I2C sensors

[nagyrobi]

Would it be possible to add software support for example SHTC3 (high precision temperature and humidity sensor) or MAX44009 (ambient light sensor) both on I2C bus. All it needs to do is publish to an MQTT topic the value of the sensors at regular time interval, say, at every 30 seconds.

I'm specifically looking at Lanbon L8. It has an analog temp sensor by factory, but that kind is quite unreliable and needs calibration. The ambient light would be useful to locally control display backlight/brightness. I'm thinking to solder directly to the module's I2C terminals (parallel with the touch controller), as the sensor uses a different I2C address, it's perfectly feasible.
Or, at least, have a 1-wire DS18B20 instead of the analog one, soldered in place.

[fvanroie]

Hi, thanks for the interest in hasp-lvgl. In hasp-lvgl -at the moment- custom sensors will require you to build a custom firmware. Adding the needed libraries and wrapper code should be straight-forward.

There are also a lot of projects that handle custom temperature sensors already, like tasmota, espHome, etc... Our focus is currently on the hardware in the supported devices and built-in sensors for the pre-built firmware files.

The potential number of sensors is huge, so I'd like to find out which particular ones would warrant built-in support. When a sensor is widely used or present in multiple touchscreen devices, we can reconsider.

I do like the idea to have support for common sensors, but for the time being it is on the back-burner.

[netmikey]

being dependent on another project also has some drawbacks

Yes indeed. In the end, it's a cost/benefit question.

The problem is that openHASP relies heavily on ArduinoJSON 6 and ESPHome ships with an old custom ArduinoJSON 5 library

Oh I see. Maybe we could motivate the ESPHome project to move to ArduinoJSON 6 if that would pave the way for openHASP on ESPHome?

[fvanroie]

I have only looked into this briefly and didn't dig much deeper into it. From what I understand on the ESPHome Discord channel, that library was modified a long time ago by the original creator and now no-one really knows what was changed...

I'd be happy to revisit this when the ESPHome ArduinoJson version has been updated. I do have hopes that Nabu Casa will eventually come around to updating the library. Or if some people would take this up as a sprint. Maybe other ESPHome projects would also profit from such an update.

Maybe it's even possible to run two distinct versions side-by-side using namespaces.... but I'm not experienced in that.

[nagyrobi]

For sensors, I think a custom code folder might be possible. There you can put your own functions which hook into openHASP. The folder would be kept out of version control, so you can update the project files and it will recompile with the customizations...

That sounds awesome! How about re-using Tasmota's xsns_*.ino sensor drivers? Each sensor type is in a different file, gets loaded from user_customize. It's already preparing the MQTT payload and the display of the value on the web interface straight from the driver.

We need it to appear in the GPIO dropdowns, so it can be assigned and bang...

[fvanroie]

There are way too many dependencies on headers and other files/libraries to have a drop-in .ino automagically work...
You could add a wrapper yourself if needed... but for now I was just thinking of proper Arduino libraries.

[fvanroie]

A proof-of-concept LVGL component for ESPhome can be found here: https://github.com/fvanroie/esphome-lvgl.

[fvanroie]

You can add #define HASP_USE_CUSTOM 1 to your include\user_config_override.h.
Copy the default template files as my_custom.h and my_custom.cpp

This will add the custom\my_custom.h header to openHASP compilation and call the defined functions from the main loop...

[kydang789]

Would it be possible to add software support for example SHTC3 (high precision temperature and humidity sensor) or MAX44009 (ambient light sensor) both on I2C bus. All it needs to do is publish to an MQTT topic the value of the sensors at regular time interval, say, at every 30 seconds.

I'm specifically looking at Lanbon L8. It has an analog temp sensor by factory, but that kind is quite unreliable and needs calibration. The ambient light would be useful to locally control display backlight/brightness. I'm thinking to solder directly to the module's I2C terminals (parallel with the touch controller), as the sensor uses a different I2C address, it's perfect
EM20918_code.zip
ly feasible. Or, at least, have a 1-wire DS18B20 instead of the analog one, soldered in place.

WT32-SC01 has this sensor. Also code for this, did you try?
EM20918 Datasheet 2019 Oct.pdf
EM20918_code.zip

[nagyrobi]

You could re-use the RX and TX pins, but that also requires disabling the serial console (which is pretty useless anyway when mounted in the wall). @fvanroie is it enough to set #define HASP_START_CONSOLE 0 to free up these pins?

[nagyrobi]

I just finished doing calibration measurements on a batch of DS18B20 and SHTC3 and must say I'm impressed of the second:
https://a.aliexpress.com/_mrhJsHO

How difficult would it be to remap RX and TX (in Lanbon) as a secondary I2C bus?

[fvanroie]

HASP_START_CONSOLE only prevents reading from RX. TX will still output the logs.
HASP_USE_SERIAL would be needed to turn off serial communications completely...

[nagyrobi]

That will free up the RX/TX pins?

[fvanroie]

possibly... HASP_USE_SERIAL is just a suggestion, it's not available at this point.
Serial is always active atm, whether you need it or not.

[samturner3]

@nagyrobi how did you go with this? I am in same boat, I want to add I2C devices to Lanbon L8.

Also coding in my_custom.h and my_custom.cpp solder directly to the module's I2C terminals (parallel with the touch controller).
Only thing I can not think of is how to hook into existing I2C bus used for touch controller, rather than initiate a new from a lib we include ourselves, as obviously it is already running from stock firmware for the screen.

Found these functions in file include/lv_drv_conf.h from stock firmware.

I'm guessing we somehow need to access these from our custom code?

(I have not tried anything yet)
I can't see how to access that instance from just the custom_* functions.

If you did do it, do you have code example you could share?
Or @fvanroie have any suggestions?

If not doable via custom code, maybe a modification to the firmware (slightly out of my depth); or ideally exposing these so it can be done via custom code?

[nagyrobi]

I gave up on this idea, went with Xiaomi LYWSD03MMC running pvvx firmware, much better approach system-wise, as you can place the sensors anywhere - in optimal measurement locations - which usually can't be done with a touch screen.

Pricewise they are attractive and I can receive the signal of 10 such sensors from all around the house via a single, Ethernet-based ESPHome node reliably.
Battery seems to last long indeed, I run them for 5 months now, and currently at 75-80%.

[fvanroie]

I think you can just use #include <Wire.h> and then use the global Wire object with the appropriate address:

    do {
        Wire.beginTransmission(I2C_ADDR); 
        Wire.write(addr); 
        Wire.endTransmission(false); // Restart
        delay(10); 
        rdDataCount = Wire.requestFrom(I2C_ADDR, 1); 
    } while(rdDataCount == 0); 
    while(Wire.available()) {
        rdData = Wire.read(); 
    }

The touch driver initializes the bus in src\drv\touch\touch_driver_ft6336u.h. You should be able to use it in the custom code too.

If it doesn't work, you could use Wire1 on separate pins to initialize the secondary I²C bus with your own config.

[flexiti]

I am using ESP32-4848S040 (Does anyone have schematic ?)
I think the advice @fvanroie is ok, in this device you need to use the pin SDA =19 and SCL = 45
The transmission speed is set to 400000
I need to check whether this I2C bus works at 3V or 5V logic
Has anyone managed to connect something in parallel with G911 touch sensor??
I will try to connect BMP280 or BME280

-D TOUCH_DRIVER=0x911
    -D TOUCH_WIDTH=480
    -D TOUCH_HEIGHT=480
    -D TOUCH_SDA=19
    -D TOUCH_SCL=45
    -D TOUCH_RST=-1
    -D TOUCH_IRQ=-1
    -D I2C_TOUCH_FREQUENCY=400000
    -D I2C_TOUCH_ADDRESS=0x5D ; or 0x14
    -D I2C_TOUCH_PORT=1

[flexiti]

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