app: sensor: add fetching data from ccs811 and hm3301

Add support for CCS811 air quality sensor and HM3301 particulate
matter sensor to the fire detection system alongside existing BME280.

Changes:
- Add CCS811 (CO2/VOC) and HM3301 (PM1.0/2.5/10) sensor support
- Configure devicetree overlay for multi-sensor I2C bus setup
- Implement environmental compensation for CCS811 using BME280 data
- Add configurable CCS811_ENV_COMPENSATION with smart threshold updates
- Refactor main.c into modular functions for better maintainability
- Enable required sensor drivers in project configuration

The environmental compensation feature improves CCS811 accuracy by
updating its internal registers with temperature and humidity from
BME280, using a 0.5°C/0.5%RH threshold to minimize I2C traffic.

Refs: #9

Signed-off-by: Natalia Pluta <pluta.natalia.m@gmail.com>

Author: nmpluta

app/Kconfig

@@ -10,6 +10,20 @@ menu "Zephyr"
 source "Kconfig.zephyr"
 endmenu
 
+menu "Application Configuration"
+
+config CCS811_ENV_COMPENSATION
+	bool "Enable environmental compensation for CCS811"
+	default y
+	depends on CCS811 && BME280
+	help
+	  Enable updating CCS811 environmental data register with 
+	  temperature and humidity values from BME280 sensor.
+	  This improves accuracy of CO2 and VOC measurements by
+	  compensating for environmental conditions.
+
+endmenu
+
 module = APP
 module-str = APP
 source "subsys/logging/Kconfig.template.log_config"

app/boards/nrf9160dk_nrf9160.overlay

@@ -25,11 +25,27 @@
 	pinctrl-0 = <&i2c2_default_alt>;
 	pinctrl-1 = <&i2c2_sleep_alt>;
 	pinctrl-names = "default", "sleep";
+	
 	bme280: bme280@77 {
 		compatible = "bosch,bme280";
 		reg = <0x77>;
 		status = "okay";
 	};
+	
+	ccs811: ccs811@5b {
+		compatible = "ams,ccs811";
+		reg = <0x5b>;
+		status = "okay";
+		reset-gpios = <&gpio0 23 GPIO_ACTIVE_LOW>;
+		irq-gpios = <&gpio0 24 GPIO_ACTIVE_LOW>;
+		wake-gpios = <&gpio0 25 GPIO_ACTIVE_LOW>;
+	};
+	
+	hm3301: hm3301@40 {
+		compatible = "seeed,hm330x";
+		reg = <0x40>;
+		status = "okay";
+	};
 };
 
 / {

app/prj.conf

@@ -6,7 +6,10 @@
 CONFIG_LOG=y
 CONFIG_BLINK=y
 
-# Enable I2C and sensor subsystem for BME280
+# Enable I2C and sensor subsystem for multiple sensors
 CONFIG_I2C=y
 CONFIG_SENSOR=y
 CONFIG_BME280=y
+CONFIG_CCS811=y
+CONFIG_CCS811_ENV_COMPENSATION=y
+CONFIG_HM330X=y

app/src/main.c

@@ -5,7 +5,9 @@
 
 #include <zephyr/kernel.h>
 #include <zephyr/drivers/sensor.h>
+#include <zephyr/drivers/i2c.h>
 #include <zephyr/logging/log.h>
+#include <zephyr/drivers/sensor/ccs811.h>
 
 #include <app/drivers/blink.h>
 
@@ -16,60 +18,264 @@ LOG_MODULE_REGISTER(main, CONFIG_APP_LOG_LEVEL);
 #define BLINK_PERIOD_MS_STEP 100U
 #define BLINK_PERIOD_MS_MAX  1000U
 
-int main(void)
-{
-	int ret;
-	const struct device *sensor, *blink;
-	struct sensor_value temp, press, hum;
+/* Function prototypes */
+static int init_sensors(const struct device **bme280, const struct device **ccs811,
+			const struct device **hm3301, const struct device **blink);
+static int read_bme280_data(const struct device *sensor, struct sensor_value *temp,
+			    struct sensor_value *press, struct sensor_value *hum);
+static int read_ccs811_data(const struct device *sensor, struct sensor_value *co2,
+			    struct sensor_value *voc);
+static int read_hm3301_data(const struct device *sensor, struct sensor_value *pm1,
+			    struct sensor_value *pm25, struct sensor_value *pm10);
+static void log_sensor_data(const struct sensor_value *temp, const struct sensor_value *press,
+			    const struct sensor_value *hum, const struct sensor_value *co2,
+			    const struct sensor_value *voc, const struct sensor_value *pm1,
+			    const struct sensor_value *pm25, const struct sensor_value *pm10);
 
-	LOG_INF("Zephyr Fire Detection System %s", APP_VERSION_STRING);
+#ifdef CONFIG_CCS811_ENV_COMPENSATION
+static int update_ccs811_env_data(const struct device *ccs811_sensor,
+				  const struct sensor_value *temp, const struct sensor_value *hum);
+#endif
 
-	sensor = DEVICE_DT_GET(DT_NODELABEL(bme280));
-	if (!device_is_ready(sensor)) {
+static int init_sensors(const struct device **bme280, const struct device **ccs811,
+			const struct device **hm3301, const struct device **blink)
+{
+	/* Initialize BME280 sensor */
+	*bme280 = DEVICE_DT_GET(DT_NODELABEL(bme280));
+	if (!device_is_ready(*bme280)) {
 		LOG_ERR("BME280 sensor not ready");
-		return 0;
+		return -ENODEV;
 	}
 
-	blink = DEVICE_DT_GET(DT_NODELABEL(blink_led));
-	if (!device_is_ready(blink)) {
+	k_sleep(K_MSEC(5000));
+
+	/* Initialize CCS811 sensor */
+	*ccs811 = DEVICE_DT_GET(DT_NODELABEL(ccs811));
+	if (!device_is_ready(*ccs811)) {
+		LOG_ERR("CCS811 sensor not ready");
+		return -ENODEV;
+	}
+
+	/* Initialize HM3301 sensor */
+	*hm3301 = DEVICE_DT_GET(DT_NODELABEL(hm3301));
+	if (!device_is_ready(*hm3301)) {
+		LOG_ERR("HM3301 sensor not ready");
+		return -ENODEV;
+	}
+
+	*blink = DEVICE_DT_GET(DT_NODELABEL(blink_led));
+	if (!device_is_ready(*blink)) {
 		LOG_ERR("Blink LED not ready");
-		return 0;
+		return -ENODEV;
 	}
 
-	ret = blink_off(blink);
+	int ret = blink_off(*blink);
 	if (ret < 0) {
 		LOG_ERR("Could not turn off LED (%d)", ret);
+		return ret;
+	}
+
+	LOG_INF("All sensors initialized successfully");
+	return 0;
+}
+
+static int read_bme280_data(const struct device *sensor, struct sensor_value *temp,
+			    struct sensor_value *press, struct sensor_value *hum)
+{
+	int ret = sensor_sample_fetch(sensor);
+	if (ret < 0) {
+		LOG_ERR("Could not fetch BME280 sample (%d)", ret);
+		return ret;
+	}
+
+	ret = sensor_channel_get(sensor, SENSOR_CHAN_AMBIENT_TEMP, temp);
+	if (ret < 0) {
+		LOG_ERR("Could not get temperature (%d)", ret);
+		return ret;
+	}
+
+	ret = sensor_channel_get(sensor, SENSOR_CHAN_PRESS, press);
+	if (ret < 0) {
+		LOG_ERR("Could not get pressure (%d)", ret);
+		return ret;
+	}
+
+	ret = sensor_channel_get(sensor, SENSOR_CHAN_HUMIDITY, hum);
+	if (ret < 0) {
+		LOG_ERR("Could not get humidity (%d)", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int read_ccs811_data(const struct device *sensor, struct sensor_value *co2,
+			    struct sensor_value *voc)
+{
+	int ret = sensor_sample_fetch(sensor);
+	if (ret < 0) {
+		LOG_ERR("Could not fetch CCS811 sample (%d)", ret);
+		return ret;
+	}
+
+	ret = sensor_channel_get(sensor, SENSOR_CHAN_CO2, co2);
+	if (ret < 0) {
+		LOG_ERR("Could not get CO2 (%d)", ret);
+		return ret;
+	}
+
+	ret = sensor_channel_get(sensor, SENSOR_CHAN_VOC, voc);
+	if (ret < 0) {
+		LOG_ERR("Could not get VOC (%d)", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int read_hm3301_data(const struct device *sensor, struct sensor_value *pm1,
+			    struct sensor_value *pm25, struct sensor_value *pm10)
+{
+	int ret = sensor_sample_fetch(sensor);
+	if (ret < 0) {
+		LOG_ERR("Could not fetch HM3301 sample (%d)", ret);
+		return ret;
+	}
+
+	ret = sensor_channel_get(sensor, SENSOR_CHAN_PM_1_0, pm1);
+	if (ret < 0) {
+		LOG_ERR("Could not get PM1.0 (%d)", ret);
+		return ret;
+	}
+
+	ret = sensor_channel_get(sensor, SENSOR_CHAN_PM_2_5, pm25);
+	if (ret < 0) {
+		LOG_ERR("Could not get PM2.5 (%d)", ret);
+		return ret;
+	}
+
+	ret = sensor_channel_get(sensor, SENSOR_CHAN_PM_10, pm10);
+	if (ret < 0) {
+		LOG_ERR("Could not get PM10 (%d)", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void log_sensor_data(const struct sensor_value *temp, const struct sensor_value *press,
+			    const struct sensor_value *hum, const struct sensor_value *co2,
+			    const struct sensor_value *voc, const struct sensor_value *pm1,
+			    const struct sensor_value *pm25, const struct sensor_value *pm10)
+{
+	LOG_INF("BME280: Temp: %d.%06d C, Press: %d.%06d kPa, Hum: %d.%06d %%", temp->val1,
+		temp->val2, press->val1, press->val2, hum->val1, hum->val2);
+
+	LOG_INF("CCS811: CO2: %d ppm, VOC: %d ppb", co2->val1, voc->val1);
+
+	LOG_INF("HM3301: PM1.0: %d μg/m³, PM2.5: %d μg/m³, PM10: %d μg/m³", pm1->val1, pm25->val1,
+		pm10->val1);
+}
+
+#ifdef CONFIG_CCS811_ENV_COMPENSATION
+static int update_ccs811_env_data(const struct device *ccs811_sensor,
+				  const struct sensor_value *temp, const struct sensor_value *hum)
+{
+	/* Previous environmental values for smart updates */
+	static struct sensor_value prev_temp = {0, 0};
+	static struct sensor_value prev_hum = {0, 0};
+	static bool env_data_initialized = false;
+
+	bool should_update = false;
+
+	/* Check if this is the first update */
+	if (!env_data_initialized) {
+		should_update = true;
+		env_data_initialized = true;
+		LOG_INF("Initializing CCS811 environmental data");
+	} else {
+		/* Check for significant changes (0.5°C or 0.5% RH threshold) */
+		int32_t temp_diff = abs((temp->val1 * 1000000 + temp->val2) -
+					(prev_temp.val1 * 1000000 + prev_temp.val2));
+		int32_t hum_diff = abs((hum->val1 * 1000000 + hum->val2) -
+				       (prev_hum.val1 * 1000000 + prev_hum.val2));
+
+		/* Update if temperature changed by more than 0.5°C or humidity by more than 0.5% */
+		if (temp_diff >= 500000 || hum_diff >= 500000) {
+			should_update = true;
+			LOG_DBG("Environmental change detected - updating CCS811");
+		}
+	}
+
+	if (should_update) {
+		int ret = ccs811_envdata_update(ccs811_sensor, temp, hum);
+		if (ret < 0) {
+			LOG_ERR("Could not update CCS811 environmental data (%d)", ret);
+			return ret;
+		}
+
+		LOG_INF("CCS811 env data updated: T=%d.%02d°C, H=%d.%02d%%", temp->val1,
+			temp->val2 / 10000, hum->val1, hum->val2 / 10000);
+
+		/* Store current values for next comparison */
+		prev_temp = *temp;
+		prev_hum = *hum;
+	}
+
+	return 0;
+}
+#endif /* CONFIG_CCS811_ENV_COMPENSATION */
+
+int main(void)
+{
+	int ret;
+	const struct device *bme280_sensor, *ccs811_sensor, *hm3301_sensor, *blink;
+	struct sensor_value temp, press, hum, co2, voc, pm1, pm25, pm10;
+
+	LOG_INF("Zephyr Fire Detection System %s", APP_VERSION_STRING);
+
+	/* Get I2C device for scanning */
+	const struct device *i2c_dev = DEVICE_DT_GET(DT_NODELABEL(i2c2));
+	if (!device_is_ready(i2c_dev)) {
+		LOG_ERR("I2C device not ready");
+		return 0;
+	}
+
+	/* Initialize all sensors */
+	ret = init_sensors(&bme280_sensor, &ccs811_sensor, &hm3301_sensor, &blink);
+	if (ret < 0) {
+		LOG_ERR("Sensor initialization failed");
 		return 0;
 	}
 
 	while (1) {
-		ret = sensor_sample_fetch(sensor);
+		/* Read BME280 data (temperature, pressure, humidity) */
+		ret = read_bme280_data(bme280_sensor, &temp, &press, &hum);
 		if (ret < 0) {
-			LOG_ERR("Could not fetch BME280 sample (%d)", ret);
-			k_sleep(K_MSEC(1000));
-			continue;
+			LOG_ERR("Failed to read BME280 data");
 		}
 
-		ret = sensor_channel_get(sensor, SENSOR_CHAN_AMBIENT_TEMP, &temp);
-		if (ret < 0) {
-			LOG_ERR("Could not get temperature (%d)", ret);
-			continue;
+#ifdef CONFIG_CCS811_ENV_COMPENSATION
+		/* Update CCS811 environmental data if BME280 reading was successful */
+		if (ret == 0) {
+			update_ccs811_env_data(ccs811_sensor, &temp, &hum);
 		}
+#endif /* CONFIG_CCS811_ENV_COMPENSATION */
 
-		ret = sensor_channel_get(sensor, SENSOR_CHAN_PRESS, &press);
+		/* Read CCS811 data (CO2 and VOC) */
+		ret = read_ccs811_data(ccs811_sensor, &co2, &voc);
 		if (ret < 0) {
-			LOG_ERR("Could not get pressure (%d)", ret);
-			continue;
+			LOG_ERR("Failed to read CCS811 data");
 		}
 
-		ret = sensor_channel_get(sensor, SENSOR_CHAN_HUMIDITY, &hum);
+		/* Read HM3301 data (PM1.0, PM2.5, PM10) */
+		ret = read_hm3301_data(hm3301_sensor, &pm1, &pm25, &pm10);
 		if (ret < 0) {
-			LOG_ERR("Could not get humidity (%d)", ret);
-			continue;
+			LOG_ERR("Failed to read HM3301 data");
 		}
 
-		LOG_INF("BME280: Temp: %d.%06d C, Press: %d.%06d kPa, Hum: %d.%06d %%", temp.val1,
-			temp.val2, press.val1, press.val2, hum.val1, hum.val2);
+		/* Log all sensor data */
+		log_sensor_data(&temp, &press, &hum, &co2, &voc, &pm1, &pm25, &pm10);
 
 		k_sleep(K_MSEC(1000));
 	}