Tuya MHCOZY Zigbee relay "Momentary mode"

I recently purchased a Tuya MHCOZY single channel Dry contact relay. I have wired it into a remote for my old garage door control. The description on Amazon says it has a “momentary mode”


MHCOZY 1 Channel DC 12V 24V AC 100-240V Tuya Smart Life app Dry Contact Zigbee Smart Relay Switch Module,Work with Alexa Google Home…

It is an isolated dry contact on/off momentary relay ZigBee board ZigBee IOT with clean contact low voltage Zigbee on/off switch controller,work as zigbee button to DIY Smart garage door opener with momentary mode

My question is does anybody know how to put this device in “Momentary mode”? I can’t find any documentation on this particular relay. The 4 Channel version has a “mode” button that supposedly allows you to change the mode of operation, but the 1 channel version does not have this “mode” button (or at least I can’t find it)

Hi @CovetousAutomaton

You can make a routine that when the relay is On then automatic shutdown after 1 sec

Yeah, I’ve done that, but was trying to get it to work natively (if possible). I found this on another forum pertaining to the four channel version:

It has 3 modes of operation, which is why I chose it. You cannot operate each relay in a different mode.

1: Each relay latches independently of the other. Good for lights.
2: Each relay independently makes a momentary (about a second) contact. Good for garage door button.
3: The relays latch opposite of each other. Good for ???

I have a 2 channel, not currently in use, and when I was playing with it I believe I was able to use the modes. I’ll try and pull it out tonight and see if I can identify the button, hopefully yours is in the same position.

Do the guts look like this (or similar)?


If so, then it’s actually an eWeLink device. I have one controlling garage doors, and they work great.

See the top button in the picture above? That’s the “change” button to go between a regular switch and a momentary switch. Press it once each time to toggle between the switch modes. When you’re in momentary switch mode you will see the little blue led come on and off twice (I think) and you will hear the relay close then open.

It uses ST’s standard Zigbee Switch edge driver. Here are the detail for how one looks in my environment:

Foyer chandelier cable lift control. One latches closed when the other latches open so you have direction control and don’t close two relays and try to turn the motor(s) improperly, depending upon the direction you want to go and the type of lift you have.

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I haven’t cut mine open to see what’s inside. Here’s what mine looks like:


The problem with using the one second method is that you have to say “Alexa, Turn opener two on” to turn it off. I know, minor semantics, but makes the “smart home” look pretty stupid. This is how I am operating it now.

It also has a “reset button” on top. I’ve toggled it but haven’t seen any difference in behavior.

BTW, I just ordered a couple of the 4 channel versions to see if they behave more as advertised.

Does anybody know if the 4 relays in the 4 channel version can go by different “names” in smartthings?

Do you have a Tuya hub? You might be able to change the settings in the Tuya app, then transfer the device back to SmartThings.

I have some common Tuya AC relays. I get the following options in the Tuya app, but no options to make these changes in ST.

Or, return that one and get this one that doesn’t need another hub: (if they meet your specs)

MHCOZY 1 Channel 5V 12V ZigBee… https://www.amazon.com/dp/B08X218VMR?ref=ppx_pop_mob_ap_share

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Mine is a bare board like the one John showed (just longer to accommodate a second relay); I haven’t seen the Tuya / enclosed version so not sure where they’re hiding the button…

You can create a custom Alexa routine with whatever key phrase you want, and have the action be “turn on opener two”. That would probably still apply once you figure out the momentary setting.

Please forgive the noob question (I’m only a few weeks into doing this), but how do you do this?

-Okay. The new 4 channel versions showed up.
Look like this:

The native driver only gives me this:

Is there a better driver that will give me more options?

Set up an Alexa routine, choosing “voice” as the event and enter the phrase you want to use. You can set up multiple phrase variations if you might have users who have trouble remembering the exact right wording. Then from smart home, choose the relay and turn it on/off as needed.

I’m using “SmartThings”, not “Smart Home”. Should I switch? Or have Both?

I just meant the category for actions in the Alexa routine. Once the device / skill is connected to your account it should show up there.

Sorry, I don’t see anything like that. Any hints?

From the start:

  1. Start a new routine
  2. Select “add an event”
  3. Choose “voice”
  4. Add your phrase/phrases
  5. Select “add an action”
  6. Choose “smart home”
  7. Select your device - I don’t know how you have it integrated so I don’t know what category it’ll show up under, but you should always be able to pick all devices and find it.
  8. Choose the action you need for the device - turn on, turn off, etc.

I thank you soo much Mark for your efforts here. What I am concluding is that "SmartThings is probably NOT the platform for me. I don’t have that option. Your Smart Home interface looks much more my speed.But doesn’t that mean I need a HA “server”? If yes, then I want to wait until I can get a Rasp Pi 5.

Sorry, I think we’ve been talking past each other. This is in the Alexa app, NOT ST. With SmartThings connected, all my devices are available there to create a separate kind of routine.