11-28-2019 03:45 PM
Hi,
I have an application where the BME680 will be in close proximity to a users mouth many hours a day. 1) Will the gas and VOC and IAQ readings still be accurate in this use case. 2) Will the high humidity over time degrade the device?
Thank you!
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11-28-2019 05:44 PM
@kevyk wrote:
Will the high humidity over time degrade the device?
We typically don't expect the humidity level itself to damage the sensor, but what should be avoided are condensation from forming inside/outside of the sensor's package, as well as any potential liquids/particulates from reaching the sensor (e.g. using a protective membrane). Note that we expect that you run your own qualification tests to validate your use-case.
@kevyk wrote:
Will the gas and VOC and IAQ readings still be accurate in this use case.
The gas sensor's outputs will still be accurate, but you will need to design your HW (e.g. are you looking for VOCs from the mouth itself, from the surrounding environment, ...) as well as consider the appropriate BSEC outputs (e.g. IAQ, sIAQ, a customized one, ...) based on your specific use-case requirements. For instance we could expect higher VOC concentrations near a user's mouth than in the surrounding environment, so based on the design this could be observed in the output.
12-02-2019 06:45 PM
Thanks handytech. Yes we would run our own qualification tests. This would be probably 1-2 inches away from the users mouth in an enclosed environment so humidity could be high.
I don't know if condensation would be present though. If it is present, are there membranes that could be used in front of the gas sensor to mitigate the condensation but still let in all pertinent gasses for measurement?
As far as data output from the sensor, it provides various output data, correct? Plus using the IAQ algorithm gives an overall level of VOC's, correct?
Thank you!
12-03-2019 06:15 PM
@kevyk wrote:
I don't know if condensation would be present though. If it is present, are there membranes that could be used in front of the gas sensor to mitigate the condensation but still let in all pertinent gasses for measurement?
Membranes (such as PTFE vents) can be used to prevent direct liquid/dust from reaching the sensor, while allowing pertinent gases (but also pressure, humidity, etc.) measurements. On the other hand, a membrane cannot prevent condensation from forming within the device/cavity directly, so this risk and potential conditions have to be evaluated for you application. For a better understanding of these membranes and their integration, please get in touch with your preferred supplier (e.g. GORE, etc.).
@kevyk wrote:
As far as data output from the sensor, it provides various output data, correct? Plus using the IAQ algorithm gives an overall level of VOC's, correct?
BME680's gas sensor will report a raw resistance value (in Ω). Feeding this raw sensor value (together with raw temperature/pressure/humidity) to our BSEC library will allow you to benefit from our advanced outputs like IAQ, etc.