different readings from neighboring BME680 sensors

[yenigun]

We have 3 BME680 sensors sitting 10cm apart from each other. These are fresh new sensors (no calibration before), being read every 60 secs by using ESP8266 through BSEC library.

As you can see from the plot, we get different IAQ readings from these sensors, even when the accuracy is reported to be 3 by all of them (see e.g. the range between hours 1.5 and 2).

Any idea why such different IAQ values could be reported by these sensors?

Thanks in advance.

[BSTRobin]

Hi yenigun,

From your test results, the accuracy is reduced from 3 to 2 some time. The accuracy of 2 means that the sensor needs to be calibrated to improve performance. The sensor has the best performance until the accuracy is 3.

In addition, for your test "3 BME680 sensors sitting 10cm apart from each other", if not in a strict test environment, the air that the sensor contacts is different, and the sensor readings are also different.

[ilcnet]

Hello dear BSTRobin when we use bsec2 example codes to calibration, when the sensor is in 3 accuracy level, the state was save automatically in eeprom? Or with rebooting all of the accuracy levels will be Los and delete? Regard

[BSTRobin]

Hi ilcnet,

Calibration status is not automatically saved. Usually our example code includes the code for saving state and loading state.
https://github.com/BoschSensortec/Bosch-BSEC2-Library/blob/master/examples/generic_examples/basic_co...

/**
* @brief : This function retrieves the existing state
* @param : Bsec2 class object
*/
bool loadState(Bsec2 bsec);

/**
* @brief : This function writes the state into EEPROM
* @param : Bsec2 class object
*/
bool saveState(Bsec2 bsec);