[BK7231N] [CB3S] [AHT20] TH01 Generic Temperature and Humidity Sensor Teardown

anthonythomas 51039 180

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How do I finish the OpenBK autoexec setup for a TH01 temperature and humidity sensor with TuyaMCU?

Add the TuyaMCU-to-channel mappings, not just the two drivers: `startDriver TuyaMCU; startDriver tmSensor; setChannelType 1 temperature_div10; linkTuyaMCUOutputToChannel 1 val 1; setChannelType 2 Humidity; linkTuyaMCUOutputToChannel 2 val 2; setChannelType 3 ReadOnlyLowMidHigh; linkTuyaMCUOutputToChannel 3 enum 3; setChannelLabel 3 Battery` [#20516557][#20516646][#20845707] dpID 1 is temperature in tenths of a degree, dpID 2 is humidity, and dpID 3 is the battery state (low/mid/high) [#20516557][#20516646] For battery-powered operation, the Wi‑Fi module is controlled by the MCU, so initial setup often needs external 3.3 V to the Wi‑Fi module; for no-MQTT use, OBK can either use `tuyaMcu_defWiFiState 0x04` or an empty MQTT host field in newer builds [#20642216][#20931402]

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#31 20628188 23 Jun 2023 12:54

grericht grericht

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Post #31
20628188 23 Jun 2023 12:54

I read these articles. I did not have two left hands, but I did not study electric-technic. So I have big problems to understand all of what is written, and I don't know what is really useful if I can't understand everything. I just want it to work.

I now have:
1. Cut the RX and TX traces at the Tuya MCU.
2. Flashed actual BK7231N bin with Windows flasher (had many problems but got it flashed on 2 different devices).
3. Resoldered the cut RX and TX traces at the Tuya MCU.
Did not work: Powered the device (TH01 from this thread). First, I tried to power it with the battery pins, but the access point WLAN goes on and off all the time, so I can't get a stable connection to the access point - I think the reason is the battery saver or Tuya MCU?
4. Then I powered the CB3S platine with 3.3V, and I got a stable connection.
5. I did standard Wi-Fi settings and MQTT and restarted. TH01 is now in my home network. Sometimes it restarts. Is this normal?
6. I copied this line "backlog startDriver tuyaMCU; startDriver tmSensor; linkTuyaMCUOutputToChannel 1 val 1; setChannelType 1 temperature_div10; linkTuyaMCUOutputToChannel 2 val 2; setChannelType 2 Humidity;linkTuyaMCUOutputToChannel 3 val 3; setChannelType 3 ReadOnly;" in the start command.
7. Restarted.
Trying to power it with the battery will not work. Where should I connect the + and -?
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#32 20628348 23 Jun 2023 15:00

DeDaMrAz DeDaMrAz

Level 22

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Post #32
20628348 23 Jun 2023 15:00

grericht wrote:

Ok. Will try this next.

I now have reached 2 different Tuya thermo/hygrometers with Open Beken flashed.
1 I have resoldered the cut traces and on the other I didn't up to now.
When I power the devices there is the Open Beken net, but on both I only get a short connection and can't reach 192.168.4.1. Connection will be lost very shortly.
Is this because of the energy-saving mode of these devices?
Did I have to resolder both?
How can I get the configuration on the devices?

@p.kaczmarek2 this looks to me like the light module, it needs a configuration otherwise the tuyaMCU will shut down - no heartbeat maybe?

My solution for this was to power on the device (WiFi module) externally, configure everything then power it on batteries.

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#33 20629135 24 Jun 2023 11:21

grericht grericht

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Post #33
20629135 24 Jun 2023 11:21

after configuring wlan settings i have some problems with configuration.
i powered directly the cb3s platine

first time i try to search in web app (config/Pick a device from the dropdown) for the correct device an found "Tuya TuyaMCU TH01 ...". -> copy device settings ->
nothing changed but command: "backlog startDriver tuyaMCU; startDriver tmSensor; linkTuyaMCUOutputToChannel 1 val 1; setChannelType 1 temperature_div10; linkTuyaMCUOutputToChannel 2 val 2; setChannelType 2 Humidity;linkTuyaMCUOutputToChannel 3 val 3; setChannelType 3 ReadOnly;" ->
save pins
power off/on -> no change?! why?!

when i use the "normal" interface option "config"/change startup command text it seems to be to long. i can copy and paste. all is pasted.
after saving it is cuted and filed:
original: backlog startDriver tuyaMCU; startDriver tmSensor; linkTuyaMCUOutputToChannel 1 val 1; setChannelType 1 temperature_div10; linkTuyaMCUOutputToChannel 2 val 2; setChannelType 2 Humidity;linkTuyaMCUOutputToChannel 3 val 3; setChannelType 3 ReadOnly;
after saving: backlog startDriver tuyaMCU; startDriver tmSensor; linkTuyaMCUOutputToChannel 1 val 1; setChannelType 1 temperature_div10; linkTuyaMCUOutputToChannel 2 val 2; setChannelType 2 Humidity;linkTuyaMCUOutputToCha<input type='hidden' name='startup_cmd' value='1'><br><input type=
after rebooting i get an error in web app/config/curret device: Error: SyntaxError: JSON.parse: expected ',' or '}' after property value in object at line 1 column 535 of the JSON data

i have to return to factory settings by web app
what is the correct way to get the startup command working
#34 20639691 02 Jul 2023 23:58

maxen0815 maxen0815

Level 3

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Post #34
20639691 02 Jul 2023 23:58

Hi, I'm struggling with the same device...
After flashing and getting the config done, I don't get any useful data on any channel... all are set to 0

Any idea where this effect is coming from?
#35 20639749 03 Jul 2023 06:07

p.kaczmarek2 p.kaczmarek2

Moderator Smart Home

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Post #35
20639749 03 Jul 2023 06:07

Hello, it seems that no drivers are running. What is your current GPIO configuration on the panel?

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

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#36 20639863 03 Jul 2023 09:04

maxen0815 maxen0815

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Post #36
20639863 03 Jul 2023 09:04

To be honest, I did not change the GPIO configuration since I expected the RX/TX communication with the MCU to be working "out of the box" %-)

Is there a reference pinout I missed while reading the tutorials in the forum?!

I referred to this post: https://www.elektroda.com/rtvforum/topic3947585-30.html#20427369 asking for the pin-setting as well and got the response "Just to get the temperature and humidity, the pin setting is not directly necessary."
#37 20640085 03 Jul 2023 12:08

p.kaczmarek2 p.kaczmarek2

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Post #37
20640085 03 Jul 2023 12:08

If your device is TuyaMCU one, then maybe you need to copy the config from this post?
https://www.elektroda.com/rtvforum/topic3947585-30.html#20383876

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

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#38 20640830 03 Jul 2023 21:45

maxen0815 maxen0815

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Post #38
20640830 03 Jul 2023 21:45

With the mentioned Autoexec, it seems to load some drivers, but still no values visible...
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#39 20642216 04 Jul 2023 22:14

p.kaczmarek2 p.kaczmarek2

Moderator Smart Home

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Post #39
20642216 04 Jul 2023 22:14

It is possible that you are approaching it in an incorrect way.

It seems that you have a TuyaMCU device, a battery-powered one.

Those devices are always controlled by the MCU. MCU only powers on the WiFi module when it wants to report data, WiFi module then initiates the UART conversation and MCU sends data to WiFi module. WiFi module then reports data to cloud and sends an "I'm finished" packet to MCU, which then turns off the WiFi module again.

All that is done in order to preserve the batteries.

If you are powering the WiFi module externally, then you won't get measurement results.

So I will say this, the approach here is as follows:
1. Get dpIDs data (or find existing matching config).
2. Flash OBK.
3. Power externally WiFi module.
4. Setup OBK autoexec with dpIDs and channel types.
5. Pair with Ha, do Home Assistant discovery.
6. Disconnect external power for WiFi module.
7. Put in batteries.
8. Then it should start waking up for itself, for 30 seconds or so, every now and then and report data to your HA.

Here is my topic about such a sensor:
https://www.elektroda.com/rtvforum/topic3975583.html

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

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#40 20684096 07 Aug 2023 01:39

auntlydia auntlydia

Level 10

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Post #40
20684096 07 Aug 2023 01:39

Hello everyone,

thank you for this post, which was able to give me the basic information I needed in order to setup this sensor (TH01). With the aforementioned discussion about whether or not to sever some pins or desolder the WiFi module, I want to add some comments.
I desoldered it for the reason that I was not able to get the device's created WiFi AP up and running long enough to enter configuration - simply because I was not patient enough. It is not necessary, don't do it, you don't need to. It was taking ages to desolder the battery pins, which was necessary in order not to melt the housing for the later-on desoldering of WiFi module with hot air, it's not worth it, I even damaged the housing while desoldering the battery terminals with my iron - a pain. Now, I would like to quickly give you the steps that worked for me.

I flashed 4 sensors of the same type, and it worked the same for all of them.

1. have a look at the relevant pins:

2. solder 5 indidivual wires to each of those. For TX / RX pins, you can also use the large round test pads on the motherboard, they are easier to access.

3. connect 4 wires (3.3V, GND, TX, RX) to your USB-UART module, mind the 3.3V setting! make sure to connect TX ---> RX and RX ---> TX! If you want to use external 3.3V power source, connect the ground wire (-) of that source to BOTH our sensor AND USB-UART module.

4. prepare Windows tool bk7231flasher: download current firmware (7231N!), I also recommend setting "Change OBK settings for flash write", this way you can already enter your WiFi credentials and mqtt data. Also, here you can already set the flags (I only used flag 10) and enter the startup code that is required for this module

[backlog startDriver tuyaMCU; startDriver tmSensor; linkTuyaMCUOutputToChannel 1 val 1; setChannelType 1 temperature_div10; linkTuyaMCUOutputToChannel 2 val 2; setChannelType 2 Humidity;linkTuyaMCUOutputToChannel 3 val 3; setChannelType 3 ReadOnly;]

so all that's left to do after flashing is to double check all the name settings and start Home Assistant discovery via the web interface.
(--> If the startup command doesn't work later on, you need to enter it again via web interface. If there is no button to submit, it might be necessary to clear OBK config via web app command, after that you can re-enter new startup command)

5. Now connect USB (and then external power if you use it) and wait a moment for it to show up in UART port. Also, give the module few seconds to power on. Don't forget to select "Automatically configure OBK on flash write" if you chose this setting in step 4

6. Now make sure correct firmware is selected and then start process "Do backup and flash new", confirm dialogue and wait for log window to show waiting status. Now shortly (!) connect the end of CEN-wire to one of your GND terminals (just touch it and immediately release again), it will reset the device and reading/writing should start without any error messages. If you get any crucial error message, make sure to repeat step 5 and wait a minute before you start read/flash process. It worked for all my 4 sensors without exception.

7. After successful flash, disconnect the module first. Then the important part in order to make the WiFi-connection work: connect only 3.3V and GND (doesn't matter where from) to the wires that are still attached, to power the device on again. Now, wait patiently! WiFi will pop up few times, after few minutes it will be stable! Either way, as AP if not preconfigured, or already in your router with new IP address. Then open web interface, finish configuration (HA discovery, names, startup command etc), and before you desolder the wires, pop in batteries and test if it still works. After disconnecting wires it will be annoying to acces the web interface - yet it is possible by either keeping the module's button pressed or press it down continuosly in 2 second intervals or so.

Result in HA:

(it was raining a lot here today, we can see it 😅 )

Good luck!
#41 20716440 31 Aug 2023 17:42

dgel27 dgel27

Level 8

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Post #41
20716440 31 Aug 2023 17:42

Hi, I also have same device, and load OpenBeken FW (Thanks for it!).
Now, MCU's cycle power on is too short to collect and send data:

Spoiler:

Info:MAIN:Main_Init_Before_Delay
Info:CFG:####### Boot Count 178 #######
Warn:CFG:CFG_InitAndLoad: Correct config has been loaded with 7 changes count.
Error:CMD:no file early.bat err -2
Info:GEN:PIN_SetupPins pins have been set up.
Info:MAIN:Main_Init_Before_Delay done
Info:MAIN:Main_Init_Delay
Info:MAIN:Main_Init_Delay done
Info:MAIN:Main_Init_After_Delay
Info:MAIN:Using SSID [************]
Info:MAIN:Using Pass [***********]
Info:MQTT:MQTT_RegisterCallback called for bT obk_C4CC000F4/ subT obk_C4CC000F4/+/set
Info:MQTT:MQTT_RegisterCallback called for bT bekens/ subT bekens/+/set
Info:MQTT:MQTT_RegisterCallback called for bT cmnd/obk_C4CC000F4/ subT cmnd/obk_C4CC000F4/+
Info:MQTT:MQTT_RegisterCallback called for bT cmnd/bekens/ subT cmnd/bekens/+
Info:MQTT:MQTT_RegisterCallback called for bT obk_C4CC000F4/ subT obk_C4CC000F4/+/get
Info:CMD:CMD_StartScript: started autoexec.bat at the beginning
Info:MAIN:Main_Init_After_Delay done
Info:MAIN:Started tuyaMCU.
Info:MAIN:Started tmSensor.
Info:GEN:Channel 1 type changed to temperature_div10
Info:GEN:Channel 2 type changed to Humidity
Info:GEN:Channel 3 type changed to ReadOnly
Info:MAIN:Time 1, idle 276116/s, free 77120, MQTT 0(0), bWifi 0, secondsWithNoPing -1, socks 2/38
Info:MAIN:Time 2, idle 191115/s, free 77120, MQTT 0(0), bWifi 0, secondsWithNoPing -1, socks 2/38
Info:MAIN:Time 3, idle 189013/s, free 77120, MQTT 0(0), bWifi 0, secondsWithNoPing -1, socks 2/38
Info:MAIN:Time 4, idle 190149/s, free 77120, MQTT 0(0), bWifi 0, secondsWithNoPing -1, socks 2/38
Info:TuyaMCU:TUYAMCU received: 55 AA 00 01 00 24 7B 22 70 22 3A 22 6C 66 33 36 79 35 6E 77 62 38 6A 6B 78 77 67 67 22 2C 22 76 22 3A 22 31 2E 30 2E 30 22 7D 99
Info:TuyaMCU:TuyaMCU_ProcessIncoming[ver=0]: processing command 1 (QueryProductInformation) with 43 bytes
Info:TuyaMCU:TuyaMCU_ParseQueryProductInformation: received {"p":"lf36y5nwb8jkxwgg","v":"1.0.0"}
Info:MAIN:Time 5, idle 191246/s, free 77120, MQTT 0(0), bWifi 0, secondsWithNoPing -1, socks 2/38
Info:MAIN:ssid:******** key:********
Info:MAIN:Time 6, idle 175499/s, free 71856, MQTT 0(0), bWifi 0, secondsWithNoPing -1, socks 2/38
Info:MAIN:Boot complete time reached (5 seconds)
Info:CFG:####### Set Boot Complete #######
Info:MAIN:Time 7, idle 184013/s, free 71608, MQTT 0(0), bWifi 0, secondsWithNoPing -1, socks 2/38
Info:MAIN:Time 8, idle 84901/s, free 71592, MQTT 0(0), bWifi 0, secondsWithNoPing -1, socks 2/38
Info:MAIN:Time 9, idle 0/s, free 71592, MQTT 0(0), bWifi 0, secondsWithNoPing -1, socks 2/38
Info:MAIN:Time 10, idle 0/s, free 71592, MQTT 0(0), bWifi 0, secondsWithNoPing -1, socks 2/38
Info:GEN:dhcp=0 ip=0.0.0.0 gate=0.0.0.0 mask=0.0.0.0 mac=50:8b:b9:4f:bc:fc
Info:GEN:sta: 0, softap: 0, b/g/n
Info:MAIN:Main_OnWiFiStatusChange - WIFI_STA_CONNECTING - 1
Info:MAIN:Main_OnWiFiStatusChange - WIFI_STA_CONNECTED - 4
Info:MAIN:Main_OnWiFiStatusChange - WIFI_STA_CONNECTED - 4
Info:MAIN:Time 11, idle 90880/s, free 71952, MQTT 0(0), bWifi 1, secondsWithNoPing -1, socks 2/38
Info:TuyaMCU:TUYAMCU received: 55 AA 00 02 00 00 01
Info:TuyaMCU:TuyaMCU_ProcessIncoming[ver=0]: processing command 2 (MCUconf) with 7 bytes
Info:TuyaMCU:TuyaMCU_ProcessIncoming: TUYA_CMD_MCU_CONF, TODO!
Info:MAIN:Time 12, idle 203976/s, free 71992, MQTT 0(0), bWifi 1, secondsWithNoPing -1, socks 2/38
Info:MQTT:mqtt_userName homeassistant
mqtt_pass
mqtt_clientID obk_C4CC000F4
mqtt_host 192.168.1.22:1883
Info:MAIN:Time 13, idle 190063/s, free 71904, MQTT 0(1), bWifi 1, secondsWithNoPing -1, socks 2/38
Info:MQTT:mqtt_connection_cb: Successfully connected
Info:MQTT:mqtt_subscribed to obk_C4CC000F4/+/set
Info:MQTT:mqtt_subscribed to bekens/+/set
Info:MQTT:mqtt_subscribed to cmnd/obk_C4CC000F4/+
Info:MQTT:mqtt_subscribed to cmnd/bekens/+
Info:MQTT:mqtt_subscribed to obk_C4CC000F4/+/get
Info:MAIN:Time 14, idle 182216/s, free 71904, MQTT 1(1), bWifi 1, secondsWithNoPing -1, socks 2/38

After this, MCU disconnect ground from the module. It is possible to make easy modification: bypass ground from the module (pin 9 on CB3S) to BAT- contact, use tuyaMCU driver and try to use FW deep sleep mode.
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#42 20768091 12 Oct 2023 17:51

DeDaMrAz DeDaMrAz

Level 22

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Post #42
20768091 12 Oct 2023 17:51

@dgel27

Go to config, enable WiFi quick connect (flag 37). Also, decrease "Uptime seconds required to mark boot as ok:" from 5 to 3. You can also set up a static IP address for your device, which will help it boot faster and connect to your WiFi faster. This way, the timeout TuyaMCU is imposing will be enough, and your values/states will be reported.

Hope this helps, and sorry for the late response.

If you like my work, support me at: https://paypal.me/openshwprojects
#43 20815488 14 Nov 2023 21:46

rickbronson rickbronson

Level 3

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Post #43
20815488 14 Nov 2023 21:46

I read all the posts and found that I DID NOT need to unsolder anything to do the UART flashing. You can read all about my experience here: https://github.com/rickbronson/Open-Source-So...re-on-a-Tuya-TH01-Temperature-Humidity-Sensor

Cheers,

Rick
#44 20845229 03 Dec 2023 21:56

emrecetinkaya86 emrecetinkaya86

Level 4

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Post #44
20845229 03 Dec 2023 21:56

Hi,

I don’t get any battery state. Is it not a feature of the device or am I missing something?

Thanks
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#45 20845231 03 Dec 2023 21:58

p.kaczmarek2 p.kaczmarek2

Moderator Smart Home

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Post #45
20845231 03 Dec 2023 21:58

What is your device configuration? You will not get battery state entry unless you configure it

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

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#46 20845669 04 Dec 2023 10:23

emrecetinkaya86 emrecetinkaya86

Level 4

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Post #46
20845669 04 Dec 2023 10:23

Hi,

I just added those to startup commands, do i need to add anything for battery?:

backlog startDriver tuyaMCU; startDriver tmSensor; linkTuyaMCUOutputToChannel 1 val 1; setChannelType 1 temperature_div10; linkTuyaMCUOutputToChannel 2 val 2; setChannelType 2 Humidity;linkTuyaMCUOutputToChannel 3 val 3; setChannelType 3 ReadOnly;

Kind regards
#47 20845707 04 Dec 2023 10:49

p.kaczmarek2 p.kaczmarek2

Moderator Smart Home
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Post #47
20845707 04 Dec 2023 10:49

So channel 3 is battery level? As in Low-Mid-High?
So change:
Code: text Expand Select all Copy to clipboard
setChannelType 3 ReadOnly;

To:
Code: text Expand Select all Copy to clipboard
setChannelType 3 LowMidHigh;

See channel type docs at:
https://github.com/openshwprojects/OpenBK7231T_App/blob/main/docs/channelTypes.md

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

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#48 20845783 04 Dec 2023 11:38

emrecetinkaya86 emrecetinkaya86

Level 4

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Post #48
20845783 04 Dec 2023 11:38

Ok i will. Thank you very much!
#49 20845795 04 Dec 2023 11:46

p.kaczmarek2 p.kaczmarek2

Moderator Smart Home

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Post #49
20845795 04 Dec 2023 11:46

Keep in mind that you need to redo HASS discovery after changing the channel type.

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

Helpful post? Buy me a coffee.
#50 20845859 04 Dec 2023 12:40

emrecetinkaya86 emrecetinkaya86

Level 4

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Post #50
20845859 04 Dec 2023 12:40

I did and also HA discovery. The 3rd channel's value is either 0, 1, or 2. I think it's equal to low-mid-high.
#51 20873676 23 Dec 2023 15:54

divadiow divadiow

Level 38

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Post #51
20873676 23 Dec 2023 15:54

I've just bought two of these and my variants are CBU module and AHT30 sensor.

I see no AHT30 search results yet on elektroda. I am away and cannot flash at the moment, but has anyone played with this type?

My initial searching has found no mention of AHT30 on Aosong site. I've unsuccessfully tried to guess the URL of the datasheet, using a modified file name of the AHT20 pdf and URL.
#52 20873691 23 Dec 2023 16:05

p.kaczmarek2 p.kaczmarek2

Moderator Smart Home

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Post #52
20873691 23 Dec 2023 16:05

have you tried SHT30 driver?

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

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#53 20904677 12 Jan 2024 07:36

sevastianovv sevastianovv

Level 5

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Post #53
20904677 12 Jan 2024 07:36

Good afternoon. Tell me, data is sent to MQTT 2 times. How to fix it?
#54 20904822 12 Jan 2024 09:35

p.kaczmarek2 p.kaczmarek2

Moderator Smart Home

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Post #54
20904822 12 Jan 2024 09:35

Why is it a problem? Which device config?

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

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#55 20904927 12 Jan 2024 10:35

sevastianovv sevastianovv

Level 5

Post #55

20904927 12 Jan 2024 10:35


startDriver TuyaMCU
startDriver tmSensor

// may be needed, depends on device, some also use 9600
tuyaMCU_setBaudRate 115200

// dpID 1 is tempererature div 10
setChannelType 1 temperature_div10
linkTuyaMCUOutputToChannel 1 val 1
// dpID 2 is % humidity
setChannelType 2 Humidity
linkTuyaMCUOutputToChannel 2 val 2
// dpID 3 is battery state - low(0), mid(1) and high(2)
linkTuyaMCUOutputToChannel 3 enum 3
setChannelType 3 ReadOnly
setChannelLabel 3 Battery
//
// setup dpCache - temperature interval
//
// Show textfield for that
setChannelType 5 TextField
// setup display name
setChannelLabel 5 Temperature Interval
// Make value persistant (stored between reboots), 
// start value -1 means "remember last"
SetStartValue 5 -1
// set default value if not set
if $CH5==0 then setChannel 5 1
// link dpID 17 to channel 5, the type is val, extra '1' means that its dpCache variable
linkTuyaMCUOutputToChannel 17 val 5 60

setChannelType 6 TextField
setChannelLabel 6 Humidity Interval
SetStartValue 6 -1
if $CH6==0 then setChannel 6 1
linkTuyaMCUOutputToChannel 18 val 6 60


12:35:37 917		BK7231N_8587000B2/6/get	0.000000
12:35:36 931		BK7231N_8587000B2/5/get	0.000000
12:35:35 927		BK7231N_8587000B2/3/get	1.000000
12:35:34 934		BK7231N_8587000B2/2/get	20.000000
12:35:33 922		BK7231N_8587000B2/1/get	26.200000
12:35:32 925		BK7231N_8587000B2/ip	192.168.1.213
12:35:31 937		BK7231N_8587000B2/freeheap	73024
12:35:30 932		BK7231N_8587000B2/uptime	12
12:35:29 935		BK7231N_8587000B2/rssi	-55
12:35:28 935		BK7231N_8587000B2/sockets	2
12:35:28 294		BK7231N_8587000B2/ssid	434343434
12:35:27 734		BK7231N_8587000B2/3/get	1.000000
12:35:27 526		BK7231N_8587000B2/2/get	20.000000
12:35:27 310		BK7231N_8587000B2/1/get	26.200000
12:35:26 951		BK7231N_8587000B2/mac	a0:92:08:89:87:89
12:35:25 933		BK7231N_8587000B2/build	Build on Jan 4 2024 11:21:20 version 1.17.391
12:35:24 935		BK7231N_8587000B2/host	obkN_8587000B2
12:35:24 301		BK7231N_8587000B2/connected	online

#56 20905032 12 Jan 2024 11:23

p.kaczmarek2 p.kaczmarek2

Moderator Smart Home

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Post #56
20905032 12 Jan 2024 11:23

This config looks ok. My only question would be now why do you think it's a problem? You can try disabling "broadcast self state on MQTT connect" if you really want to, but in my opinion, there is no problem with device broadcasting data twice.

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

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#57 20905557 12 Jan 2024 15:57

sevastianovv sevastianovv

Level 5

Helpful post? (+1)

Post #57
20905557 12 Jan 2024 15:57

good afternoon. Yes, I did it on your advice, thank you. there is another question in mqtt, the data comes BK7231N_AC4D000A3/1/get 27.000000 how to get rid of zeros and leave 27.00
#58 20910745 15 Jan 2024 14:20

Wen2024 Wen2024

Level 7

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Post #58
20910745 15 Jan 2024 14:20

I tried to flash TH01 with bk7231flasher_1.1.6 like auntlydia and rickbronson did. I use external 3.3V power supply. I connect +3.3V to TH01, GND to TH01 GND and USB-UART ground, TH01 RX2 to USB-UART Tx and TH01 TX2 to Rx USB-UART. (See photo). I powered TH01 on and off or shorted TH01 CEN to ground. All without success. Always got: "Getting bus failed, will try again...". I changed USB-UART (CH340, FTDI). I tried different baud rates. Please help!
#59 20911136 15 Jan 2024 18:27

p.kaczmarek2 p.kaczmarek2

Moderator Smart Home

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Post #59
20911136 15 Jan 2024 18:27

Did you cut the connection to MCU? Few posts above user described the procedure well.
https://www.elektroda.com/rtvforum/topic3968377-30.html#20628188

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

Helpful post? Buy me a coffee.
#60 20911152 15 Jan 2024 18:36

Wen2024 Wen2024

Level 7

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Post #60
20911152 15 Jan 2024 18:36

No, I didn't because of Aunt Lydia's post: "I desoldered it for the reason that I was not able to get the device's created WiFi AP up and running long enough to enter configuration - simply because I was not patient enough. It is not necessary, don't do it, you don't need to. It was taking ages to desolder the battery pins, which was necessary in order not to melt the housing..." and Rick Bronson's post: "I read all the posts and found that I DID NOT need to unsolder anything to do the UART flashing...."
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Topic summary

✨ The discussion centers on the teardown, firmware flashing, and configuration of the TH01 generic temperature and humidity sensor, which uses a BK7231N WiFi module and a TuyaMCU microcontroller (MCU) managing sensor data and power. Users report challenges flashing the device due to the MCU controlling power to the WiFi module and UART lines being connected between MCU and WiFi module, requiring either cutting UART traces, desoldering the MCU or WiFi module, or powering the WiFi module externally during flashing. The TuyaMCU driver in OpenBK7231N firmware is essential for communication, with dpIDs 1 and 2 corresponding to temperature (divided by 10) and humidity, and dpID 3 likely representing battery state (low, mid, high). Proper autoexec.bat configuration involves starting TuyaMCU and tmSensor drivers, linking dpIDs to OBK channels, and setting channel types accordingly. MQTT integration is commonly used for data reporting, with some users noting duplicate MQTT messages and template adjustments needed for value formatting. Battery-powered operation requires the MCU to cycle power to the WiFi module to conserve energy, so powering the WiFi module externally can prevent data reporting. Flags such as WiFi quick connect and static IP improve connection stability. Some users successfully flash without desoldering by cutting UART traces and powering the WiFi module directly. The community shares detailed pinout photos, flashing procedures, and configuration scripts. Variations in PCB versions and sensor chips (AHT20, AHT30, CHT8315) affect driver selection and configuration. Deep sleep and wakeup configurations are discussed for battery life optimization. Tools like TuyaMCUAnalyzer assist in decoding UART communication. Issues with MQTT hostname configuration can prevent MQTT startup, and firmware updates have improved battery device support. The thread also covers troubleshooting WiFi connectivity, log inspection via WebUI, and Home Assistant integration challenges.
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FAQ

TL;DR: “Latest OBK builds extend battery life by up to 60 %” [Elektroda, p.kaczmarek2, post #20588135] “You flash it as usual” [Elektroda, p.kaczmarek2, post #20582789] Flash success rises when RX/TX lines to the Tuya MCU are isolated. Why it matters: you can turn a €6 TH01 into a cloud-free, Home-Assistant-ready sensor in under 10 minutes.

Quick Facts

• MCU type: BK7231N-QFN32 on CB3S module; 2 MB flash [Elektroda, Wen2024, post #20931316] • Default Tuya baud: 115 200 bps (some boards use 9 600 bps) [Elektroda, BAGZZlash, post #21552797] • Typical dpIDs: 1 = Temp×10, 2 = RH%, 3/101 = Battery enum [Elektroda, anthonythomas, #20516557; doudouni100, #21441634] • Max OBK channels per build: 64 [Elektroda, doudouni100, post #21441842] • Cost of TH01 board: €5–8 retail (2025 AliExpress listings)

1. Which TH01 hardware variants are confirmed?

A. AHT20 + TuyaMCU + BK7231N (earliest batch). B. AHT30 or CHT8310 directly on I²C and no TuyaMCU. C. Shield-less CB3S with 115 200 bps TuyaMCU [Elektroda, divadiow, #20873676; vinibali, #21398650].

2. Do I need to cut anything before flashing?

Yes, if a TuyaMCU is present you must sever its RX1/TX1 to stop it driving the bus. Options: 1) cut two thin traces and later bridge, 2) lift or desolder the CB3S, 3) lift the SOIC-8 MCU [Elektroda, p.kaczmarek2, post #20626343] Boards without TuyaMCU flash directly.

3. What baud rate should I select in BK flasher?

Most TuyaMCU revisions answer only at 115 200 bps; older ones use 9 600 bps. If logs show no “55 AA” packets switch rates accordingly [Elektroda, BAGZZlash, post #21552797]

4. What is the minimal working autoexec.bat for classic TH01?

backlog startDriver TuyaMCU; startDriver tmSensor; tuyaMCU_setBaudRate 115200; setChannelType 1 temperature_div10; linkTuyaMCUOutputToChannel 1 val 1; setChannelType 2 Humidity; linkTuyaMCUOutputToChannel 2 val 2; setChannelType 3 LowMidHigh; linkTuyaMCUOutputToChannel 3 enum 3

This publishes temperature, humidity and battery level [Elektroda, anthonythomas, post #20516646]

5. How do I map battery when the dpID is 101?

Use a lower OBK channel number, e.g. linkTuyaMCUOutputToChannel 101 enum 10 then setChannelType 10 LowMidHigh to stay within the 64-channel limit [Elektroda, doudouni100, post #21442987]

6. MQTT shows duplicates—problem?

OBK broadcasts once at connect and once on value change; disable “Publish self state on connect” to halve traffic [Elektroda, p.kaczmarek2, post #20905032]

7. Can I run without any MQTT broker?

Yes. Leave the MQTT host field blank or add tuyaMcu_defWiFiState 0x04; OBK then skips the MQTT-wait state and still logs locally [Elektroda, p.kaczmarek2, post #20931402]

8. How do I extend battery life?

Update to OBK ≥1.17.391 (quick connect + static IP gives ~60 % longer runtime) [Elektroda, p.kaczmarek2, post #20588135] 2. Set Wi-Fi quick connect flag 37 and reduce boot-OK timer from 5 s to 3 s [Elektroda, DeDaMrAz, post #20768091] 3. Increase sensor sleep with AHT2X_Cycle 255 (≈4 min) [OBK docs].

9. Why do I only get zeros on channels?

Causes: a) wrong dpIDs for your PCB; capture UART with TuyaMCUAnalyzer to confirm [Elektroda, Wen2024, post #20922691] b) Baud mismatch—see Q3. c) Device waiting for MQTT—see Q7. A faulty trace gives the same symptom; verify continuity.

10. Flashing stops at 75 % with “buffer contains data”. Fix?

Lower speed to 460 800 bps or swap USB-UART; some hosts drop at 921 600 bps [Elektroda, vinibali, post #21398650] Disconnect MCU lines before retrying.

11. How can I change the reporting interval?

For direct-I²C builds run AHT2X_Cycle <seconds> (1-255 sec). Battery-powered TuyaMCU boards expose dpIDs 17/18 (intervals); link them to TextField channels and set desired value, then send with linkTuyaMCUOutputToChannel 17 val 5 60 [Elektroda, grericht, post #20628188]

12. Edge case: device doesn’t wake after deep discharge.

Below 1.8 V the BK7231 may brown-out and corrupt flash; keep a 2 × AAA pack above 2 V or recharge Li-coin cells promptly. Full 2 MB backup allows recovery with full-erase reflashing [Elektroda, insmod, post #21552919]

13. Quick 3-step flashing guide (TuyaMCU boards)

Cut RX1/TX1 between MCU and CB3S; solder four wires to 3 V3, GND, RX, TX. 2. Hold CEN low, flash OBK at 115 200 bps, then restore traces. 3. Power CB3S from bench 3 V3, configure Wi-Fi + autoexec, fit batteries, close case [Elektroda, auntlydia, post #20684096]

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