bsec_bme680_linux

Read the BME680 sensor with the BSEC library on Linux (e.g. Raspberry Pi)

Intro

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.

Prerequisites

Download the BSEC software package from Bosch and put it into ./src, then unpack.

Configure and Compile

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

Usage

Output will be similar to this:

$ ./bsec_bme680
2017-12-27 18:47:21,[IAQ (1)]: 33.96,[T degC]: 19.61,[H %rH]: 46.41,[P hPa]: 983.39,[G Ohms]: 540924.00,[S]: 0
2017-12-27 18:47:24,[IAQ (1)]: 45.88,[T degC]: 19.61,[H %rH]: 46.41,[P hPa]: 983.41,[G Ohms]: 535321.00,[S]: 0
2017-12-27 18:47:26,[IAQ (1)]: 40.65,[T degC]: 19.60,[H %rH]: 46.45,[P hPa]: 983.39,[G Ohms]: 537893.00,[S]: 0
2017-12-27 18:47:29,[IAQ (1)]: 30.97,[T degC]: 19.60,[H %rH]: 46.42,[P hPa]: 983.41,[G Ohms]: 542672.00,[S]: 0

• IAQ (n) - Accuracy of the IAQ score from 0 (low) to 3 (high).
• S: n - Return value of the BSEC library

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.

Further

You can find a growing list of tools to further use and visualize the data here.

Troubleshooting

Raspberry Pi

Make sure you enabled I2C functionality first.

bsec_bme680 just quits without a message

Your bsec_iaq.state file might be corrupt or incompatible after an update of the BSEC library. Try (re)moving it.

remote I/O error

If you get user_i2c_write: Remote I/O error on run time, check the I2C address used by your version of the sensor:

sudo i2cdetect -y 1

If you find a device on 77 but not on 76, then your sensor is configured to use its secondary I2C address. In this case, change this at the beginning of bsec_bme680.c:

int i2c_address = BME680_I2C_ADDR_PRIMARY;

to

int i2c_address = BME680_I2C_ADDR_SECONDARY;

and recompile (./make.sh).