Read the BME680 sensor with the BSEC library on Linux (e.g. Raspberry Pi)
Working example of fully using the BME680 sensor on Linux (e.g. Raspberry Pi) with the precompiled BSEC library, which allows to read calibrated environment values including an actual Indoor Air Quality (IAQ) score.
It makes use of Bosch's provided driver and can be configured in terms of it. Readings will be directly output to stdout in a loop.
Download the BSEC software package from Bosch
and put it into ./src, then unpack.
Example :
cd ./src
wget https://www.bosch-sensortec.com/media/boschsensortec/downloads/bsec/bsec_1-4-8-0_generic_release.zip
unzip bsec_1-4-8-0_generic_release.zip
rm bsec_1-4-8-0_generic_release.zip
cd bsec_1-4-8-0_generic_release
wget https://github.com/BoschSensortec/BME680_driver/archive/bme680_v3.5.10.zip
mv BME680_driver-bme680_v3.5.10/ API
Optionally make changes to make.config.
Depending on how your sensor is embedded it might be surrounded by other
components giving off heat. Use an offset in °C in bsec_bme680.c to
compensate. The default is 5 °C:
#define temp_offset (5.0f)
To compile: ./make.sh
Output will be similar to this:
$ ./bsec_bme680
{"Localtime": "2020-11-14 22:55:43","IAQ_Accuracy": "3","IAQ":"245.41","Temperature": "15.30","Humidity": "84.98","Pressure": "1007.15","Gas": "33587","Status": "0","eCO2": "2652.58","bVOCe": "18.89"}
{"Localtime": "2020-11-14 22:55:46","IAQ_Accuracy": "3","IAQ":"245.10","Temperature": "15.29","Humidity": "85.01","Pressure": "1007.13","Gas": "33534","Status": "0","eCO2": "2649.13","bVOCe": "18.79"}
{"Localtime": "2020-11-14 22:55:49","IAQ_Accuracy": "3","IAQ":"244.77","Temperature": "15.29","Humidity": "85.03","Pressure": "1007.13","Gas": "33560","Status": "0","eCO2": "2645.51","bVOCe": "18.69"}
- Localtime - Local system time
- IAQ_Accuracy - Accuracy of the IAQ score from 0 (low) to 3 (high).
- IAQ - IAQ score (0-50 good || 51-100 average || 101-150 little bad || 151-200 bad || 201 –300 worse || 301 –500 very bad)
- Temperature - Temperature value in Celsius
- Humidity - Humidity value in percent
- Pressure - Pressure value in hPa
- Gas - Gas value in Ohms
- Status - status of the sensors
- eCO2 - eCO2 value in ppm
- bVOCe - bVOCe value in ppm
It can easily be modified in the output_ready function.
The BSEC library is supposed to create an internal state of calibration with
increasing accuracy over time. Each 10.000 samples it will save the internal
calibration state to ./bsec_iaq.state (or wherever you specify the config
directory to be) so it can pick up where it was after interruption.
The output of the sensor can easily be sent to MQTT using Mosquitto
First, install Mosquitto Client sudo apt-get install mosquitto-clients
Launch the program and send the standard output to your Mosquitto broker
./bsec_bme680 | mosquitto_pub -h 192.168.1.XXX -u "your broker user" -P "your broker password" -p 1883 -t home/pizero/bme680 -l
This can be automated launching run.sh using systemd unit file, with the below command
sudo useradd -r -G i2c -s /usr/sbin/nologin sensors
sudo mkdir /opt/bsec_bme680/
sudo cp ./bsec_bme680 /opt/bsec_bme680/
sudo cp bsec_bme680.logrotate /etc/logrotate.d/bsec_bme680
sudo cp run.sh /opt/bsec_bme680/
sudo cp bsec_bme680.service /lib/systemd/system/
sudo chown -R sensors:i2c /opt/bsec_bme680/
sudo chmod 744 /opt/bsec_bme680/run.sh
sudo touch /var/log/bsec_bme680.log
sudo chown sensors:i2c /var/log/bsec_bme680.log
sudo systemctl daemon-reload
sudo systemctl start bsec_bme680.service
systemctl status bsec_bme680.service
sudo systemctl enable bsec_bme680.service
You can find a growing list of tools to further use and visualize the data here.
Your bsec_iaq.state file might be corrupt or incompatible after an update of the BSEC library. Try (re)moving it.