With firmware 4.2.0 on the NSPanel Pro, the SNZB-02DR2 sensor finally revealed its full capabilities. The configuration page for the device allows selecting an external temperature data source. I select it, confirm it, and press the button on the back of the SNZB-02DR2.
After completing these steps, the display changes, but instead of a temperature reading, I usually see LL.L right next to EXT1. Only after a long time does some (actual?) numerical value appear, but after a while it returns to LL.L—and this keeps repeating. Additionally, when the temperature measured by the external sensor is 0.6 degrees, the display shows .6.
At this point I am stuck, because I do not know whether the behavior described above is caused by the NSPanel Pro, or whether the problem lies in the firmware of the SNZB-02DR2. The former is under eWeLink’s responsibility, the latter depends on Sonoff. The manufacturer mentions SNZB-02DR2 firmware version 1.1.0 or above, but such a version is not available. On top of that, there is also the matter of the eWeLink app, which new version is supposed to be released soon—but it is unclear whether it will fix the observed issues.
Does anyone know how things actually stand now and how they are expected to work in the future?
I just verified with several staffs of SONOFF. They all say the current working firmware version of SNZB-02DR2 is v1.0.2, they don’t know anything about v1.1.0.
The corresponding eWeLink App version is v5.22.0 which has been released on December 10th for Android (Google Play), and the corresponding NSPanel Pro version is v4.2.0 which has been released on December 11th.
We’ll test against SNZB-02DR2 v1.0.2 to find out what goes wrong.
They say they don’t know anything? Then they should visit the product page, which they most likely helped create themselves. Because perhaps they meant to write 1.0.1.
If it’s a mistake, it’s worth fixing or blasting the firmware mention into oblivion as it’s not relevant anymore.
Either way, huge thanks for checking and — most likely — tracking down the error in the description
We’ll test against SNZB-02DR2 v1.0.2 to find out what goes wrong.
Hi, we’ve found out that the LL.L will show up if the actual temperature of external sensor is below zero. Is this the case of your situation? This is clearly a bug of 02DR2, we have reported it to SONOFF staff. They are working on it now.
As for the confusion of v1.1.0 firmware, SONOFF is also doing internal investigation now. Personally, I agree with you that v1.1.0 is a typo for v1.0.1.
Indeed, that makes sense! Yesterday the temperature hovered around zero, and it was one of those days when the outdoor sensor reported borderline values. That would explain the behavior of the SNZB‑02D‑R2, which sometimes showed numbers and sometimes LL.L. Almost as if the firmware developers hadn’t anticipated that the readings could be negative. In a way, that’s understandable, since such values don’t occur indoors - not even in an Eskimo igloo.
Anyway, the important thing is that we finally figured it out. Thanks for looking into it
It seems Sonoff will indeed have to release new firmware after all, and it wouldn’t be surprising if it ends up being version 1.1.0
The entire screen also seems poorly designed to me.
I’d like to display the outside temperature instead of humidity. The digits would be much larger than they currently are. And the humidity would be displayed where the outside temperature is currently.
Maybe it’s just me, but I think many people would prefer the large, readable information about both temperatures as more important than the humidity in the room in a large format.
@MichaelLearnsToCode Would you be so kind as to ask your colleagues at Sonoff whether such a screen reorganization would be possible?
If Sonoff puts some effort into it, it shouldn’t be too scary.
I contacted them and in response I received a request to record a video that was supposedly meant to help identify the problem. It seems they don’t read with understanding.
I won’t be sending a video, because I have neither the time nor the inclination for such actions, and the written description explains everything in detail. Besides, @MichaelLearnsToCode was kind enough to contact Sonoff and wrote about what they intend to do regarding the issue. If they actually follow through, the matter will be closed.
Reorganization won’t be possible because labels like MAX, MIN, EXT1, and EXT2 are permanently printed on the LCD and can’t be changed in software. The only thing they might be able to do is allow the device to display the external sensor reading instead of the internal one. In that case, the values would appear in the large digit area. If they tweak the firmware logic a bit, it could look quite decent on the screen. The internal sensor readings could then be shown in the middle section—smaller, yes, but still the closest match to what you’d expect. I assume that the EXT1 and EXT2 indicators can be disabled, because there’s really nothing more that can be done with them.
It seems the designers at Sonoff didn’t exactly break a sweat when coming up with the concept for the SNZB‑02D‑R2. They could have played it a lot smarter. They went with an LCD simply because it’s cheap and runs happily on a battery. The refresh and reporting intervals are adjustable, and the default timing clearly aims for energy savings - fair enough. But if they had used an e‑paper (e‑ink) display, the possibilities would’ve been far greater while keeping the same design goals. Of course, the price of the device would have shot up a few times over. Still, I’m pretty sure there’d be plenty of people willing to pay extra for a SNZB‑02D‑deluxe edition of this thing. Including me
SONOFF will release v1.0.3 before next weekend to fix the issue of negative temperature display.
Would you be so kind as to ask your colleagues at Sonoff whether such a screen reorganization would be possible?
I’ve conveyed this feature request to SONOFF’s product manager of TH (temperature and humidity) series. She is studying it now. She said she’ll give a reply on this topic herself later.
And on a side note: it’s a bit of a shame the Sonoff team isn’t quite as flexible as the folks over at eWeLink. Life would be so much easier if they were.
I’d be happy with this arrangement… Indoor temperature and three humidity settings, meaning the current one where “ext” and max/min normally are. And outdoor temperature in the humidity position, even without the C/F sign, even if the % sign couldn’t be removed.
And if I understand correctly looking at the pictures, this EXT1 inscription can disappear and turn into MAX, so if that’s the case, you can turn it off completely or give it HUMI
This way we would have large fonts for temperatures and full three-point humidity.
You can’t remove or replace it, of course, but you can probably disable it. The real troublemaker is that string of digits with a decimal place and a minus sign. Sure, you can round the temperature, but you can’t magically add a minus sign where the display simply doesn’t support one - RH never goes negative, and the LCD clearly wasn’t designed with Arctic scenarios in mind. On the bright side, we can safely assume indoor temperatures don’t drop below zero. And even if they did, the missing minus sign on the screen would be the least of your worries at that point
It’s a shame… The display is poorly designed.
I was secretly hoping that maybe they’d somehow improve it, but it’ll probably be the same as always.
Are you talking about the internal temperature and the lack of -? Because I need to display the negative outside temperature for EXT1. I’m ignoring the current bug and waiting for the new firmware, but if it weren’t there, I’d probably consider sending it back.
I bought it solely for displaying both the outside and inside temperature on one screen. If I can’t get the outside temperature readings to be negative, the product becomes useless to me.
No, because this spot was clearly designed to show a “–”. I’m referring to your idea of displaying temperature instead of RH. In this particular field a minus sign simply can’t appear. So if rearranging the screen layout is possible at all, this area could only show the temperature from the built‑in sensor (the indoor temperature).
I get the impression that someone at Sonoff actually had a good idea, but ended up using an off‑the‑shelf display with a fixed layout that couldn’t really be changed. Or maybe the Sonoff design team is working with a slightly limited imagination
I went with an e‑paper display, programmed it (with a fair amount of pain), and now I’ve got exactly what I wanted. It shows a weather forecast with an icon (pulled from a weather service), temperature and RH from a Sonoff sensor outside the window, plus the status of my stream player. Updates are in real time. Of course, it has its limitations — it needs USB power, since the display runs on an ESP32. But I also have a second, smaller one. That one shows temperatures from the Sonoff sensors around the apartment, updates every 30 minutes, and then goes into deep sleep. On a single battery charge it usually runs for about three weeks. Both displays pull their data from an MQTT broker.
There’s a fair bit of tinkering involved when programming in the Arduino IDE. There’s no proper visual GUI editor, so it’s not exactly a walk in the park. But in return you get exactly what you want on the screen. Highly recommended.
We’ve confirmed internally that this model uses a segmented LCD.，The screen layout/icons are fixed in hardware, and the firmware can only turn existing segments on/off—it can’t rearrange the layout. Therefore, your request to “replace humidity with the external temperature and reorganize the display layout” isn’t feasible on the current hardware (and can’t be achieved via an OTA update). We’ll take your feedback on display priority and readability into account for future product improvements. Thank you for the suggestion.
The hardware limitations of a segmented LCD are fully understood. The physical layout, icons and segment positions are fixed in silicon and cannot be modified through firmware or OTA updates. This constraint is clear and not in question.
However, the request does not concern changing the physical layout of the display. It concerns only reassigning which data the firmware places into the existing, predefined segments. Since the device already uses firmware logic to decide what value appears in each field, it remains technically feasible to map different sensor data to those same segments (for example, showing external temperature instead of humidity). Such a change does not alter the LCD structure; it adjusts only the firmware’s data‑to‑segment mapping.
In practical terms, the hardware defines the shape of the display, but the firmware still determines what information is shown within those fixed shapes. If the firmware can already activate specific segments to display numbers or icons, it can also choose which numeric value to present. For this reason, the statement that “nothing can be done” does not fully reflect the actual technical possibilities.
Several ideas proposed in the discussion fall entirely within the capabilities of the existing hardware and could noticeably improve readability and usefulness. If necessary, consultation with the eWelink team (@MichaelLearnsToCode) may help clarify implementation options. In many cases, limitations arise not from technical constraints but from organizational or marketing decisions regarding product consistency. Even so, small firmware adjustments could provide meaningful improvements for users.
At least minimal consideration of such changes would be appreciated.
