Hi,
I am working with a BME680 VOC sensor on a project and I have detected some abnormal performance while reading values for a long time.
My setup is as follows:
- BSEC 1.4.8.0 Normal Version
- generic_18v_300s_4d config operation
- I have a sensor calibrated as indicated in the manual: about 30 minutes exposed to fresh air and another 30 minutes in a box with exhaled breath. During this calibration process I was able to see how the IAQ accuray went from index 0 to index 3.
- Location: Indoor office
After that, I was reading some values that were more or less correlated with measurements taken from other VOC sensors that we were using as a reference. However, at some point in time, BME680 took some wrong value and started a recalibration (index 2) until new calibrated values were obtained.
Here you can find a snapshot of the logs:
[05:23:17.046] T, 24.52, rH, 30.85, Pa, 93866.99, IAQ, 128.94 (3), Static IAQ, 110.07, CO2e, 1100.71 (3), bVOC, 1.80 (3)
[05:23:20.052] T, 24.51, rH, 30.93, Pa, 93863.14, IAQ, 129.27 (3), Static IAQ, 110.33, CO2e, 1103.35 (3), bVOC, 1.81 (3)
[05:23:23.058] T, 24.52, rH, 30.90, Pa, 93866.49, IAQ, 128.77 (3), Static IAQ, 109.92, CO2e, 1099.20 (3), bVOC, 1.80 (3)
[05:23:26.064] T, 24.52, rH, 30.94, Pa, 93865.57, IAQ, 128.38 (3), Static IAQ, 109.60, CO2e, 1096.01 (3), bVOC, 1.79 (3)
[05:23:29.070] T, 24.52, rH, 30.95, Pa, 93866.09, IAQ, 132.40 (3), Static IAQ, 112.89, CO2e, 1128.92 (3), bVOC, 1.88 (3)
[05:23:32.076] T, 24.51, rH, 30.95, Pa, 93862.64, IAQ, 153.91 (3), Static IAQ, 130.48, CO2e, 1304.86 (3), bVOC, 2.46 (3)
[05:23:35.082] T, 24.52, rH, 30.93, Pa, 93866.60, IAQ, 174.60 (3), Static IAQ, 147.41, CO2e, 1474.13 (3), bVOC, 3.18 (3)
[05:23:38.088] T, 24.52, rH, 30.97, Pa, 93864.11, IAQ, 189.91 (3), Static IAQ, 159.93, CO2e, 1599.35 (3), bVOC, 3.84 (3)
[05:23:41.094] T, 24.52, rH, 30.96, Pa, 93865.80, IAQ, 212.69 (3), Static IAQ, 178.56, CO2e, 1785.64 (3), bVOC, 5.09 (3)
[05:23:44.100] T, 24.52, rH, 30.95, Pa, 93865.80, IAQ, 236.98 (3), Static IAQ, 198.43, CO2e, 1984.37 (3), bVOC, 6.87 (3)
[05:23:47.106] T, 24.52, rH, 30.95, Pa, 93865.85, IAQ, 264.75 (2), Static IAQ, 221.86, CO2e, 2218.62 (2), bVOC, 9.80 (2)
[05:23:50.112] T, 24.52, rH, 30.95, Pa, 93865.07, IAQ, 312.35 (2), Static IAQ, 261.79, CO2e, 2617.94 (2), bVOC, 17.92 (2)
[05:23:53.118] T, 24.52, rH, 30.97, Pa, 93865.98, IAQ, 369.26 (2), Static IAQ, 309.70, CO2e, 3097.06 (2), bVOC, 36.98 (2)
[05:23:56.124] T, 24.53, rH, 30.98, Pa, 93866.55, IAQ, 427.10 (2), Static IAQ, 358.71, CO2e, 3587.18 (2), bVOC, 77.59 (2)
[05:23:59.130] T, 24.52, rH, 31.03, Pa, 93865.92, IAQ, 471.39 (2), Static IAQ, 396.78, CO2e, 3967.88 (2), bVOC, 137.96 (2)
[05:24:02.136] T, 24.53, rH, 31.02, Pa, 93865.97, IAQ, 489.92 (2), Static IAQ, 413.58, CO2e, 4135.87 (2), bVOC, 177.84 (2)
[05:24:05.142] T, 24.52, rH, 30.98, Pa, 93864.74, IAQ, 491.81 (2), Static IAQ, 416.52, CO2e, 4165.27 (2), bVOC, 185.92 (2)
[05:24:29.190] T, 24.53, rH, 30.87, Pa, 93868.17, IAQ, 500.00 (2), Static IAQ, 441.76, CO2e, 4417.66 (2), bVOC, 272.29 (2)
[05:24:32.196] T, 24.54, rH, 30.88, Pa, 93869.30, IAQ, 500.00 (2), Static IAQ, 451.84, CO2e, 4518.46 (2), bVOC, 317.11 (2)
[05:24:35.202] T, 24.53, rH, 30.87, Pa, 93869.53, IAQ, 500.00 (2), Static IAQ, 455.42, CO2e, 4554.22 (2), bVOC, 334.72 (2)
.............
[05:31:02.976] T, 24.54, rH, 30.83, Pa, 93864.33, IAQ, 243.24 (2), Static IAQ, 285.56, CO2e, 2855.62 (2), bVOC, 25.67 (2)
[05:31:05.982] T, 24.55, rH, 30.86, Pa, 93865.46, IAQ, 242.80 (2), Static IAQ, 285.03, CO2e, 2850.32 (2), bVOC, 25.47 (2)
[05:31:08.988] T, 24.55, rH, 30.84, Pa, 93865.01, IAQ, 243.85 (2), Static IAQ, 286.27, CO2e, 2862.78 (2), bVOC, 25.95 (2)
[05:31:11.994] T, 24.55, rH, 30.85, Pa, 93863.44, IAQ, 243.36 (2), Static IAQ, 285.67, CO2e, 2856.76 (2), bVOC, 25.72 (2)
[05:31:15.000] T, 24.55, rH, 30.83, Pa, 93863.95, IAQ, 242.47 (2), Static IAQ, 284.61, CO2e, 2846.14 (2), bVOC, 25.31 (2)
[05:31:18.006] T, 24.55, rH, 30.81, Pa, 93864.39, IAQ, 241.47 (2), Static IAQ, 283.40, CO2e, 2834.03 (2), bVOC, 24.85 (2)
[05:31:21.012] T, 24.55, rH, 30.78, Pa, 93865.75, IAQ, 241.06 (3), Static IAQ, 282.90, CO2e, 2829.09 (3), bVOC, 24.66 (3)
[05:31:24.018] T, 24.55, rH, 30.78, Pa, 93864.90, IAQ, 240.78 (3), Static IAQ, 282.57, CO2e, 2825.71 (3), bVOC, 24.54 (3)
[05:31:27.024] T, 24.55, rH, 30.78, Pa, 93865.99, IAQ, 240.46 (3), Static IAQ, 282.17, CO2e, 2821.70 (3), bVOC, 24.39 (3)
[05:31:30.030] T, 24.55, rH, 30.81, Pa, 93863.61, IAQ, 241.72 (3), Static IAQ, 283.66, CO2e, 2836.67 (3), bVOC, 24.95 (3)
[05:31:33.036] T, 24.55, rH, 30.84, Pa, 93864.17, IAQ, 241.62 (3), Static IAQ, 283.54, CO2e, 2835.40 (3), bVOC, 24.90 (3)
[05:31:36.042] T, 24.55, rH, 30.86, Pa, 93864.39, IAQ, 241.94 (3), Static IAQ, 283.91, CO2e, 2839.14 (3), bVOC, 25.04 (3)
[05:31:39.048] T, 24.55, rH, 30.88, Pa, 93864.28, IAQ, 242.02 (3), Static IAQ, 283.99, CO2e, 2839.94 (3), bVOC, 25.07 (3)
[05:31:42.054] T, 24.55, rH, 30.91, Pa, 93864.06, IAQ, 242.32 (3), Static IAQ, 284.34, CO2e, 2843.48 (3), bVOC, 25.21 (3)
[05:31:45.060] T, 24.56, rH, 30.91, Pa, 93865.12, IAQ, 242.10 (3), Static IAQ, 284.07, CO2e, 2840.73 (3), bVOC, 25.10 (3)
[05:31:48.066] T, 24.55, rH, 30.92, Pa, 93864.23, IAQ, 241.52 (3), Static IAQ, 283.37, CO2e, 2833.76 (3), bVOC, 24.84 (3)
[05:31:51.072] T, 24.56, rH, 30.90, Pa, 93866.09, IAQ, 241.65 (3), Static IAQ, 283.52, CO2e, 2835.21 (3), bVOC, 24.89 (3)
[05:31:54.078] T, 24.56, rH, 30.90, Pa, 93865.29, IAQ, 240.92 (3), Static IAQ, 282.63, CO2e, 2826.39 (3), bVOC, 24.56 (3)
As you can see, we are working in a controlled area with around 1000ppm CO2 values. This concentration values did not change throughout the test (we know this because other VOC sensors gave us CO2 concentration values around 1000ppm throughout the test). However, as you can see, the BME680 started to provide some abnormally high CO2 values (it even hit an IAQ of 500!), began a recalibration, and after that it provided abnormal unrealistically high IAQ, CO2e, and bVOC values.
We don't undertand why the sensor suddenly started showing these strange values. We are planning to use this sensor to monitor Air Quality in critical areas and we can't afford to provide erroneous values.
Have you experienced something like this? Could it be a bug within BSEC library? Do you have any suggestions on what may be going on?
Regards