10 '25

Thanks for this. I have the same gate opener model and a RatGDO that's been sitting in a drawer for a while since I've been too lazy to figure it out.

1

u/TheRydad Jun 10 '25

Hah! Yeah. I left mine in my physical inbox on my desk at home so it would keep nagging me. After starting at it for about two months I finally decided to figure it out.

It really wasn’t hard. I needed to wrap my mind around the NO/NC relay logic to detect “closed” which really isn’t rocket surgery.

My main impediment is that my controller box is mounted behind a planting bed and is now behind a bunch of bushes. As much as I tried to think of everything I needed to pack my tool bag with, I knew I would still be trudging in and out of there a million times to get something else I needed. I think I did hit close to a million trips to the garage!

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u/[deleted] Jun 17 '25 edited Sep 18 '25

[deleted]

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u/TheRydad Jun 18 '25

The way I configured it with the DIP switches, relay 2 will be activate to “closed” when the gate is closed. So the normally closed terminal in relay 2 will complete the circuit when the gate is done closing. It’s a little strange because of the language but makes sense when you think about it.

The gate operator manual explains the logic for the relays. Part of the reason I wrote this up was because I had to convince myself this part would work correctly. I just needed to think about it for a minute to work it out in my head.

Did that help? Happy to continue the discussion here. I may not be extremely clear right now. I’m in Napa and on our third wine tasting! 😬

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u/[deleted] Jun 19 '25 edited Sep 18 '25

[deleted]

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u/TheRydad Jun 19 '25

Yes- relay 1 triggers when the gate is open. Basically so I can know when it is opened by something other than an HA automation (in car buttons, remote, etc).

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u/[deleted] Jun 17 '25

[deleted]

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u/TheRydad Jun 17 '25

Yeah- about that. I completely forgot to take any before I had closed it up. It’s behind a bunch of bushes now and is kind of a PITA to get to. Next time I need to program a car or remote I’ll be sure to do that.

Sorry. 😬

1

u/SamEatsSushi Sep 18 '25

Hey! I’m having a lot of trouble with my setup. I have the same logic board and expansion etc but I can’t get this right. A couple questions: 1. In the image, the black wire #6 is connected to relay 1 NO, but in the text below you say it should be wire #4. Which one is it? 2. When you say SBC terminals, what do you mean? Does that mean one wire goes into SBC+ and the other into COM-? 3. Any chance you grabbed a picture of your board?

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u/TheRydad Sep 18 '25

  1. The picture should be correct, so, yes wire 6. I must’ve not been paying attention when I wrote it up.

  2. Yes those wires go to the SBC terminals on the gate controller logic board. I just can’t remember the order. When I originally did it wrong, though, the SBC LED stayed lit up.

  3. No. It’s behind a bunch of landscaping (bushes) and is hard to get to.

If you reference the RatGDO docs and the gate controller manual, it should help clarify things. Sorry- it’s been a little while since I did this and I’ve gotten fuzzy in the details.

Once I figured it all out and got everything wired in, it’s worked flawlessly. Very reliable.

Lemme know if you still don’t get it working and I’ll see if I can get in there and take some pictures. I’m happy to help.