Remarks

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.MassUpdated += (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

Characteristic	Locus
Inheritance	System.Object ObservableBase<Mass> SamplingSensorBase<Mass> PollingSensorBase<Mass> > Hx711
Implements	ISamplingSensor<Mass> ISamplingSensor<Mass> IMassSensor IDisposable
Inherited Members	PollingSensorBase<Mass>.StartUpdating(Nullable<TimeSpan>) PollingSensorBase<Mass>.StopUpdating() SamplingSensorBase<Mass>.samplingLock SamplingSensorBase<Mass>.Updated SamplingSensorBase<Mass>.SamplingTokenSource SamplingSensorBase<Mass>.Conditions SamplingSensorBase<Mass>.IsSampling SamplingSensorBase<Mass>.UpdateInterval SamplingSensorBase<Mass>.RaiseEventsAndNotify(IChangeResult<>) SamplingSensorBase<Mass>.Read() ObservableBase<Mass>.observers ObservableBase<Mass>.NotifyObservers(IChangeResult<>) Meadow.Foundation.ObservableBase<Mass>.Subscribe(IObserver<>) Meadow.Foundation.ObservableBase<Mass>.CreateObserver(Action<>, System.Nullable<Predicate<IChangeResult<UNIT>>>)
Namespace	Meadow.Foundation.Sensors.LoadCell
Assembly	Hx711.dll

Syntax

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

Constructors

Hx711(IDigitalOutputPort, IDigitalInputPort, Nullable<UInt32>)

Creates an instance of the Hx711 Driver class

Declaration

public Hx711(IDigitalOutputPort sck, IDigitalInputPort dout, uint? tareValue = null)

Parameters

Type	Name	Description
IDigitalOutputPort	sck
IDigitalInputPort	dout
System.Nullable<System.UInt32>	tareValue

Hx711(IPin, IPin, Nullable<UInt32>)

Creates an instance of the Hx711 Driver class

Declaration

public Hx711(IPin sck, IPin dout, uint? tareValue = null)

Parameters

Type	Name	Description
IPin	sck	Serial clock pin
IPin	dout	Digital output pin
System.Nullable<System.UInt32>	tareValue	Tare value threshold

Properties

DefaultSamplePeriod

Gets default sample period (1 Second)

Declaration

public TimeSpan DefaultSamplePeriod { get; }

Property Value

Type	Description
TimeSpan

Gain

Declaration

public Hx711.AdcGain Gain { get; }

Property Value

Type	Description
Hx711.AdcGain

IsDisposed

Is the peripheral disposed

Declaration

public bool IsDisposed { get; }

Property Value

Type	Description
System.Boolean

IsSleeping

Is the peripheral sleeping

Declaration

public bool IsSleeping { get; }

Property Value

Type	Description
System.Boolean

Mass

The last read Mass

Declaration

public Mass? Mass { get; }

Property Value

Type	Description
System.Nullable<Mass>

TareValue

Gets/Sets Tare value

Declaration

public uint TareValue { get; set; }

Property Value

Type	Description
System.UInt32

Methods

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 SetCalibrationFactor(Int32, Mass) before using the sensor.

Declaration

public int CalculateCalibrationFactor()

Returns

Type	Description
System.Int32

Dispose()

Dispose managed resources

Declaration

public void Dispose()

Dispose(Boolean)

Dispose managed resources

Declaration

protected virtual void Dispose(bool disposing)

Parameters

Type	Name	Description
System.Boolean	disposing	Is disposing

RaiseEventsAndNotify(IChangeResult<Mass>)

Inheritance-safe way to raise events and notify observers.

Declaration

protected override void RaiseEventsAndNotify(IChangeResult<Mass> changeResult)

Parameters

Type	Name	Description
IChangeResult<Mass>	changeResult

ReadSensor()

Gets the current sensor weight

Declaration

protected override Task<Mass> ReadSensor()

Returns

Type	Description
Task<Mass>

Overrides

Meadow.Foundation.SamplingSensorBase<Mass>.ReadSensor()

SetCalibrationFactor(Int32, Mass)

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

Declaration

public void SetCalibrationFactor(int factor, Mass knownValue)

Parameters

Type	Name	Description
System.Int32	factor
Mass	knownValue

Sleep()

Puts the device into low-power sleep mode

Declaration

public void Sleep()

Tare()

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

Declaration

public void Tare()

Wake()

Takes the device out of low-power sleep mode

Declaration

public void Wake()

Events

MassUpdated

Mass changed event

Declaration

public event EventHandler<IChangeResult<Mass>> MassUpdated

Event Type

Type	Description
EventHandler<IChangeResult<Mass>>