BME688 - Gas/Temperature/Humidity/Pressure sensor, I2C / SPI, Qwiic / StemmaQT
BME688 breakout
- Temperature
- Humidity
- Athmospheric pressure
- VoC Gas (CO)
- Interface: SPI or I2C
- Connector Qwiic / StemmaQT
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Environmental sensor BME688 including gas analysis (MoX sensor)
The BME688 from Bosch is the ultimate all the environmental sensor fitted into a small package.
This little sensor can measure:
- temperature,
- humidity,
- barometric pressure,
- VoC gas.
All over SPI or I2C at a great price!
The BME688 is the drop replacement of the famous BME680. Compare to the BME680, it adds a programming instruction to control the gas-sensor heater. The BME688 allows to control air quality (odor-analysis) but otherwise it is the same hardware as BME680. Check out this video for details about using some machine-learning for using the BME688 as odor detection.
The precision of the sensor is the same as BME280 and BMP280:
- +/-3% accuracy for humidity,
- +/-1 hPa absolute accuracy for barometric pressure,
- +/- 1.0°C accuracy for temperature.
Because pressure changes with altitude this sensor can also be use as an altimeter. Thanks to the barometric sensor accuracy you can reach +/- 1 meter accuracy!
The BME688 contains a small MOX sensor (heated metal oxide) which have a changing resistance based on the volatile organic compounds (VOC) in the air. The BME688 can be used to detect gasses and alcohols compounds like Ethanol, Alcohol as well as Carbon Monoxide. This sensor can be used to perform air quality measurements. Please note that MoX sensor will provides one resistance value compiling the overall VOC content (not difference between gaz and alcohols).
The BME688 is fitted onto a breakout PCB with 3.3V regulator and level shifting, so you can use it with any 3.3V or 5V microcontroller. All of the BME688 signals are breakout on the 2.54mm connector (to use it on a breadboard). The board also fits Qwiic / StemmaQt connectors transporting power and I2C bus. Such connector is great to make quick connexion with microcontroller already having such connectivity (otherwise you can also use a JST-SH 4 cable adapter to ease the wiring and avoids soldering). It is possible to find several StemmaQT/Qwiic/JST-SH4 cable on our shop.
Technical details
- 3.3V and 5V ready
- Interface: I2C
- Size: 25.5mm x 17.6mm x 4.6mm
- Weight: 1.7g
- BME688 datasheet (pdf)
Content
For each order, you will receive a BME688 board completely assembled and tested. The breakout is shipped with a pinHeader connection (male connector).
Variability and calibration
N Please note this sensor, like all VOC/gas sensors, has variability, and to get precise measurements you will want to calibrate it against known sources! That said, for general environmental sensors, it will give you a good idea of trends and comparisons.
It is recommended to run this sensor for 48 hours when you first receive it to "burn it in", and then 30 minutes in the desired mode every time the sensor is in use. This is because the sensitivity levels of the sensor will change during early use, and the resistance will slowly rise over time as the MOX warms up to its baseline reading.
Tutorial
- Using the BME68x (Adafruit, English)
Arduino and CircuitPython tutorial for Temperature, Humidity, Pressure and gas detection!