Meadow.Foundation.Sensors.Moisture.Capacitive

Capacitive
Status
Source code	GitHub
NuGet package

Capacitive Soil Moisture sensor is a simple breakout for measuring the moisture in soil and similar materials. This sensor measures moisture levels by capacitive sensing, rather then resistive sensing like other types of moisture sensor such as the FC-28.

Capacitive sensing means measuring the dielectrum that is formed by the soil and the water is the most important factor that forms the dielectrum. Even though this kind of sensor might be a little pricier, it is made of corrosion resistant material giving it a longer service of life than a resistive sensor.

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

public class MeadowApp : App<F7Micro, MeadowApp>
{
    Capacitive _Capacitive;

    public MeadowApp()
    {
        // create a new Capacitive sensor object connected to analog pin A01
        _Capacitive = new Capacitive(Device.Pins.A01);

        Run();
    }

    async Task Run()
    {
        while (true)
        {
            float moisture = await _Capacitive.Read();
            Console.WriteLine($"Moisture: {0}", moisture);
            Thread.Sleep(1000);
        }
    }
}

Sample projects available on GitHub

Code Example

Capacitive capacitive;

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

    capacitive = new Capacitive(
        Device.Pins.A00,
        minimumVoltageCalibration: new Voltage(2.84f),
        maximumVoltageCalibration: new Voltage(1.63f)
    );

    // Example that uses an IObservable subscription to only be notified when the moisture changes by filter defined.
    var consumer = Capacitive.CreateObserver(
        handler: result =>
        {
            string oldValue = (result.Old is { } old) ? $"{old:n2}" : "n/a";
            Resolver.Log.Info($"Subscribed - " +
                $"new: {result.New}, " +
                $"old: {oldValue}");
        },
        filter: null
    );
    capacitive.Subscribe(consumer);

    // classical .NET events can also be used:
    capacitive.Updated += (sender, result) =>
    {
        string oldValue = (result.Old is { } old) ? $"{old:n2}" : "n/a";
        Resolver.Log.Info($"Updated - New: {result.New}, Old: {oldValue}");
    };

    //==== One-off reading use case/pattern
    ReadSensor().Wait();

    capacitive.StartUpdating(TimeSpan.FromMilliseconds(1000));

    return Task.CompletedTask;
}

protected async Task ReadSensor()
{
    var moisture = await capacitive.Read();
    Resolver.Log.Info($"Initial moisture: {moisture:n2}");
}

Sample project(s) available on GitHub

Code Example​

Wiring Example​

Code Example

Wiring Example