Some of the questions about Asset Tracker

RE: Some of the questions about Asset Tracker

Martin Lesund — Fri, 31 Jul 2020 12:56:47 GMT

Hi Xinjiang,

(Please note the BME680 sensor, like all VOC/gas sensors, has variability and to get precise measurements you will want to calibrate it against known sources! That said, for general environmental sensors, it will give you a good idea of trends and comparisons. We recommend that you run this sensor for 48 hours when you first receive it to "burn it in", and then 30 minutes in the desired mode every time the sensor is in use. This is because the sensitivity levels of the sensor will change during early use, and the resistance will slowly rise over time as the MOX warms up to its baseline reading.)

2.
Good to hear that you made it work out.

RE: Some of the questions about Asset Tracker

xinjiang — Fri, 31 Jul 2020 02:48:06 GMT

1、The code in this website also does not initialize the air quality test. I tried to turn this on myself.

+static struct env_sensor quality_sensor = {
+	.sensor =  {
+		.type = ENV_SENSOR_AIR_QUALITY,
+		.value = 0,
+	},
+	.channel = SENSOR_CHAN_GAS_RES,
+	.dev_name = CONFIG_TEMP_DEV_NAME
+};

/* Array containg environment sensors available on the board. */
static struct env_sensor *env_sensors[] = {
	&temp_sensor,
	&humid_sensor,
	&pressure_sensor,
+   &quality_sensor
};

int env_sensors_get_air_quality(env_sensor_data_t *sensor_data)
{
+	if (sensor_data == NULL) {
+		return -1;
+	}
+	k_spinlock_key_t key = k_spin_lock(&quality_sensor.lock);
+
+	memcpy(sensor_data, &(quality_sensor.sensor),
+		sizeof(quality_sensor.sensor));
+	k_spin_unlock(&quality_sensor.lock, key);
+	return 0;
//        return -1;
}

I get the following data. I don't know what this means. What are the units of this data?

{"appId":"AIR_QUAL","data":"74625","messageType":"DATA"}
{"appId":"AIR_QUAL","data":"81131","messageType":"DATA"}
{"appId":"AIR_QUAL","data":"10675","messageType":"DATA"}
{"appId":"AIR_QUAL","data":"10213","messageType":"DATA"}

2、According to the nrf_cloud_apgs routine, I turned on the GPS three seconds after sending the A-GPS request and successfully received the A-GPS data.

Best regards,

Xinjiang

RE: Some of the questions about Asset Tracker

Martin Lesund — Thu, 30 Jul 2020 13:27:26 GMT

Hi Xinjiang,

1.
It is because you need to run the BSEC library, so just use that instead --> https://github.com/nrfconnect/sdk-nrf/blob/master/applications/asset_tracker/src/env_sensors/env_sensors.c#L196

2.
Could you share the full log over a longer period of time?

Also make sure you are using the latest mfw: https://www.nordicsemi.com/Products/Low-power-cellular-IoT/nRF9160/Download#infotabs

(you can try to send the A-GPS request before the GPS turns ON, and then give a delay around 5-10 seconds to respond before GPS (including PSM) turns ON).

One quick test you can do is to set CONFIG_GPS_CONTROL_PSM_ENABLE_ON_START=n in prj.conf, to see if it is some issues with PSM.
(which SIM card are you using?)