I2C SHT21 Calibration

General Discussion
1

Basic Information:

Printer Model: 2.4
MCU / Printerboard: Manta M8P
Host / SBC: CM4

Describe your issue:

A currently working i2c SHT21 sensor. Wired into a Sunlu S4 drybox.

The issue is that the humidity in Mainsail displays at 0% - it should be around 16%. The temperature is accurate. (I have two other temp/humid sensors in the dry box.

Question: Is there a way to apply a calibration curve or bias?

[temperature_sensor Filament_Dryer]
sensor_type: SHT21
i2c_mcu: host
i2c_bus: i2c.1
htu21d_resolution: TEMP11_HUM11
htu21d_report_time: 20

[gcode_macro QUERY_TEMP]
gcode:
    {% set sensor = printer['htu21d Filament_Dryer'] %}
    M117 Temp:{sensor.temperature} Humidity:{sensor.humidity}
        {action_respond_info(
        "Temperature: %.2f C\n"
        "Humidity: %.2f%%" % (
            sensor.temperature,
            sensor.humidity))}

…

2

No way, aside from code modification.
If you use your macro to monitor humidity - then you can apply that logic there.

Thats it.

FWIW, I think just use the better sensor, I do not see a way to compensate bad humidity values as high as you mention.

3

Yeah, that’s what I thought. $3 sensor, so what else would I get> :slight_smile: