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[BK7231N CB3S] Temperature and Humidity Sensor, TH01, PCB:ZY-TH02-CB3S, SHT3X

lktrdng 1578 21
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  • #1 21451730
    lktrdng
    Level 4  
    Again ordered Temperature and Humidity sensor from Aliexpress. Actually two of them.
    I got one of this in ali. It is a device based on CB3S with a CHT8310? sensor and a Tuya chip.
    Model: TH01
    FCC ID: 2A8TU-TH01
    PCB: ZY-TH02-CB3S_V1.0 (2024-12-03)
    Disassembled temperature and humidity sensor with visible electronic board and casing.

    Case holes detail:
    White rectangular sensor with labeled holes for LED, int button, and possible HT sensor.

    PCB detail:
    Printed circuit board with electronic components.

    HT Chip:
    Close-up of a chip labeled SML DPAT. Close-up of a microchip on a PCB.

    How it ended:
    Printed circuit board with connected wires.

    I wasn't able to put OBK on it using bk7231flasher_1.3.3. No reboot or CEN allowed me. So, I needed to desolder something.
    For first device I tried desoldering the CB3S chip and my (lack of) soldering skills resulted in a lot of pads broken :P. But the CB3S survived and I was able to program OBK on it.
    For second device I tried desoldering the Tuya chip, this time pads survived but still wasn't able to program it, therefore I needed to desolder the CB3S, this time all the pads survived.
    Long story short, after several tries I decided to remove the Tuya chip and connect the CB3S directly to the supposed CHT8310. I assumed the PCB included a CHT8310 based on the picture of it and the fact the PCB literally has CHT8310 printed on it in some test points, specifically CHT8310_SDA, CHT8310_SCL and CHT8310_VDD.
    To leverage the configuration I made to some other device I wired the CHT8310 chip to P9 and P6 of CB3S as per the pinout Here

    When loading the driver I always get temp=125 hum=0, which means for me there is an issue with the communications.
    Therefore I loaded the I2C driver and when I ran scanI2C soft I got
    Code: text Expand Select all Copy to clipboard
     Info:I2C:Address 0x44 (dec 68)

    That is, as per my understanding the address of a SHT30 chip.
    When trying to load that driver I realized it is not included in the current standard release of OBK, where can I get a version including SHT30 to see if that driver is capable of handling the chip?.
    Attachments:
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  • #3 21452607
    max4elektroda
    Level 20  
    I knew deep in my box with sensors there was an SHT31 ;-)

    Looks like it should work:


    Screenshot of OpenBK7231N interface showing temperature and humidity data.
  • #5 21452702
    max4elektroda
    Level 20  
    Yes, a clear picture of the sensor would be great.

    While 0x44 is the default address for SHT3x, it's also possible on CHT8310:

    See e.g. https://github.com/RobTillaart/CHT8310 :

    The CHT8310 supports up to 4 devices on the I2C bus.
    AD0 Address Notes
    GND 0x40 CHT8310_DEFAULT_ADDRESS
    VCC 0x44
    SDA 0x48
    SCL 0x4C
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  • #6 21452715
    divadiow
    Level 34  
    yes and Info:I2C:Address 0x44 (dec 68) was the detection for my CHT8320
  • #7 21454382
    lktrdng
    Level 4  
    >>21452650 I uploaded new images for the chip the best I could and I can confirm, only 4 legs.

    Added after 1 [hours] 14 [minutes]:

    >>21451932 Tried your firmware and got

    User interface showing temperature and humidity data with configuration options.
  • #8 21454680
    max4elektroda
    Level 20  
    So it seems it actually is an SHT3x sensor or a clone. Good to know, maybe @divadiow this will solve your non functional device, too?

    Added after 10 [minutes]:

    At least your sensor seems very much the same device like the image above
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  • #9 21454700
    divadiow
    Level 34  
    But that's mad! Sensylink said it was a CHT8320...
  • #10 21454729
    max4elektroda
    Level 20  
    Yes, they should know.
    Maybe the protocol is kind of equal so it will give values if requested by the SHT protocol? The values at least look kind of sensible
  • #11 21454746
    divadiow
    Level 34  
    weird. i must get to the bottom of this!
    User interface of the OpenBK7231N system displaying temperature and humidity information.

    pins are correct. I get expected address with soft scan

    Added after 27 [minutes]:

    max4elektroda wrote:
    So it seems it actually is an SHT3x sensor or a clone.

    also weird. Sensirion SHT3x has 8 legs I thought and the logo in the pic is of Sensylink
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  • #12 21454976
    max4elektroda
    Level 20  
    divadiow wrote:
    weird.

    I couldn't find a better word for this.
  • #13 21455006
    lktrdng
    Level 4  
    I moved my LED connection to P8 to free the ADC3 pin, any advice on how to measure the battery voltage?
  • #14 21456145
    max4elektroda
    Level 20  
    lktrdng wrote:
    any advice on how to measure the battery voltage

    Maybe take a look here

    https://www.elektroda.com/rtvforum/topic3959103.html

    it's about the "battery driver" which should do some kind of measuring on the ADC pin.
    Only took a brief look, you will need a voltage divider if I got it right, but it seems to be doable to build a divider like shown here

    https://www.elektroda.com/rtvforum/topic3959103.html#20588380
  • #16 21572955
    rethink621
    Level 3  
    Hello, I have a few of these. Trying to to identify them is difficult when they're all called TH01 and then the PCBs are marked with all sorts of things. It is the same as the pictures in the first post. I have flashed OpenBeken 1.18.109 but I'm trying to get the configuration part correct. I'm looking at the OpenBeken web app config page, but cannot find the exact device in the drop-down list. Really I don't know what to do - I'm fairly new to this, but can see the device in HA. Many thanks for any help.
  • #18 21580179
    p.kaczmarek2
    Moderator Smart Home  
    The device in the first post is a TuyaMCU battery powered device. It's a bit hard to convert, but it's supported by OBK, just as you linked.

    There are also battery powered devices without TuyaMCU - they can use deep sleep mechanism. They are a bit more flexible. TuyaMCU battery powered can be converted to "deep sleep" battery powered device with some PCB changes, removal of MCU, etc. This can also work as long as the onboard sensor is supported by OBK itself.
    Helpful post? Buy me a coffee.
  • #19 21583547
    rethink621
    Level 3  
    I've managed to get mine going using BK7231GUIFlashTool-v19.

    1. Desolder CB3S from PCB (or cut RX/TX temporarily as noted and bridge Batt - (0V) to pin 9 GND)
    2. I used one of these flash boards for ESP-12x to flash the CB3S
    [BK7231N CB3S] Temperature and Humidity Sensor, TH01, PCB:ZY-TH02-CB3S, SHT3X
    3. Use a BK7231GUIFlashTool to flash current OpenBeken firmware.
    4. I also used Restore RF Part
    5. Resolder the CB3S onto PCB and bridge Batt- to pin 9 GND, so the MCU is on continuously.
    5. Connect to the AP that it creates.
    6. Configure MQTT, WiFi and reboot
    7. Find the IP address when it connects to your WiFi.
    8. Launch the Web Application and create a new autoexec.bat
    9. Paste in:
    Code: text Expand Select all Copy to clipboard
    startDriver TuyaMCU
startDriver tmSensor
// dpID 27 is temperature div 10
setChannelType 27 temperature_div10
linkTuyaMCUOutputToChannel 27 val 27
// dpID 46 is % humidity
setChannelType 46 Humidity
linkTuyaMCUOutputToChannel 46 val 46
// dpID 101 is battery state - low(0), mid(1) and high(2)
setChannelType 10 ReadOnly
linkTuyaMCUOutputToChannel 101 enum 10
setChannelLabel 10 Battery 


    10. Go to Home Assistant Config and press Start Home Assistant Discovery
    11. HA should find it and see the sensors. It might take a while for values to appear.
    12. Remove the Batt- to pin 9 bridge.

    I've found that my units report about every 40 minutes to HA.
  • #20 21619299
    cobakind
    Level 3  
    @lktrdng Hi! I have exactly the same sensor, but I can't get it to work. I removed the Tuya chip and soldered it exactly like yours. I took the firmware from here, with SHT3x support. But I always have temperature=130 and humidity=100. Can you please tell me how you configured "Pin Settings" and what's in autoexec.bat?
  • #21 21621270
    rethink621
    Level 3  
    The autoexec.bat contains the text in the code box above. There aren't any other settings. Make sure your sensor is exactly the same. Make sure the PCB code is the same (date code may be different) and it looks the same. Post a photo here if you're unsure.
  • #22 21622043
    cobakind
    Level 3  
    >>21621270 Thanks for the quick reply! Yes, I have exactly the same PCB, the date code is the same (photo attached). I don't know if my "Pin Settings" are set up correctly. Can you tell me the correct "Pin Settings" for this PCB?
    [BK7231N CB3S] Temperature and Humidity Sensor, TH01, PCB:ZY-TH02-CB3S, SHT3X
    [BK7231N CB3S] Temperature and Humidity Sensor, TH01, PCB:ZY-TH02-CB3S, SHT3X
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Topic summary

The discussion centers on identifying and flashing firmware for a temperature and humidity sensor device labeled TH01, based on the BK7231N CB3S chip with a Tuya MCU and a sensor initially thought to be CHT8310 but more likely an SHT3x or its clone. The sensor PCB is marked ZY-TH02-CB3S_V1.0. Visual inspection and I2C address scans suggest the sensor has only 4 legs, inconsistent with the CHT8310 or CHT8320 which have more pins, and the sensor appears to be a Sensirion SHT3x or a clone, despite some confusion due to logos and pin counts. Firmware attempts using bk7231flasher failed without desoldering the CB3S chip; successful flashing was achieved using BK7231GUIFlashTool with OpenBeken firmware. Configuration involves enabling TuyaMCU and tmSensor drivers, mapping Tuya data points for temperature, humidity, and battery state, and setting up MQTT and WiFi. The device is battery powered with a TuyaMCU, which complicates conversion but is supported by OpenBeken. Some users discuss measuring battery voltage via ADC pins using voltage dividers. The thread references external resources for firmware, drivers, and configuration examples, highlighting the challenges of sensor identification and firmware flashing on these Tuya-based BK7231N devices.
Summary generated by the language model.
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