Add support for YF-S201 flow rate sensor

README.md

@@ -44,6 +44,7 @@ Hardware support is provided by specific GPIO, Sensor and Stream modules. It's e
   - ADXl345 3-axis accelerometer up to ±16g  (`adxl345`)
   - PMS5003 particulate sensor (`pms5003`)
   - SHT40/SHT41/SHT45 temperature and humidity sensors (`sht4x`)
+  - YF-S201 flow rate sensor (`yfs201`)
 
 ### Streams
 

mqtt_io/modules/sensor/yfs201.py

@@ -0,0 +1,95 @@
+"""
+
+YF-S201 Flow Rate Sensor
+
+Example configuration:
+
+sensor_modules:
+  - name: yfs201
+    module: yfs201
+
+sensor_inputs:
+  - name: flow_rate1
+    module: yfs201
+    pin: 0
+    digits: 0
+    interval: 10
+    
+"""
+
+from typing import Dict, cast
+from ...types import CerberusSchemaType, ConfigType, SensorValueType
+from . import GenericSensor
+
+REQUIREMENTS = ("gpiozero",)
+
+
+class YFS201:
+    """
+    YF-S201 Flow Rate Sensor class
+    Multiple instances support multiple sensors on different pins
+    """
+
+    def __init__(self, gpiozero, name: str, pin: int) -> None:
+        self.name = name
+        self.pin = gpiozero.DigitalInputDevice(pin)
+        self.pin.when_activated = self.count_pulse
+        self.count = 0
+
+    def count_pulse(self) -> None:
+        """Increment pulse count."""
+        self.count += 1
+
+    def reset_count(self) -> None:
+        """Reset pulse count."""
+        self.count = 0
+
+    def flow_rate(self, sample_window: int) -> float:
+        """Return flow rate in liters per minute.
+
+        From YF-S201 manual:
+        Pluse Characteristic:F=7Q(L/MIN).
+        2L/MIN=16HZ 4L/MIN=32.5HZ 6L/MIN=49.3HZ 8L/MIN=65.5HZ 10L/MIN=82HZ
+
+        Pulse frequency (Hz) / 7.0 = flow rate in L/min
+
+        sample_window is in seconds, so hz is pulse_count / sample_window
+        """
+        hertz = self.count / sample_window
+        return hertz / 7.0
+
+    def get_value(self, interval: int) -> float:
+        """Return flow rate in L/min over interval seconds and reset count."""
+        flow_rate = cast(float, self.flow_rate(interval))
+        self.reset_count()
+        return flow_rate
+
+
+class Sensor(GenericSensor):
+    """
+    YF-S201 Flow Rate Sensor
+    """
+
+    SENSOR_SCHEMA: CerberusSchemaType = {
+        "pin": dict(
+            type="integer",
+            required=True,
+            empty=False,
+        )
+    }
+
+    def setup_module(self) -> None:
+        # pylint: disable=import-outside-toplevel,import-error
+        import gpiozero  # type: ignore
+
+        self.gpiozero = gpiozero
+        self.sensors: Dict[str, YFS201] = {}
+
+    def setup_sensor(self, sens_conf: ConfigType) -> None:
+        sensor = YFS201(
+            gpiozero=self.gpiozero, name=sens_conf["name"], pin=sens_conf["pin"]
+        )
+        self.sensors[sensor.name] = sensor
+
+    def get_value(self, sens_conf: ConfigType) -> SensorValueType:
+        return self.sensors[sens_conf["name"]].get_value(sens_conf["interval"])