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    Calibration BME688

    Calibration BME688

    NBG
    New Poster

    Hi,

    Im using the sensor BME688 with the BME688-API but I'm not using BSEC software. When I run my device, the temperature value is two degrees above the actual temperature. What should I do to calibrate my sensor?

    Thanks.

    5 REPLIES 5

    BSTRobin
    Community Moderator
    Community Moderator

    Hello NBG,

    1.Did you use BME688 sensor API on github? https://github.com/BoschSensortec/BME68x-Sensor-API
    2.Did you have temperature log data for actual temperature and BME688 temperature?

    Hi BSTRobin,

    1. Yes, I used the API on github.

    2.Yes, I have an external thermometer, which I used to compare the values, and the result of the BME688 with my own device.

    BSTRobin
    Community Moderator
    Community Moderator

    Hello NBG,

    By comparing bme280, we found no difference of two degrees.

    BME280 temperature:

    BME280.png

    BME688 temperature:

    BME688.jpg

    Sensor API already has temperature compensation.

    BME688 temperature measurement.png

    kmca
    Established Member

    I have three BME 688 and they all read ~2 degrees C higher at room temp.  Side by side they vary by around 0.5 degree

    I believe that the temperature compensation is to allow for the heater, and these are essentially non-calibrated devices.  The IRR filter averages values so smooth's the values, but will do nothing for the offset. 

    Most Python wrappers (PI3G ) have added a temp_offset value to be subtracted ( its always high from the heater and electronics) from the API values. I hilariously tried (and failed) using ice and a boiling kettle , but you really need to compare to a calibrated thermometer across a range of temps once your device is in steady state. 

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