Support for ENS160 digital multi-gas sensor with multiple IAQ data (T…

…VOC, eCO2, AQI) (#371)

* ENS160 sensor based on adafruit circultpython

README.md

@@ -37,6 +37,7 @@ Hardware support is provided by specific GPIO, Sensor and Stream modules. It's e
   - BME680 temperature, humidity and pressure sensor (`bme680`)
   - DHT11/DHT22/AM2302 temperature and humidity sensors (`dht22`)
   - DS18S20/DS1822/DS18B20/DS1825/DS28EA00/MAX31850K temperature sensors (`ds18b`)
+  - ENS160  digital multi-gas sensor with multiple IAQ data (TVOC, eCO2, AQI) (`ens160`)
   - HCSR04 ultrasonic range sensor (connected to the Raspberry Pi on-board GPIO) (`hcsr04`)
   - INA219 DC current sensor (`ina219`)
   - LM75 temperature sensor (`lm75`)

mqtt_io/modules/sensor/ens160.py

@@ -0,0 +1,125 @@
+"""
+ENS160 Air Quality Sensor
+
+sensor_modules:
+  - name: ens160
+    module: ens160
+    chip_addr: 0x53
+    temperature_compensation: 25
+    humidity_compensation: 50
+
+sensor_inputs:
+  - name: air_quality
+    module: ens160
+    interval: 10
+    digits: 0
+    type: aqi
+
+  - name: volatile_organic_compounds
+    module: ens160
+    interval: 10
+    digits: 0
+    type: tvoc
+
+  - name: eco2
+    module: ens160
+    interval: 10
+    digits: 0
+    type: eco2
+"""
+
+from typing import cast
+
+from ...types import CerberusSchemaType, ConfigType
+from . import GenericSensor
+
+DEFAULT_CHIP_ADDR = 0x53
+DEFAULT_TEMPERATURE_COMPENSATION = 25
+DEFAULT_HUMIDITY_COMPENSATION = 50
+
+
+REQUIREMENTS = ("adafruit-circuitpython-ens160",)
+CONFIG_SCHEMA: CerberusSchemaType = {
+    "chip_addr": dict(
+        type="integer", required=False, empty=False, default=DEFAULT_CHIP_ADDR
+    ),
+    "temperature_compensation": dict(
+        type="float",
+        required=False,
+        empty=False,
+        default=DEFAULT_TEMPERATURE_COMPENSATION,
+    ),
+    "humidity_compensation": dict(
+        type="float",
+        required=False,
+        empty=False,
+        default=DEFAULT_HUMIDITY_COMPENSATION,
+    ),
+}
+
+
+class Sensor(GenericSensor):
+    """
+    Implementation of Sensor class for the ENS160 sensor using adafruit-circuitpython-ens160.
+
+    Mesures:
+    AQI: The air quality index calculated on the basis of UBA
+    Return value: 1-Excellent, 2-Good, 3-Moderate, 4-Poor, 5-Unhealthy
+
+    TVOC: Total Volatile Organic Compounds concentration
+    Return value range: 0–65000, unit: ppb
+
+    CO2 equivalent concentration calculated according to the detected data of VOCs and hydrogen
+    Return value range: 400–65000, unit: ppm
+
+    Five levels: Excellent(400 - 600), Good(600 - 800), Moderate(800 - 1000),
+                 Poor(1000 - 1500), Unhealthy(> 1500)
+
+    NB: Need to think about how to handle the ambient_temp and relative_humidity values as
+        they are currently hard-coded defaults that can be overridden by user configuration.
+        Ideally these values would be read from a separate temperature/humdity sensor.
+    """
+
+    SENSOR_SCHEMA: CerberusSchemaType = {
+        "type": dict(
+            type="string",
+            required=False,
+            empty=False,
+            default="aqi",
+            allowed=["aqi", "tvoc", "eco2"],
+        ),
+    }
+
+    def setup_module(self) -> None:
+        # pylint: disable=import-outside-toplevel,import-error
+        import adafruit_ens160  # type: ignore
+        import board  # type: ignore
+
+        self.adafruit_ens160_module = adafruit_ens160
+        i2c = board.I2C()  # uses board.SCL and board.SDA
+        self.ens160 = adafruit_ens160.ENS160(i2c, address=self.config["chip_addr"])
+        self.ens160.temperature_compensation = self.config["temperature_compensation"]
+        self.ens160.humidity_compensation = self.config["humidity_compensation"]
+
+    def get_value(self, sens_conf: ConfigType) -> float:
+        """Return the sensor value in the configured type."""
+
+        # data_validity  values:
+        # NORMAL_OP - Normal operation,
+        # WARM_UP - Warm-Up phase, first 3 minutes after power-on.
+        # START_UP - Initial Start-Up phase, first full hour of operation after initial power-on.
+        #             Only once in the sensor’s lifetime.
+        # INVALID_OUT - Invalid output
+        # note: Note that the status will only be stored in the non-volatile memory after an initial
+        #       24h of continuous operation. If unpowered before conclusion of said period, the
+        #       ENS160 will resume "Initial Start-up" mode after re-powering.
+        if self.ens160.data_validity == self.adafruit_ens160_module.INVALID_OUT:
+            raise RuntimeError("ENS160 sensor is returning invalid output")
+
+        sens_type = sens_conf["type"]
+        return cast(
+            int,
+            dict(aqi=self.ens160.AQI, tvoc=self.ens160.TVOC, eco2=self.ens160.eCO2)[
+                sens_type
+            ],
+        )