[BKN7231N CBU] Universal remote control with temperature and humidity sensor

Bought from here:
https://www.aliexpress.com/item/1005004762491352.html
Aliexpress page cache:


Almost same as https://www.elektroda.com/rtvforum/topic3933390.html, but with added temperature and humidity sensor











Used GPIO pins are:
P15 - Power IR receiver
P17 - Red LED
P9 - Green LED
P28 - Reset button
P24 - IR receiver input
P26 - Sensor SCL
P6 - Sensor SDA
P7 - Sensor Alert
P8 - IR send

Temperature and humidity sensor is CHT8305. Datasheet is here:
http://www.lanftek.com/Data/lanftek/upload/file/20180618/201802281014097175.pdf

Hello, maybe it's SHT30? With I2C and an alert line? What do you think, @dheenhasty ?

Maybe you could try assigning SHT roles to the pins, with 3 pins and 2 roles, there are not many combinations to try...

I found it. It's CHT8305.
Unfortunately, I'm new with OpenBK7231N and still I don't know how to configure it for this device.
Does OpenBK7231N support CHT8305?

Yes, just set the correct pin roles for SDA and SCL, furthermore, set first channel for SDA to 1 and second to 2 or smth like that.
Btw:
https://github.com/openshwprojects/OpenBK7231T_App/tree/main/docs
Search for CHT8305 in the page below:
https://github.com/openshwprojects/OpenBK7231T_App/blob/main/docs/ioRoles.md

GUI flasher doesn't work with my Debian Linux with several USB to TTL converters.
Flashed successfully with uartprogram.
I set pins for IR Send and Receive, also for CHT8305, but no data is appeared in the logs. Seems the driver is not yet finished.
I'll check again pin numbers and functions.
How to check CHT8305 and IR send/receive with HomeAssistant?

I want to sincerely thank you @p.kaczmarek2 for your work on OpenBeken!

I'm new to this forum and am also trying to use it on this same device. I have read your suggestions @p.kaczmarek2 but I too am unable to get this ir blaster /temp/humidity sensor to function.
@ststefanov Could you share some screenshots of your settings? I'm confused about what I should put for P15 and P24 for instance since they both deal with the IR Receiver function. Also I don't know how to input P7.

Thank you both for your help. I sincerely appreciate it.

Added after 5 [minutes]:

This is my current configuration (which doesn't work)

Setting CLK and DAT pins for CHT8305 should be enough, but of course you also have to restart.. Then you can also make sure to set two different channels for DAT pin, first will store humidity, second temperature.
If CHT8305 is not responding, then you might have chosen incorrect GPIO.
Check with multimeter which GPIOs are connected to CHT8305. Consult documentation of WiFi module/chip if needed.
CHT8305 driver was tested and reported to be working by our users in the past.

To check IRRecv, set correct pin for IRRecv, restart device, and open Web Application->Log and look at logs while pressing remote button.


@strone8 , you need to check with multimeter or by following traces, where the IRReceiver/sender are connected. What do you mean with "both pins deal with receiver function"? The IRRecv is just a single pin. What is the role of P7 in case of your device?

>>20485957
Seems like cht has an alert mode too but less complex than the sht
Both are really similar.

Thank you @p.kaczmarek2 so much. I did follow your steps in tracing and I am sure that I was initially wrong and P24 is actually the IRRecv pin from multimeter tracing.

For some reason I am not seeing any changes in the logs with IR remote presses despite having all logging features and levels fully enabled. I have some familiarity with this procedure on a separate device previously in Tasmota using an ESP8266.

@ststefanov had listed "P15 - Power IR receiver" and "P24 - IR receiver input" and I am still unsure how to address "P15 - Power IR receiver" in the settings or if that's even necessary.

Following @ststefanov I tried both the CHT SDA (P6) and CHT SCK (P26) as well as Soft SDA (P6) and SoftSDL (P26) and even with channel 1 and channel 2 selected for P6, I am getting "0.00" information for each.

Any advice you can give would be greatly appreciated.

Added after 12 [minutes]:

An update: @dheenhasty thank you! I changed from CHT to SHT and I am now getting activity. The readings are totally off: I am 21C with 27% humidity but at least I have somewhere to start looking for calibration.

The value you got is the défaut value of the driver, i think you have a bad pin définition and this does not tell you you have a sht

There close, but the i2c command is not the same.

P15 is used as output to power IR receiver. Probably this is done to save power when the receiver is not needed.
To receive IR signals we must first set P15 to 1, this will power up the receiver and all will work. Here is the part of the schematics:


@strone8, I still don't have working configuration. Changing to SHT gives unreal results because of wrong sensor type. Calibration will not work here.

I think there is a problem with CHT8305 support, because when I set SDA and SCL for example for SHT I see 2 drivers active. When I set them for CHT I see only one driver active.

Edit (after some trials): Seems that driver for CHT8305 is not started (may be bug?). I enabled RAW TCP connection and using telnet start the driver manually:

Now everything is working fine!



Unfortunately, after restart the driver was not started. I don't know if this is bug or feature. To start automatically the driver in startup command line I added:


Now after system restart the driver is started and works OK.

You are indeed correct. Well done, I was not aware about this little issue. The autostart of CHT8305 driver was indeed missing, most likely the CHT8305 driver contributor didn't include this in his pull request.

I have fixed it now and the new release will up and running within next 15 minutes. Thank you for reporting, @ststefanov

Thank you!
Next step is to make device to learn IR commands from existing remote, save them in memory and send them when needed.
Something as a virtual IR remote.
Is there some guides on this topic?

Just want to thank you both @p.kaczmarek2 and @ststefanov. My unit is reading temperatures with the updated firmware.

Please excuse my ignorance. I tried setting P15 to 1 from 0 and switching the role to power but I must be doing something wrong.
I saw the schematic do I need to make a physical change or software?
Thank you again!

If you want P15 to be High all time, just set the pin role to "AlwaysHigh". Then it will always have a 3.3V on it.
https://github.com/openshwprojects/OpenBK7231T_App/blob/main/docs/ioRoles.md

@p.kaczmarek2 thank you!!!

It was made intentionally this way. The IR receiver is used only in the learning process, which takes a very small amount of time compared to working time. All other time it is switched off to not consume power.
If you like, you can assign LED or RELAY to P15 and switch it ON manually before learning. After learning is finished you can switch it off manually.

I'm still searching how to learn and reproduce IR codes for air conditioning systems, for example.

Thank you both so much for your replies! @ststefanov I'd like to hear about your progress and I'll share mine. I appreciate your help immensely

There is a WIP IR library extension but someone must look into flash memory issue on N platform:
https://github.com/openshwprojects/OpenBK7231T_App/pull/723
Do anyone know how much power in reality that IR turn off really saves?

In the TSPO1738 datasheet typical current is 5mA, which means 16.5mW wasted (on more time) power. Another idea why they made this way is that along power saving most important is to switch off receiver when send IR commands. Due to high power of transmitter receiver always repeats sent IR signal and may be this created problems in the system. Powering from GPIO allows to enable and disable the IR receiver easily.

Added later:
May be the most important reason to keep things cool as much as possible is the presence of a thermo-sensor in the same case.

Unfortunately my device is not responding anymore, maybe I fried it.
So, when I have a new one I will continue with IR codes. Current device will be transformed in Tasmota with ESP-12F module.

@ststefanov Hope the other one works well for you and thank you for the guidance.

Mine is still working and I initially thought about going the same route as you. I'm using the GPIO power set as a relay for IR learning and have the Red LED on to indicate that it's in that mode, with the green LED having inverted logic to indicate WiFi connection.

I have a combination IR/RF Blaster (UFO-R2-RF) that I had to put an ESP8266 module into because it came with a WR3E module that currently isn't supported with OpenBeken or Tasmota.

I need to investigate the RF portion on the UFO that I was having trouble with. The IR portion is always on but I believe the RF is GPIO powered so I will test that.

To compliment the CHT driver, a CHT_Cycle command has been added with 1.17.119 build - usage:

//CHT_Cycle (sample time in seconds)
CHT_Cycle 60

You can add this in autoexec.bat script and adapt to your needs.