Hi everyone! We use BME680 with ESP8266 and BSEC 1.4.704 library. Sensor interfacing code is based on “basic_config_state.ino” example. Sensor works in LP mode (data updates every 3 seconds) with periodical state saves to SPIFFS. BSEC data subscriptions: BSEC_OUTPUT_RAW_TEMPERATURE,
BSEC_OUTPUT_RAW_PRESSURE,
BSEC_OUTPUT_RAW_HUMIDITY,
BSEC_OUTPUT_RAW_GAS,
BSEC_OUTPUT_IAQ,
BSEC_OUTPUT_STATIC_IAQ,
BSEC_OUTPUT_GAS_PERCENTAGE,
BSEC_OUTPUT_CO2_EQUIVALENT,
BSEC_OUTPUT_BREATH_VOC_EQUIVALENT,
BSEC_OUTPUT_SENSOR_HEAT_COMPENSATED_TEMPERATURE,
BSEC_OUTPUT_SENSOR_HEAT_COMPENSATED_HUMIDITY This configuration is working more than one week, six sensors are placed together. After some time being powered on (about 3 days) devices output similar IAQ values from all sensors, so here we will analyze one sensor data. We compared BME680 BSEC library output values with another tVOC sensor (SGX) values (this sensor is providing values directly) and we observing strange behavior. On pictures you can see one day comparison and ~3.5 days comparison. Explanation of images: BME680 – orange. SGX – green (other sensor is red and blue). There are one day comparison in one image, and ~3.5 days comparison in other two images (please note, that SGX data not from same sensor, so it is not equal, but very close). These “rectangular peaks” are at night, when room active ventilation is off. We need some help with these things: Why so fast rising of IAQ and CO2 to peak value after ventilation gets off, but after while level is decreasing slowly until ventilation gets on? SGX sensor output values looks more real (maybe similar to exponential). Why sometimes we observe CO2 about 2000ppm (and in older tests, which are not presented here, we got almost 3000ppm) at same time when SGX sensor shows less than 1000ppm? What is the best choice of data to control the room ventilation? IAQstatic? Thanks, Alexander One day BME680/SGX Three days BME680 Three days SGX
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