Inaccurate relative humidity reading from BME680

[Sunilvignesh]

Hello there,

I'm working with the BME680 sensor with `https://github.com/boschsensortec/BSEC-Arduino-library/blob/master/examples/basic_config_state/basic...`

The temperature value seems to close (varying between 0.5-0.8 Degree C) and the relative humidity is off by 10-12%, I'm comparing the values with the off-the-shelf available temp/humidity sensor.

Hardware setup:

Sensor: https://www.amazon.in/CJMCU-680-Temperature-Humidity-Ultra-Small-Development/dp/B07K1CGQTJ

MCU: ESP32 Node MCU

Software Setup:

Platform: Arduino IDE v2.3.2

BSEC Software Library: v1.8.1492

Output:

```

BSEC library version 1.4.9.2
Erasing EEPROM
Timestamp [ms], IAQ, IAQ accuracy, Static IAQ, CO2 equivalent, breath VOC equivalent, raw temp[°C], pressure [hPa], raw relative humidity [%], gas [Ohm], Stab Status, run in status, comp temp[°C], comp humidity [%], gas percentage
1054, 50.00, 0, 50.00, 600.00, 0.50, 35.14, 99147.20, 43.73, 30955.43, 1.00, 0.00, 35.14, 43.73, 0.00
4054, 50.00, 0, 50.00, 600.00, 0.50, 35.14, 99146.00, 43.35, 32052.47, 1.00, 0.00, 35.03, 43.62, 0.00
7054, 50.00, 0, 50.00, 600.00, 0.50, 35.17, 99147.02, 43.01, 33230.12, 1.00, 0.00, 35.06, 43.22, 0.00
10054, 50.00, 0, 50.00, 600.00, 0.50, 35.16, 99144.79, 42.72, 33605.90, 1.00, 0.00, 35.05, 42.94, 0.00
13054, 50.00, 0, 50.00, 600.00, 0.50, 35.16, 99147.86, 42.52, 34670.09, 1.00, 0.00, 35.05, 42.76, 0.00
16054, 50.00, 0, 50.00, 600.00, 0.50, 35.16, 99145.57, 42.46, 35020.29, 1.00, 0.00, 35.06, 42.70, 0.00
19054, 50.00, 0, 50.00, 600.00, 0.50, 35.18, 99145.80, 42.40, 35650.48, 1.00, 0.00, 35.07, 42.60, 0.00
22054, 50.00, 0, 50.00, 600.00, 0.50, 35.17, 99147.01, 42.42, 35989.71, 1.00, 0.00, 35.06, 42.65, 0.00

```

[BSTRobin]

Hi Sunilvignesh,

From the log you posted, it only contains the RAW temperature and RAW humidity data of BME680, as well as the compensated temperature and humidity data.

Usually, this requires recording and comparing the temperature and humidity data of BME680 at the same time, as well as the temperature and humidity data of testing equipment in the laboratory environment, to determine whether the temperature and humidity data output by BME680 is inaccurate.

[Sunilvignesh]

To give you the context, I've the off-the-shelf temperature and the humidity sensor from Mi, when comparing the compenstated temperature and the humidity from the sensor, the temperature reading is off by 5-10 degree C and the humidity is around 10-12%.

I would like to understand, how can I determine the generalised offset to get the right compenstated temp/humidity value.