Choosing heater profiles

[zrummler]

We're looking to use the bme68x sensor to detect different gases such as coffee, smoke, fresh air, etc. So, we're looking for the right gas heater profile(s) to use, and we don't have much intuition on how to come up with them on our own. Any tips or resources on choosing heater profiles?

Is the default heater profile from the datasheet the best place to start? If that doesn't work, what do you recommend next?

Is it also recommended to use multiple heater profiels for detecting different gases? Or is there a one-size-fits-all?

[BSTRobin]

Hi zrummler,

We have not compared the selection of different heating profile.
BME AI Studio supports up to 4 heating profiles in its board configuration.

[zrummler]

I'm using the sensor API (bme68x.h) and wondering how can I access the standard heater profile? The starter code has:

uint16_t temp_prof[PROFILE_LEN] = { 320, 100, 100, 100, 200, 200, 200, 320, 320, 320 };
uint16_t mul_prof[PROFILE_LEN] = { 5, 2, 10, 30, 5, 5, 5, 5, 5, 5 };

but this is not the standard heater profile, as the durations here are much shorter (the profile lasts 87 milliseconds, but the standard heater profile above lasts 10+ seconds).

My questions are:

1. Is there a way to access the standard heater profile which is built-in to the chip's ASIC, according to the datasheet?

2. Does it even matter to use the standard, 10 second heater profile vs. the shortened, 87ms version listed above?

[BSTRobin]

Hi gdm528，

We recommend that you use a standard heater profile, as shown in BME AI Studio:

If you want to use a custom heater profile, based on our experience, for temperature, it's better to set from 200 to 400, and for duration, it's better from 30 to 4032ms. Refer to document https://www.bosch-sensortec.com/media/boschsensortec/downloads/application_notes_1/bst-bme688-an001.... to set temperature and duration of heater profile.