Adafruit offers a simple breakout board featuring the long awaited BME680 from Bosch Sensortec which provides multiple environmental sensors in one small package. This little sensor contains temperature, humidity, barometric pressure, and volatile organic compounds (VOC) gas sensing capabilities, and all over SPI or I²C.

Like the BME280 and BMP280, this precision sensor from Bosch can measure humidity with ±3% accuracy, barometric pressure with ±1 hPa absolute accuracy, and temperature with ±1.0°C accuracy. Because pressure changes with altitude and the pressure measurements are so accurate, it can also be used as an altimeter with ±1 meter or better accuracy.

The BME680 takes those sensors to the next step in that it contains a small MOX sensor. The heated metal oxide changes resistance based on the VOCs in the air so it can be used to detect gasses and alcohols such as ethanol, alcohol and carbon monoxide, and perform air quality measurements. Note: It gives one resistance value with overall VOC content, but it cannot differentiate gasses or alcohols.

Adafruit recommends that this sensor is ran for 48 hours when it is first received 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.

For convenience Adafruit has picked-and-placed the sensor on a PCB with a 3.3 V regulator and level shifting, so it can be easily used with a 3.3 V or 5 V microcontroller.