Meadow.Foundation.Sensors.LoadCell.Hx711

Hx711
Status
Source code	GitHub
Datasheet(s)	GitHub
NuGet package

Code Example

Hx711 loadSensor;

public int CalibrationFactor { get; set; } = 0; //9834945 - 8458935; // TODO: change this based on your scale (using the method provided below)
public double CalibrationWeight { get; set; } = 1.6; // TODO: enter the known-weight (in units below) you used in calibration

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

    loadSensor = new Hx711(Device.Pins.D04, Device.Pins.D03);

    if (CalibrationFactor == 0)
    {
        GetAndDisplayCalibrationUnits(loadSensor);
    }
    else
    {   // wait for the ADC to settle
        await Task.Delay(500);

        // Set the current load to be zero
        loadSensor.SetCalibrationFactor(CalibrationFactor, new Mass(CalibrationWeight, Mass.UnitType.Grams));
        loadSensor.Tare();
    }

    loadSensor.Updated += (sender, values) => Resolver.Log.Info($"Mass is now returned {values.New.Grams:N2}g");
}

public override Task Run()
{
    loadSensor.StartUpdating(TimeSpan.FromSeconds(2));

    return Task.CompletedTask;
}

public void GetAndDisplayCalibrationUnits(Hx711 sensor)
{   // first notify the user we're starting
    Resolver.Log.Info($"Beginning Calibration. First we'll tare (set a zero).");
    Resolver.Log.Info($"Make sure scale bed is clear. Next step in 5 seconds...");
    Thread.Sleep(5000);
    sensor.Tare();
    Resolver.Log.Info($"Place a known weight on the scale. Next step in 5 seconds...");
    Thread.Sleep(5000);
    var factor = sensor.CalculateCalibrationFactor();
    Resolver.Log.Info($"Your scale's Calibration Factor is: {factor}.  Enter this into the code for future use.");
}

Sample project(s) available on GitHub

Class Hx711

24-Bit Dual-Channel ADC For Bridge Sensors

Assembly: Hx711.dll

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Declaration

public class Hx711 : PollingSensorBase<Mass>, IObservable<IChangeResult<Mass>>, IMassSensor, ISamplingSensor<Mass>, ISensor<Mass>, ISensor, ISamplingSensor, IDisposable

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

Implements:
System.IObservable<Meadow.IChangeResult<Meadow.Units.Mass>>, Meadow.Peripherals.Sensors.Mass.IMassSensor, Meadow.Peripherals.Sensors.ISamplingSensor<Meadow.Units.Mass>, Meadow.Peripherals.Sensors.ISensor<Meadow.Units.Mass>, Meadow.Peripherals.Sensors.ISensor, Meadow.Peripherals.Sensors.ISamplingSensor, System.IDisposable

Properties

IsDisposed

Is the peripheral disposed

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Declaration

public bool IsDisposed { get; }

IsSleeping

Is the peripheral sleeping

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Declaration

public bool IsSleeping { get; }

Gain

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Declaration

public Hx711.AdcGain Gain { get; }

TareValue

Gets/Sets Tare value

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Declaration

public uint TareValue { get; set; }

DefaultSamplePeriod

Gets default sample period (1 Second)

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Declaration

public TimeSpan DefaultSamplePeriod { get; }

Mass

The last read Mass

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Declaration

public Mass? Mass { get; }

Methods

Sleep()

Puts the device into low-power sleep mode

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Declaration

public void Sleep()

Wake()

Takes the device out of low-power sleep mode

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Declaration

public void Wake()

Tare()

Tares the sensor, effectively setting the current weight reading to relative zero.

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Declaration

public void Tare()

CalculateCalibrationFactor()

Calculates the calibration factor of the load cell. Call this method with a known weight on the sensor, and then use the returned value in a call to Meadow.Foundation.Sensors.LoadCell.Hx711.SetCalibrationFactor(System.Int32%2cMeadow.Units.Mass) before using the sensor.

View Source

Declaration

public int CalculateCalibrationFactor()

Returns

System.Int32

SetCalibrationFactor(int, Mass)

Sets the sensor's calibration factor based on a factor calculated with a know weight by calling Meadow.Foundation.Sensors.LoadCell.Hx711.CalculateCalibrationFactor().

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Declaration

public void SetCalibrationFactor(int factor, Mass knownValue)

Parameters

Type	Name
System.Int32	factor
Meadow.Units.Mass	knownValue

ReadSensor()

Gets the current sensor weight

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Declaration

protected override Task<Mass> ReadSensor()

Returns

System.Threading.Tasks.Task<Meadow.Units.Mass>

Dispose(bool)

Dispose of the object

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Declaration

protected virtual void Dispose(bool disposing)

Parameters

Type	Name	Description
System.Boolean	disposing	Is disposing

Dispose()

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

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Declaration

public void Dispose()

Implements

• System.IObservable<Meadow.IChangeResult<Meadow.Units.Mass>>
• Meadow.Peripherals.Sensors.Mass.IMassSensor
• Meadow.Peripherals.Sensors.ISamplingSensor<Meadow.Units.Mass>
• Meadow.Peripherals.Sensors.ISensor<Meadow.Units.Mass>
• Meadow.Peripherals.Sensors.ISensor
• Meadow.Peripherals.Sensors.ISamplingSensor
• System.IDisposable