Hx711 (M5Stack WEIGHT)

This is a library to interact with the Hx711 ADC. This is conveniently assembled and package in the M5Stack WEIGHT module.

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Documentation

  • The module documentation can be found here.
  • Datasheet for the Hx711 ADC can be found here.

Usage

Important: make sure you setup the SPI pins for ESP32 before creating the Scale. For this, make sure you install the nanoFramework.Hardware.ESP32 NuGet:

///////////////////////////////////////////////////////////////////////
// When connecting to an ESP32 device, need to configure the SPI GPIOs
// The following mapping is used in order to connect the WEIGTH module
// to a M5Core device using the Grove port A
// MOSI: connects to Grove pin 1
// MISO: connects to Grove pin 2
// CLOCK: connect to any free port as it's not used at all
Configuration.SetPinFunction(21, DeviceFunction.SPI1_MOSI);
Configuration.SetPinFunction(22, DeviceFunction.SPI1_MISO);
Configuration.SetPinFunction(23, DeviceFunction.SPI1_CLOCK);

For other devices, like STM32, please make sure you're using the pins for the UART you want to use.

// setup SPI connection settings
// the clock value was adjusted in order to get the typical duration expected by the PD_SCK ~1us
var spisettings = new SpiConnectionSettings(1, 19)
{
    ClockFrequency = Scale.DefaultClockFrequency
};

// create SPI device
var spidev = SpiDevice.Create(spisettings);

// create scale
var scale = new Scale(spidev);

The scale class is very simple to use and offers some configurations. Let's explore the most common usage scenarios.

Taring a scale

Taring is used to exclude a measurement from the total weight given by the scale. Most commonly, this function is used to negate the weight of the container or other elements attached to the scale.

// set scale tare to get accurate readings
scale.Tare();

Reading the weight

To take a reading of the weight on the load cell just need to call Read. The following code snippet will read the weight continuously and output the value to the output pane.


// loop forever outputting the current reading
while (true)
{
    var reading = scale.Read();

    Console.WriteLine($"Weight: {reading}");

    Thread.Sleep(2_000);
}

Settings and configurations

The library exposes several configurations. Please explore the documentation here.

Acknowledgments

The development of this library was kindly sponsored by greenYng!

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