BME688: Heater profile theory of operation?

[gdm528]

I'm looking for a detailed explanation on the temperature and duration effects of the sensor heater in the BME688.  I can adjust the heater temperature over a very wide range, and likewise with the duration of the applied heat - that's awesome, but now what?

Why set the heater temperature higher or lower, how does that change the sensor's response to gasses?

Why set the heater duration longer or shorter, how does that change the sensor's response to gasses?

I'm aware of the AI Studio.  While it may provide the optimum settings, it doesn't explain why those settings were optimal.  I'm looking for guidance on heuristic methods to dial in and/or modify the heater profile settings.  Actual recommended settings for various gasses would be super-helpful.

[BSTRobin]

Hi gdm528，

Normally, for temperature, it's better to set from 200 to 400, and for duration, it's better from 30 to 4032ms.
What type of gas do you want to detect?

[gdm528]

BSTRobin,

Thanks for responding!

I'm aware of the recomended temperature and duration settings, but I don't know why they are what they are.  I've already experimentally determined that I can't just randomly choose a value within the recomended ranges - big difference between 200C and 400C.  Why did changing the temperature change the response?  

I've found a few university papers that discuss MOX sensor experiments, but my research is duplicating the labor that's already been spent by other users.  I'd rather not have to repeat the journey Bosch took to understand and characterize the BME688.  It would be a magic moment in customer service for Bosch to share their data with their customers - who also happen to be engineers.  Is there a whitepaper, journal article, etc.?

My question is general in nature, so I'll address the specifics of my application in another post.

[BSTRobin]

Hi gdm528，

Based on testing experience in gas detection, it is recommended to use a reference heater temperature and duration. If you do not want to use the reference heater duration and temperature, of course, you can also test the reaction of the gas and use your own experience values.