Remote sensor in sonoff SNZB-02DR2

[nezteew]

Hi,

seems that the Sonoff SNZB-02DR2 thermometer also supports displaying values of remote sensors instead of the min max values.
I'm using Zigbee2mqtt in Homeassistent, but at least there the feature is completely missing.
Is there any possibility to add this?
So that I can send the values of the remote sensor to the Sonoff thermometer via mqtt and it is displayed there?

And also the firmware update does not work

[andrei-lazarov]

What do you mean fw update does not work? What't the error, some logs?

[nezteew]

This is the log. I also tried it a couple of times, also with clicking the button on the back to wake it up.

After clicking update on the OTA page:
z2m: OTA updating 'sonoff-temp-chaoszimmer' to latest firmware

After a while:
z2m: OTA update of 'sonoff-temp-chaoszimmer' failed (Device didn't respond to OTA request)

From time to time, independent of OTA update( od ist the id of the Sonoff):

zh:controller:device: Read response to 0xa4c13809c8f5ffff failed (ZCL command 0xa4c13809c8f5ffff/1 genTime.readRsp({"time":823812768,"timeZone":3600,"localTime":823816368,"dstStart":828061200,"dstEnd":846205199,"dstShift":3600}, {"timeout":10000,"disableResponse":false,"disableRecovery":false,"disableDefaultResponse":true,"direction":1,"srcEndpoint":1,"reservedBits":0,"transactionSequenceNumber":140,"writeUndiv":false}) failed (Data request failed with error: 'MAC_NO_ACK' (0xe9)))
zh:controller:device: Read response to 0xa4c13809c8f5ffff failed (ZCL command 0xa4c13809c8f5ffff/1 genTime.readRsp({"time":823812770,"timeZone":3600,"localTime

[andrei-lazarov]

Device didn't respond to OTA request

This is expected on battery-powered devices.
They sleep to save battery and won't respond to any Z2M messages.
Try to wake it up by pressing some buttons, or use the 'schedule update' button. That will wait until the device wants to update

[nezteew]

Tried button press a lot as described.
Trying now the schedule update. But the temp was already reported 4 times without any update. I will see if it worked tomorrow morning

[nezteew]

No, nothing happens

[yu-tendo]

I had the same issue. It worked after moving 1) moving closer to the coordinator, 2) press the button for ~1 second, 3) start the OTA update. If this does not work, I propose to remove the batteries for a moment and re-try. I just updated my device recently to the latest available firmware (Stack: 1.0 build 4).

[nezteew]

After about 1000000 tries, I have managed the update now, thanks.

[iChris3D]

I'm also interested in the 'Remote Sensor' feature. Support for the feature is mentioned in the official user manual, listed as Remote Temp. & Humi. Display.

SONOFF SNZB-02DR2 AirGuard TH User Manual

Feature Definition on SONOFF Page - Remote Temperature Comparison - In Zigbee mode, links with SNZB-02/02P/02WD/02D/02LD devices to instantly display other sensor temperatures, allowing fast checks without opening your phone or entering the room.

[yu-tendo]

Dear @zmguko
Apologies for the random ping. I believe you handled the initial implementation for this device (SNZB-02DR2) in zigbee-herdsman-converters. If time permits, could you share your thoughts on whether this new functionality is feasible (see previous message), or if you foresee any specific challenges? Thank you!

[lupetril]

Hi, same issue here. I bought 6x SNZB-02DR2 and 1x SNZB-02WD specifically for the Remote Temperature Display feature, but it's not available in either ZHA or Zigbee2MQTT. I've already contacted SONOFF support asking for the specific Zigbee cluster and attribute. I will share their response here once received. Adding my support to the request for @zmguko to look into this.
Thanks!

[lupetril]

Hi, I received a reply from SONOFF support. Sharing it here for everyone's reference:

"After checking with the technician, since there is no external temperature source cluster in the ZB protocol, we can only provide this functionality by designing private attributes. This protocol includes mechanisms for binding and unbinding, as well as maintaining data lists on the gateway and forwarding data when appropriate. This cannot be achieved simply by configuring device bindings in the protocol; therefore, there are no plans to provide this functionality on third-party gateways."

So basically it's a proprietary mechanism managed entirely by the SONOFF gateway, not a standard Zigbee feature.

[nezteew]

Thanks for sharing. Annoying, somehow it must be possible using zb, with the aqara thermometer it is.

[tim-brottsling]

I have the same issue as you, and I also bought this exact setup because of this functionality. It should've occurred to me that it might be proprietary functionality, but it didn't at the time. Shouldn't it be possible to recreate it in HA, if they only gave out the exact specs? In my experience HA can run just about anything if you can code it.

And if they don't give out the specs, shouldn't it be possible to sniff the traffic and reverse engineer it?

[andrei-lazarov]

If it uses Zigbee, it's possible to sniff and reverse engineer

[operekhrest]

The external sensor doesn't work even in the eWeLink app.
The app simply doesn't have the option to add an external sensor, as shown in the advertisements

[tim-brottsling]

I have the same issue as above, but I have been getting it to work with the Sonoff Zigbee Bridge Pro and the eWeLink app. The reason why the bridge was necessary was because my remote sensor (SNZB-02WD) does not support eWeLink directly. That said, I'm not going to use that setup, but was something I did for troubleshooting purposes only. Also note that you should update the device firmware to the latest version, as not all versions support the remote temp functionality.