Bosch Sensortec recently announced a new environmental sensor, the BME680. It actually builds on prior devices. The first was simply pressure and temperature; the next added humidity; and the BME680 adds gas sensing to that.
We’ve looked at a variety of ways to do analyte detection in the past, so I was curious as to which of those Bosch used in this device.
And the answer is: none of the above.
The humidity is detected by a polymer that adsorbs water and affects a capacitance; then again, that’s not what’s new in this device.
The gas sensing is not as specific as what we’ve looked at. It’s a single membrane onto which a number of different analytes can adsorb. I wasn’t able to get much more detail than that; in general, they detect volatile organic compounds (VOCs) and alcohol. It’s a consumer-friendly sensor that doesn’t give specific numbers for specific gasses; it simply says whether or not there’s an issue with the air. It’s driven by the indoor air quality (IAQ) guidelines that regulatory bodies issue.
So while it may not be as selective or specific as what some of the other techniques provide, it is targeted at mobile devices, so size (3-mm square) and low power are key deliverables. And, realistically, it’s unlikely that most phone users would do much with specific analyte numbers anyway.
You can get more detail from their announcement.
(Image courtesy Bosch Sensortec.)