BME688 evaluation

[Minhwan]

Hi, 

I checked your log, it's quite strange result. 

Several questions I have. 

1. Have you changed any code for BME68x API? If yes, please don't. Just modify BSEC source code is enough. 

2. Which config file are you using it? If you are using config file which we provided, 5 cyclic result doesn't make sense. Are you using custom config file made yourself? Could you upload it config file? 

Thanks, 

[doppio-R]

Hi,

I haven't changed any code in the API. The file, which I have uploaded is the only one. Many parts of the code are from Bosch as well. The config file belongs to an older bsec 2.X version. The array has the size of 2277 and is the bsec_sel_iaq_33v_3s_28d.

In your datasheet is written, that the sensor has 5 measurement cycles during the gas sensor mode.

[Minhwan]

Hi doppio, 

Yes, I'm talking about the code you uploaded. 

It seems like you mixed BME68x API example code and BSEC example code. 

For exampe, you don't need those kind of code for getting proper data. 

  uint16_t temp_prof[10] = { 250, 100, 100, 100, 100, 100, 100, 250, 250, 250 };		// Heater temperature in degree Celsius
  uint16_t mul_prof[10] = { 2, 0, 10, 15, 2, 2, 2, 2, 2, 2 };							// Multiplier to the shared heater duration

There is latest BSEC2 in below url

https://www.bosch-sensortec.com/software-tools/software/bme688-software/

And there is integration guide in the bsec2 library zip file. 

Please download and check the integration guide. 

And feel free to ask me after you check the document. 

Plus, in case of scan mode, you can make your own scan mode technically, but BSEC2 handles it. 

Thank you. 

[doppio-R]

Hi Minhwan,

i downloaded the new software and renew my code. See below. I changed the power mode to LP, because I'm interested in the air quality and do not search for a specific gas. Additional I updated the associated files. When I'm using the newer libalgobsec.a the system seems more agile and realistic, but the CO2 value starts at 600 and do not go below. Why?   Even though I'm sitting next to an open window, I don't get the low value.

Additional the values of temperature and humidity in both library version have a big difference. Which version should I use?

I attach the log file, where both versions are included. During both measurement I have blow to the sensor.

Thanks.

[Minhwan]

Hi, 

I saw your result and it is pretty much okay so far. 

You can get any CO2 value once you reach to IAQ accuracy level 1  although we recommend to wait up to 3. 

Then, CO2 value changed in your log down to 460 when IAQ is going down, then CO2 level going up when IAQ level is going up. 

And I recommend to use latest BSEC library and recommend to keep checking data for a long time. 

Thanks,