Tiny desktop thermometer/hygrometer with display - SNZB-02D - interior and pairing

The microcontroller is an EFR32MG22, external flash memory probably for OTA image storage.

Indeed, I now recall seeing the same thing in the Zigbee button too Sonoff SNZB-01P .

I own something similar:
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I think I need to throw it in here.
It's been working great for two years now. It works on AAA rechargeable batteries and on batteries.
Last week I replaced the rechargeable batteries for the first time after two years.

A very similar product, I in turn plan to look for something that would still display the current date and time.

What did you pair it with @VPSA132 , Home Assistant, or Tuya gateway, or something else?

He works with the Tuya gate from LIDLA.

p.kaczmarek2 wrote:

Do you use this type of product, or perhaps know of a better alternative to the SNZB-02D?

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Xioami Mi2. price about 25zł
Factory sends telegrams over Bleutooth including temperature, humidity, battery status and more
All you need is some device on esp32 with tasmot32-bluetooth and send data after mqtt to broker
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Here the software has been changed to ATC
The data is sent via Rule in the tasmot.

Example rule with sending data to Domoticz

ON ATCe5d91c#temperature DO Var1 %value% ENDON ON ATCe5d91c#humidity DO Var2 %value% ENDON ON ATCe5d91c#battery DO publish domoticz/in {"idx":176, "svalue":"%Var1%;%Var2%;1", "Battery":%value%} ENDON

In addition, the tasmota sends all data to the tele/name/sensor topicle
tele/Mi_Termo/SENSOR = {"Time":"2025-01-15T14:30:40","ATCca8ed0":{"mac":"a4c138ca8ed0","Temperature":20.1,"Humidity":30.3,"DewPoint":2.1,"Btn":0,"Battery":94,"RSSI":-82},"TempUnit":"C"}

A Xiaomi Mi3 has recently appeared which works similarly and has in addition time, date

I have something similar in quantity of 5 units from Xaiomi:
Xiaomi Mijia Thermometer 2 Bluetooth - works for a couple of years, CR2032 battery, battery lasts about a year, but I plan to build a BT gateway to download data (I saw a description somewhere), power issue, but I guess data transfer can be supplemented with battery status.

sq3evp wrote:

but I guess the data transfer can be supplemented with the battery status.

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What I have specified includes the battery status

And here's how else to change the software and integrate with HA
https://community.home-assistant.io/t/xiaomi-...egration-pvvx-custom-firmware-may-2023/572569

I have 11 pieces

Very interesting solution @SławekSS , I will have to test.

SławekSS wrote:

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Just some device on esp32 with tasmot32-bluetooth and send the data over mqtt to the broker

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And then one device from the ESP32 is in the role of "hub" and supports several or more such sensors?

Yes, I don't know how many max, but I have two esp32(ground floor and ground floor) and both support me these 11 thermometers. In each esp I have 11 rules entered for each thermometer because I don't know which esp will just receive the bluetooth data.
One esp can probably handle up to 10 thermometers(9 for sure)
Here is a snapshot of what the Sonoff POWR316 is catching with esp32. In addition to what it is supposed to do, it also handles thermometers

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p.kaczmarek2 wrote:

... I, in turn, plan to look for something that would still display the current date and time.

Maybe something like this? :

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@VPSA132 I'll order and report back once I've tested it, which is probably in two-three months, given the queue of devices I have (including a Tuya three-phase meter what I was flashing for a reader)

SławekSS wrote:

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Here's a snapshot of what the Sonoff POWR316 with esp32 is catching. In addition to what it is supposed to do, it also handles thermometers

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POWR316 , I tested it. Lots of those sensors, how about range?
If you'd like, consider describing your setup and presenting it in the 0bbfbc094 Smart Home Tutorials[/url] . See also here .

p.kaczmarek2 wrote:

how about the range?

ok, quite considerable for BT.
I have one BT downstairs in the garage and the other upstairs on the opposite side.
Each one catches the signal from 9 thermometers(I think that's the max the tasmot can process) spread around the house(11 units). My house is quite large.
One catches thermometers with rssi from -89 to -75dBm and the other from -56 to -88dBm. Along the way several walls, ceiling etc.

p.kaczmarek2 wrote:

(including a Tuya three phase meter

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I use ORNO OR WE-517 I read with python script over rs-485 to mqtt

It's nice that a topic about ZigBee and not just WiFi has come up. I decided to use thermometers on ZigBee to control the floor actuators. I bought different ones to do tests on what works best in a domestic environment. Here is my set up:
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Here we have an AQARA sensor, an RTX (identified as TS0201) and a sensor with a display (TY0201). As the sensor is to work as a thermostat with a relatively small temperature range (15-28 deg) the absolute temperature value is not important to me. Differences in the range of 0.3-0.4 deg are negligible, as what will really matter is the placement of the sensor itself (e.g. height above the floor). So what is important? I have found that stability of operation, speed of reporting and of course range are key.

The range test I conducted is not entirely conclusive, but some conclusions can be drawn. The AQARA performed best, similar (slightly worse) results were obtained by the other sensors, with the one with the display being the worst at the range test.
In terms of reporting resolutions, the one with the display reports values with a resolution of 0.1st, the others 0.01st.

The key is the speed of reporting - i.e. how long after a temperature change you get new readings. My condition was that the value should not exceed 0.2st. This is important with underfloor heating - it has a lot of inertia and even when the heating is turned off the temperature will continue to rise. The thermometer with the display usually reported 0.1st at each change (i.e. with its resolution). Occasionally, however, it was 0.2 degrees - probably when the temperature was rising faster. However, it was never more than that. RTX reported every 0.13st or so. AQARA also reported well, but there were times when the spikes were unacceptable to me (0.4st). AQARA measures temperature, humidity and pressure. Changing any of the parameters causes reporting. However, I have the impression that if the humidity and pressure do not change the temperature reporting is at 0.4st. It should be noted that the reporting is not extremely frequent even with large temperature changes. Usually this period is about 5minutes. In the absence of significant changes it can be 30 minutes or more.

Another test - how do the sensors cope with loss of connectivity? I took the sensors away for 2 days and then they were returned to their place. The thermometer with display was already giving new data after 25 minutes. RTX after about 4 hours (although in other tests it was much shorter). AQARA after ... 32 hours! Overall when it comes to the very highly regarded AQARA, there is some drama.

Despite the battery power, all the sensors were able to switch to a better/other router.

The RTX thermometer has been running for over a year (I bought it for my first ZigBee tests) and reports 100% battery. The AQARA, which has been running for a few months reports 63%.

At the moment my favourite is the RTX. However, I would love to read your comments on ZigBee thermometers.

https://a.aliexpress.com/_EIdclK0
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I bought one and it works with Home Assistant ZHA

krzbor wrote:

Another test - how do the sensors handle loss of connectivity?

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Quite long, these Xiaomi ones are a dozen seconds to a minute max

@krzbor Aqara I once tested and I recall that there was a trick there that if you pressed the button, it reported more often, so some people forcefully shorted the button, you know it maybe?
And I know, I tested it with a motion sensor: Aqara motion sensor RTCGQ11LM - interior, modification of refresh time I don't know if this also makes sense with thermometers

SławekSS wrote:

Quite a long time, these Xiaomi ones are several seconds to a minute max

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As I wrote - regardless of the circumstances, the sensors do not connect more often than every 5 minutes. So these seconds are rather unrealistic - well, unless you hit another transmission time.

Added after 12 [minutes]:

p.kaczmarek2 wrote:

Aqara I used to test and I recall there was a trick where if you pressed the button it reported more often, so some people forcefully shorted the button, you know it maybe?

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I've read about this somewhere, but there is already a clear drop in voltage. I do expect those 2 years of battery life from a ZigBee device though.

krzbor wrote:

do not make a call more often than every 5 minutes

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This is not about making a call just sending a telegram without waiting for a reply.
The telegram is sent probably every 15s along with a refresh of the display, of course I could be wrong, but after switching on the esp32 within a minute the data from the sensors that are in range appear

SławekSS wrote:

The telegram is sent I think every 15s along with a refresh of the display, of course I could be wrong, but when esp32 is switched on there is data from sensors that are in range within a minute

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I think you're writing about Bluetooth, not ZigBee

Well yes, I was comparing to Xiaomi

SławekSS wrote:

these Xiaomi are several seconds to a minute max

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And the Xiaomi's go on BT

SławekSS wrote:

And Xiaomi go on BT

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Yes, that's what I was describing - similar functions, but BT not ZigBee.

With zigbee, you can configure how the measured values are reported. Two types of report triggering are possible: periodic (you can set what time interval you want a new value to be sent - from 250ms to hours) and per value change (you set the delta of the value). You can also configure a combination of these methods. Only this configuration has to be done when the device is online (during or shortly after onboarding, or when it sends a report) - this of course applies to sleepy devices (mostly any battery-powered). For example, a device that is on all the time (with routing capability) is the Vindstyrka air sensor from IKEA.

And have you had the opportunity to compare humidity readings with other units? Or have colleagues with several pieces put them side by side and checked what the scatter of readings is?

I checked. Xiaomi Mi2
11 side by side as close together as possible, so that they do not touch each other and at the same time you can read the result on the display.
After more than 2 hours of lying like this
Temperature difference +- 0.2stC
Difference in humidity +- 1%.

I would like to mention that after uploading alternative software it is possible to calibrate/correct the above indications.


I also have a similar Hama thermometer, much larger without communication and here there was already a difference. temperature about 0.5stC and humidity a good few % but less than 8%.

I did not check after reading via BT.

SławekSS wrote:

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After more than 2 hours of lying like this
Temperature difference +- 0.2stC
Difference in humidity +- 1%.

I tested 5 pieces and similar impressions - they are quite accurate considering the price.

SławekSS wrote:

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I would like to mention that after uploading alternative software it is possible to calibrate/correct the above mentioned indications.

Any links and descriptions?
I don't know what the inside looks like and if it is difficult to upload the soft.

Post #9 link to ha integration there is a description of how to flash via BT.

All you need is a smartphone with BT
Chrome browser, and a link to the program.

Edit:
I forgot to add that via OTA is only possible with firmware version 1.0xxxxxxxx.
If there is a version 2.xxxxxxxx then only via UART.

jarekgol wrote:

Have you had occasion to compare the humidity readings with other units? Or have colleagues who have several pieces put them side by side and checked what the scatter of readings is?

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I'm working on a similar comparison for different measured quantities, but I'm operating on sensors alone, I have DS18B20, DHT11, BMP280 and AHT20 hooked up, on four boards at the moment, so there will be at least 4*4 = 16 sensors:
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Results of the comparison soon on the forum.

A year ago, I hooked up 5xDHT22 and 10xDS18B20 to an arduino and attached a recording from a car of readings every, it seems, 2 or 5 min.