Meadow.Foundation.Sensors.Moisture.Fc28

Fc28
Status
Source code	GitHub
Datasheet(s)	GitHub
NuGet package

FC-28 Soil Moisture Sensor is a simple breakout for measuring the moisture in soil and similar materials. The sensor has two probes and measures the resistance between them, which means this sensor is of type Resistive. Since water is conductive, as moisture in the soil increases, the resistance decreases allowing the sensor to determine soil humidity.

The biggest issue of this sensor is the corrosion of the probes, not just because it is in contact with the soil but also because there is a DC current flowing which causes electrolysis of the sensors. A work-around to prolong the life of the probes is to not constantly have the sensor powered on, but activate it every time the sensor will perform a read using a digital output port connected to the VCC pin. The code and circuit example shows you how to use it.

The following example shows how read the soil moisture every second:

public class MeadowApp : App<F7Micro, MeadowApp>
{
    Fc28 fc28;

    public MeadowApp()
    {
        Console.WriteLine("Initializing...");

        fc28 = new Fc28(
            Device.CreateAnalogInputPort(Device.Pins.A01),
            Device.CreateDigitalOutputPort(Device.Pins.D15),
            minimumVoltageCalibration: 3.24f,
            maximumVoltageCalibration: 2.25f
        );

        TestFC28Updating();
    }

    void TestFC28Updating() 
    {
        Console.WriteLine("TestFC28Updating...");

        fc28.Subscribe(new FilterableObserver<FloatChangeResult, float>(
            h => { Console.WriteLine($"Moisture values: {Math.Truncate(h.New)}, old: {Math.Truncate(h.Old)}, delta: {h.DeltaPercent}"); },
            e => { return true; }
        ));

        fc28.Updated += (object sender, FloatChangeResult e) =>
        {
            Console.WriteLine($"Moisture Updated: {e.New}");
        };

        fc28.StartUpdating();
    }
}

Sample projects available on GitHub

Code Example

Fc28 fc28;

public override Task Initialize()
{
    Resolver.Log.Info("Initialize...");

    fc28 = new Fc28(
        Device.CreateAnalogInputPort(Device.Pins.A01, 5, TimeSpan.FromMilliseconds(40), new Voltage(3.3, Voltage.UnitType.Volts)),
        Device.CreateDigitalOutputPort(Device.Pins.D15),
        minimumVoltageCalibration: new Voltage(3.24f, VU.Volts),
        maximumVoltageCalibration: new Voltage(2.25f, VU.Volts)
    );

    var consumer = Fc28.CreateObserver(
        handler: result =>
        {
            // the first time through, old will be null.
            string oldValue = (result.Old is { } old) ? $"{old:n2}" : "n/a";
            Resolver.Log.Info($"Subscribed - " +
                $"new: {result.New}, " +
                $"old: {oldValue}");
        },
        filter: null
    );
    fc28.Subscribe(consumer);

    fc28.Updated += (object sender, IChangeResult<double> e) =>
    {
        Resolver.Log.Info($"Moisture Updated: {e.New}");
    };

    return Task.CompletedTask;
}

public async override Task Run()
{
    var moisture = await fc28.Read();
    Resolver.Log.Info($"Moisture Value {moisture}");

    fc28.StartUpdating(TimeSpan.FromMilliseconds(5000));
}

Sample project(s) available on GitHub

Wiring Example

Class Fc28

FC-28-D Soil Hygrometer Detection Module + Soil Moisture Sensor

Assembly: Fc28.dll

View Source

Declaration

public class Fc28 : PollingSensorBase<double>, IObservable<IChangeResult<double>>, IMoistureSensor, ISamplingSensor<double>, ISensor<double>, ISensor, ISamplingSensor, IDisposable

Inheritance: System.Object -> Meadow.Foundation.ObservableBase<UNIT>

Implements:
System.IObservable<Meadow.IChangeResult<System.Double>>, Meadow.Peripherals.Sensors.Moisture.IMoistureSensor, Meadow.Peripherals.Sensors.ISamplingSensor<System.Double>, Meadow.Peripherals.Sensors.ISensor<System.Double>, Meadow.Peripherals.Sensors.ISensor, Meadow.Peripherals.Sensors.ISamplingSensor, System.IDisposable

Properties

AnalogInputPort

Returns the analog input port

View Source

Declaration

protected IAnalogInputPort AnalogInputPort { get; }

DigitalOutputPort

Returns the digital output port

View Source

Declaration

protected IDigitalOutputPort DigitalOutputPort { get; }

Moisture

Last value read from the moisture sensor

View Source

Declaration

public double? Moisture { get; }

MinimumVoltageCalibration

Voltage value of most dry soil - default is 0 volts

View Source

Declaration

public Voltage MinimumVoltageCalibration { get; set; }

MaximumVoltageCalibration

Voltage value of most moist soil - default of 3.3V

View Source

Declaration

public Voltage MaximumVoltageCalibration { get; set; }

IsDisposed

Is the object disposed

View Source

Declaration

public bool IsDisposed { get; }

Methods

ReadSensor()

Reads data from the sensor

View Source

Declaration

protected override Task<double> ReadSensor()

Returns

System.Threading.Tasks.Task<System.Double>: The latest sensor reading### VoltageToMoisture(Voltage) Converts voltage to moisture value, ranging from 0 (most dry) to 1 (most wet)

View Source

Declaration

protected double VoltageToMoisture(Voltage voltage)

Returns

System.Double

Parameters

Type	Name
Meadow.Units.Voltage	voltage

Dispose()

Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.

View Source

Declaration

public void Dispose()

Dispose(bool)

Dispose of the object

View Source

Declaration

protected virtual void Dispose(bool disposing)

Parameters

Type	Name	Description
System.Boolean	disposing	Is disposing

Implements

• System.IObservable<Meadow.IChangeResult<System.Double>>
• Meadow.Peripherals.Sensors.Moisture.IMoistureSensor
• Meadow.Peripherals.Sensors.ISamplingSensor<System.Double>
• Meadow.Peripherals.Sensors.ISensor<System.Double>
• Meadow.Peripherals.Sensors.ISensor
• Meadow.Peripherals.Sensors.ISamplingSensor
• System.IDisposable