Add Sonoff ZBM5 light switch

[MindFreeze]

Proposed change

Add the detached relay and related entities for ZBM5 but there is a catch.
This switch has 2 modes because the neutral wire is optional. And if there is no neutral wire, detached relay is not supported. This can be determined from the "work_mode" sensor in this PR but I don't know how to conditionally add the detached relay entities only if work_mode=1
The Sonoff site says that detached relay is only supported when there is a Neutral wire provided but after testing with 2 dual switches, this seems to be false. It works fine without a Neutral. I only tested it with a 20W light though so it may not work as well with a smaller load.

Additional information

Checklist

• The changes are tested and work correctly
• pre-commit checks pass / the code has been formatted using Black
• Tests have been added to verify that the new code works

[codecov]

Codecov Report

❌ Patch coverage is 60.78431% with 20 lines in your changes missing coverage. Please review.
✅ Project coverage is 91.32%. Comparing base (aaf89ff) to head (b7091d0).
⚠️ Report is 1 commits behind head on dev.

Files with missing lines	Patch %	Lines
zhaquirks/sonoff/zbm5.py	60.78%	20 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##              dev    #4198      +/-   ##
==========================================
- Coverage   91.46%   91.32%   -0.14%     
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  Files         341      342       +1     
  Lines       11203    11255      +52     
==========================================
+ Hits        10247    10279      +32     
- Misses        956      976      +20     

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[Jolanrensen]

Hi! Thanks for taking the time to make the quirk :)

Personally I have the ZBM5-3C and -2C (Firmware: 0x00001003) and I'm running 2025.8 beta 1. I tried adding your version of the quirk to my Hass instance and while I am able to change the detach_relay_mask, the relay_x_detached only report "None".
I assume this is also why the 3 "Detach Relay" switches are disabled in the device.

Is there something I could test?

[MindFreeze]

That was an old version. On the latest, you shouldn't see a mask. Only switches. And they are disabled by default. You have to enable them.

[Jolanrensen]

@MindFreeze I meant in the "Manage Zigbee Device" screen, but gotcha, enabling the switches successfully allows me to toggle detach mode indeed!

I don't see anything being logged when I press one of the buttons in detached mode, though. Does that work on your end? Can you respond to any physical button presses?

[MindFreeze]

Yes. On my switches it works as expected. The button toggles the switch in HA without changing the state of the physical relay

[Jolanrensen]

Yes. On my switches it works as expected. The button toggles the switch in HA without changing the state of the physical relay

So, you get 3 hass switches per sonoff button?

• Detach Relay x Switch
• switch responding to physical button x
• switch corresponding to physical relay x

Might be slightly different on my end as I have the 120 version

[MindFreeze]

Yes. On my switches it works as expected. The button toggles the switch in HA without changing the state of the physical relay

So, you get 3 hass switches per sonoff button?

• Detach Relay x Switch
• switch responding to physical button x
• switch corresponding to physical relay x

Might be slightly different on my end as I have the 120 version

No, I get 2 switches per button. 1 for the button/relay and 1 to detach the relay. It works as described in zigpy/zigpy#1612 (comment)

[Jolanrensen]

No, I get 2 switches per button. 1 for the button/relay and 1 to detach the relay. It works as described in zigpy/zigpy#1612 (comment)

Ah I see :) They have an "Opening" sensor that changes state whenever detached mode is enabled and a button is pressed. I also have an ZBMINIR2 where this works as expected. Unfortunately, there's no sensor for my ZBM5-3C-120, so there's no way to detect a button press in detached mode :/

I was kind of expecting that it worked similarly to my Aqara Switch. This doesn't have a "sensor" in detached mdoe, but it simply fires events whenever a button is pressed or double-pressed, which you can hook into in automations.

[sl33nyc]

FWIW, I successfully used this quirk from this PR after manually adding it to my 2025.8.0 installation. My use case is to turn one of the two available button+relay into just a button, while the other button+relay remains button+relay.

Yeah, unlike the ZBMINIR2, which I also have, there isn't a separate Opening entity.

where:

• Garage Door events represent just button presses.
• Driveway events represent button presses + relay on/off.

❗

[Jolanrensen]

@sl33nyc nice, but if you don't use the relay of the first button, then you don't even need detached mode, do you?

In proper detached mode, you should be able to handle the relays and buttons completely separately.
For example, you should be able to press button 1, and, using an automation, only switch relay 2 without changing relay 1. Or you could double-press button 2, relay 2 stays unchanged, but you turn on a completely different light in the house.

In my case, that's what I'm trying to achieve. The 3 relays all have lights attached to them, but a combination of presses, or a doublepress, should control all lights in my living room at once.

[MindFreeze]

These sonoff switches don't support that. I don't even see an output cluster for OnOff, so you can't bind it to a light, which is the original use case for detached relay.

[Jolanrensen]

@MindFreeze That's a shame :/ But I think you're right. Sonoff gives as a usecase: "With the detach relay enabled, smart lights won’t lose power when the wall switch is turned off, allowing them to remain smart at all times. *Supports connecting smart lights only in the neutral required mode." However, if you want to supply permanent power to a smart lightbulb anyway, why connect it to the smart switch in the first place? XD
Z2M also doesn't expose any actions (in contrast to my aqara switch).

I wonder if there's a way to differentiate between "turned X" and "turned X triggered by action" in automations... That would allow me to build a workaround in detached mode. Because "turned X" means a button press, which doesn't change the relay, and "turned X triggered by action" means an action taken by home assistant, which does change the relay.

Anyway, I'll figure it out. Looks like the PR can achieve everything that's possible :) thanks! For me it can be merged too

[0x55555555]

Hello,

I've applied this locally and tested Detached Relay mode works as expected.

Thanks,