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DFRobot KIT0176: I2C 1kg Weight Sensor Kit - HX711 (Gravity: I2CWeight Sensor)

Binding for I2C interface for HX711 provided by DFRobot. Note that this binding does not provide way to communicate with HX711 directly.

Documentation

There is no official datasheet as of writing this document. Some resources with partial information are available though:

How to connect

Name PCB description
Sensor red wire E+
Sensor black wire E-
Sensor white wire S-
Sensor green wire S+

Usage

This specific sample uses FT4222 for I2C:

using System;
using System.Collections.Generic;
using System.Device.I2c;
using System.Threading;
using Iot.Device.Ft4222;
using Iot.Device.Hx711;

List<Ft4222Device> ft4222s = Ft4222Device.GetFt4222();
if (ft4222s.Count == 0)
{
    Console.WriteLine("FT4222 not plugged in");
    return;
}

Ft4222Device ft4222 = ft4222s[0];

// If using Raspberry Pi rather than FT4222 following initialization method can be used instead:
// using Hx711I2c hx711 = new(I2cDevice.Create(new I2cConnectionSettings(1, Hx711I2c.DefaultI2cAddress)));
using Hx711I2c hx711 = new(ft4222.CreateI2cDevice(new I2cConnectionSettings(0, Hx711I2c.DefaultI2cAddress)));
hx711.CalibrationScale = 2236.0f;
hx711.Tare(blinkLed: true);

// less accuracy but faster response time
hx711.SampleAveraging = 10;

// To simulate pressing CAL button:
// hx711.StartCalibration();
while (true)
{
    Console.WriteLine($"{hx711.GetWeight().Grams:0.0}g");
    Thread.Sleep(1000);
}

Calibration

  • Calibration starts when CAL button is pressed or hx711.StartCalibration() is called
  • When calibration starts orange LED will turn on
  • After that wait a bit (min 1 second up to 5 seconds) and place calibration weight (100g by default)
  • When weight is placed the calibration will be triggered automatically after around 1 second after placing the weight
  • When calibration is successful orange LED will blink 3 times
  • When calibration is not succesful orange LED will just turn off without blinking
  • Calibration weight can be specified using AutomaticCalibrationWeight
  • Weight triggering calibration (after CAL button is pressed) can be set using AutomaticCalibrationThreshold and is 10g by default
  • AutomaticCalibrationThreshold should be smaller than AutomaticCalibrationWeight
hx711.StartCalibration();

// when orange LED blinks 3 times this value can be read and assigned:
hx711.CalibrationScale = GetAutomaticCalibrationScale();

// The assignment is optional - it will also happen automatically when hx711.GetWeight() is called

Auto-calibration

See official documentation how to use CAL button