BSEC BME680 no IAQ output

[MJ_kio]

This is my fucntion process data

    /* Check if something should be processed by BSEC */
    if (num_bsec_inputs > 0) {
        /* Set number of outputs to the size of the allocated buffer */
        /* BSEC_NUMBER_OUTPUTS to be defined */
        num_bsec_outputs = BSEC_NUMBER_OUTPUTS;

        /* Perform processing of the data by BSEC
           Note:
           * The number of outputs you get depends on what you asked for during bsec_update_subscription(). This is
             handled under bme680_bsec_update_subscription() function in this example file.
           * The number of actual outputs that are returned is written to num_bsec_outputs. */
        bsec_status = bsec_do_steps(bsec_inputs, num_bsec_inputs, bsec_outputs, &num_bsec_outputs);
        if (bsec_status != BME680_OK) return bsec_status;

        KD_DEBUG(KD_BME680_BSEC, "num_bsec_outputs %d", num_bsec_outputs);

        /* Iterate through the outputs and extract the relevant ones. */
        for (index = 0; index < num_bsec_outputs; index++) {
            switch (bsec_outputs[index].sensor_id) {
                case BSEC_OUTPUT_IAQ:
                    KD_DEBUG(KD_BME680_BSEC, "BSEC_OUTPUT_IAQ");
                    iaq = bsec_outputs[index].signal;
                    iaq_accuracy = bsec_outputs[index].accuracy;
                    break;
                case BSEC_OUTPUT_STATIC_IAQ:
                    KD_DEBUG(KD_BME680_BSEC, "BSEC_OUTPUT_STATIC_IAQ");
                    static_iaq = bsec_outputs[index].signal;
                    static_iaq_accuracy = bsec_outputs[index].accuracy;
                    break;
                case BSEC_OUTPUT_CO2_EQUIVALENT:
                    KD_DEBUG(KD_BME680_BSEC, "BSEC_OUTPUT_CO2_EQUIVALENT");
                    co2_equivalent = bsec_outputs[index].signal;
                    co2_accuracy = bsec_outputs[index].accuracy;
                    break;
                case BSEC_OUTPUT_BREATH_VOC_EQUIVALENT:
                    KD_DEBUG(KD_BME680_BSEC, "BSEC_OUTPUT_BREATH_VOC_EQUIVALENT");
                    breath_voc_equivalent = bsec_outputs[index].signal;
                    breath_voc_accuracy = bsec_outputs[index].accuracy;
                    break;
                case BSEC_OUTPUT_SENSOR_HEAT_COMPENSATED_TEMPERATURE:
                    KD_DEBUG(KD_BME680_BSEC, "BSEC_OUTPUT_SENSOR_HEAT_COMPENSATED_TEMPERATURE");
                    temp = bsec_outputs[index].signal;
                    break;
                case BSEC_OUTPUT_RAW_PRESSURE:
                    KD_DEBUG(KD_BME680_BSEC, "BSEC_OUTPUT_RAW_PRESSURE");
                    raw_pressure = bsec_outputs[index].signal;
                    break;
                case BSEC_OUTPUT_SENSOR_HEAT_COMPENSATED_HUMIDITY:
                    KD_DEBUG(KD_BME680_BSEC, "BSEC_OUTPUT_SENSOR_HEAT_COMPENSATED_HUMIDITY");
                    humidity = bsec_outputs[index].signal;
                    break;
                case BSEC_OUTPUT_RAW_GAS:
                    KD_DEBUG(KD_BME680_BSEC, "BSEC_OUTPUT_RAW_GAS");
                    raw_gas = bsec_outputs[index].signal;
                    break;
                case BSEC_OUTPUT_RAW_TEMPERATURE:
                    KD_DEBUG(KD_BME680_BSEC, "BSEC_OUTPUT_RAW_TEMPERATURE");
                    raw_temp = bsec_outputs[index].signal;
                    break;
                case BSEC_OUTPUT_RAW_HUMIDITY:
                    KD_DEBUG(KD_BME680_BSEC, "BSEC_OUTPUT_RAW_HUMIDITY");
                    raw_humidity = bsec_outputs[index].signal;
                    break;
                case BSEC_OUTPUT_COMPENSATED_GAS:
                    KD_DEBUG(KD_BME680_BSEC, "BSEC_OUTPUT_COMPENSATED_GAS");
                    comp_gas_value = bsec_outputs[index].signal;
                    comp_gas_accuracy = bsec_outputs[index].accuracy;
                    break;
                case BSEC_OUTPUT_GAS_PERCENTAGE:
                    KD_DEBUG(KD_BME680_BSEC, "BSEC_OUTPUT_GAS_PERCENTAGE");
                    gas_percentage = bsec_outputs[index].signal;
                    gas_percentage_acccuracy = bsec_outputs[index].accuracy;
                    break;
                default:
                    continue;
            }

            /* Assume that all the returned timestamps are the same */
            timestamp = bsec_outputs[index].time_stamp;
        }

[MJ_kio]

Hi @BSTRobin ,

This sentence is very interesting sentence : We found such as "case BSEC_OUTPUT_IAQ" .etc didn't run to assign iaq lead to IAQ output is 0 in the log.

Could you write to me something more regarding this issue? What was its cause and how it was solved?

[MJ_kio]

Hi @BSTRobin 

Could you answer my questions above?
Moreovere what are required compilation flags for bsec library?
I am strunggling with constant timestamp from bsec output (01015539:D:KD_BME680_BSEC :Timestamp: 16000000) and no IAQ.
Could you support? We want to release large product series with BME680, however it is a blocker for us now.

[MJ_kio]

Hi @BSTRobin 

I think I found root cause of showing IAQ 0, despite fact received timestamp is constant. I applied config `generic_33v_3s_4d` and I needed to commented out two `if` statements in file `bsec_integration.c` in function `bme680_bsec_read_data` (I don't think it's proper solution, does it?):

            /*
             * Following if statements have to be fixed, this is a root cause
             */

            /* Gas to be processed by BSEC */
            // if (bsec_process_data & BSEC_PROCESS_GAS) {
            /* Check whether gas_valid flag is set */
            // if (data.status & BME680_GASM_VALID_MSK) {
            /* Place sample into input struct */
            inputs[*num_bsec_inputs].sensor_id = BSEC_INPUT_GASRESISTOR;
            inputs[*num_bsec_inputs].signal = (float)data.gas_resistance;
            inputs[*num_bsec_inputs].time_stamp = time_stamp_trigger;
            (*num_bsec_inputs)++;
            //}
            // }

IAQ was 0, because algorithm never receives gas resistance. Both flags are not set. When I commented behaviour is the same as in Arduino example (despite constant output timestamp in comparison to Arduino example).

Going up `bsec_process_data` comes from `bme680_bsec_trigger_measurement` and `bsec_sensor_control`.
I don't see where flag `BSEC_PROCESS_GAS` is set, could you point me where is it or how to use it? When is it set?

Flag `BME680_GASM_VALID_MSK`comes directly from sensor. Why it is not set? How to set it properly?

What I have to do to run whole framework successfuly?

[BSTRobin · Accepted solution]

Hi MJ_kio,

Please check our previous replies, because output order in function 'bme68x_bsec_process_data' is different from in log.
About the new feedback, i find the two flags ing bsec_iot_example.ino:
in ''bsec_datatypes.h"----- '#define BSEC_PROCESS_GAS (1 << (BSEC_INPUT_GASRESISTOR-1))' 'BSEC_INPUT_GASRESISTOR = 4, '
in "bme68x_defs.h"--------'#define BME68X_GASM_VALID_MSK UINT8_C(0x20)'
If you think the IAQ output is 0 due to these two 'if' statements are not executed, you can print some message in it by adding logs.
Or can you change a new 680 senser to test?