The Weight Sensor Load Cell 20kg With HX711 A/D Module is a digital load cell weight sensor. good for diverse applications, from portable electronic kitchen scales to innovative Arduino projects, this module is a powerhouse of accuracy and functionality. At its core, this module employs a high-precision 24-bit A/D converter chip, the hx711, ensuring meticulous measurements in every scenario. Integrating a 128 times programmable gain amplifier further enhances precision, setting it apart in the realm of load cell sensors. With the flexibility to configure its input circuit for a bridge-type pressure mode, this module excels in applications that demand high precision and cost-effectiveness. It becomes the sampling front-end module of choice, providing your projects with a reliable stream of accurate data. Equipped with two selectable differential input channels, an on-chip active low noise PGA with adjustable gains, and an on-chip power supply regulator, this module goes beyond the ordinary. Its simplicity extends to digital control and a serial interface, requiring no programming effort – just seamless integration into your project. the module boasts a built-in oscillator, eliminating the need for external components, and offers selectable output data rates of 10SPS or 80SPS.

Features:

• Two selectable differential input channels
• On-chip active low noise PGA with selectable gain of 3264 and 128
• On-chip power supply regulator for load-cell and ADC analog power supply
• On-chip oscillator requiring no external component with optional external crystal
• On-chip power-on-reset
• Simple digital control and serial interface: pin-driven controlsno programming needed
• Selectable 10SPS or 80SPS output data rate
• Simultaneous 50 and 60Hz supply rejection

Specification:

• HX711:
  • Operating Voltage: 2.7 - 5VDC.
  • Differential input voltage: ±40mV
  • Data accuracy: 24-bit
  • Refresh frequency: 10/80 Hz.
  • Operating current: < 1.5 mA
  • Standby current: < 1 uA
  • Dimension: 24 x 16mm
• 20Kg load sensor:
  • Capacity: 10 - 20 Kg
  • Input Resistance: 1000 ± 20 Ω
  • Output Resistance: 1000 ± 20 Ω
  • Resistance: MΩ ≥5000
  • Excitation Voltage: V ≤10
  • RangeL: 0 – +50 Deg C
  • Overload Capacity: 150% F.S
  • Dimension: 80 x 12.7 x 12.7mm

Applications:

• Kitchen scales: The module can be used in digital kitchen scales to accurately measure the weight of ingredients for cooking or baking.
• Weighing systems: The module can be used in various weighing systems, such as industrial weighing, postal scales, and luggage scales.

Pin Connections:

• Weight Sensor:

• HX711 Module:

  

Package Includes:

• 1 x 20KG Weight Sensor
• 1 x HX711 24BIT Precision ADC Module

Sample Project:

Circuit:

Library:

• The HX711 library is available here: https://github.com/bogde/HX711
• See this link on the Arduino website for instructions on how to add the library to your Arduino IDE: https://www.arduino.cc/en/Guide/Libraries
• Sparkfun has great Arduino programs to run the scale. The most up to date versions are available on GitHub and reprinted below: https://github.com/sparkfun/HX711-Load-Cell-Amplifier

Code:

• The first software step is to determine calibration factors for the scale. To do this, run this code:

/*
 Example using the SparkFun HX711 breakout board with a scale

 This is the calibration sketch. Use it to determine the calibration_factor that the main example uses. It also
 outputs the zero_factor useful for projects that have a permanent mass on the scale in between power cycles.

 Setup your scale and start the sketch WITHOUT a weight on the scale
 Once readings are displayed place the weight on the scale
 Press +/- or a/z to adjust the calibration_factor until the output readings match the known weight
 Use this calibration_factor on the example sketch

 This example assumes pounds (lbs). If you prefer kilograms, change the Serial.print(" lbs"); line to kg. The
 calibration factor will be significantly different but it will be linearly related to lbs (1 lbs = 0.453592 kg).

 Your calibration factor may be very positive or very negative. It all depends on the setup of your scale system
 and the direction the sensors deflect from zero state
 This example code uses bogde's excellent library:"https://github.com/bogde/HX711"
 bogde's library is released under a GNU GENERAL PUBLIC LICENSE
 Arduino pin 2 -> HX711 CLK
 3 -> DOUT
 5V -> VCC
 GND -> GND

 Most any pin on the Arduino Uno will be compatible with DOUT/CLK.

 The HX711 board can be powered from 2.7V to 5V so the Arduino 5V power should be fine.

*/

#include "HX711.h"

#define LOADCELL_DOUT_PIN  3
#define LOADCELL_SCK_PIN  2

HX711 scale;

float calibration_factor = -7050; //-7050 worked for my 440lb max scale setup

void setup()
{
    Serial.begin(9600);
    Serial.println("HX711 calibration sketch");
    Serial.println("Remove all weight from scale");
    Serial.println("After readings begin, place known weight on scale");
    Serial.println("Press + or a to increase calibration factor");
    Serial.println("Press - or z to decrease calibration factor");

    scale.begin(LOADCELL_DOUT_PIN, LOADCELL_SCK_PIN);
    scale.set_scale();
    scale.tare(); //Reset the scale to 0

    long zero_factor = scale.read_average(); //Get a baseline reading
    Serial.print("Zero factor: "); //This can be used to remove the need to tare the scale. Useful in permanent scale projects.
    Serial.println(zero_factor);
}

void loop()
{

    scale.set_scale(calibration_factor); //Adjust to this calibration factor
    Serial.print("Reading: ");
    Serial.print(scale.get_units(), 1);
    Serial.print(" lbs"); //Change this to kg and re-adjust the calibration factor if you follow SI units like a sane person
    Serial.print(" calibration_factor: ");
    Serial.print(calibration_factor);
    Serial.println();

    if(Serial.available())

    {
        char temp = Serial.read();
        if(temp == '+' || temp == 'a')
        calibration_factor += 10;
        else if(temp == '-' || temp == 'z')
        calibration_factor -= 10;
    }
}

• After calibrating the scale, you can run this sample program, then hack it up for your own purposes:

/*
 Example using the SparkFun HX711 breakout board with a scale

 This example demonstrates basic scale output. See the calibration sketch to get the calibration_factor for your
 specific load cell setup.

 This example code uses bogde's excellent library:"https://github.com/bogde/HX711"
 bogde's library is released under a GNU GENERAL PUBLIC LICENSE

 The HX711 does one thing well: read load cells. The breakout board is compatible with any wheat-stone bridge
 based load cell which should allow a user to measure everything from a few grams to tens of tons.
 Arduino pin 2 -> HX711 CLK
 3 -> DAT
 5V -> VCC
 GND -> GND

 The HX711 board can be powered from 2.7V to 5V so the Arduino 5V power should be fine.

*/

#include "HX711.h"

#define calibration_factor -7050.0 //This value is obtained using the SparkFun_HX711_Calibration sketch

#define LOADCELL_DOUT_PIN  3
#define LOADCELL_SCK_PIN  2

HX711 scale;

void setup()
{
    Serial.begin(9600);
    Serial.println("HX711 scale demo");

    scale.begin(LOADCELL_DOUT_PIN, LOADCELL_SCK_PIN);
    scale.set_scale(calibration_factor); //This value is obtained by using the SparkFun_HX711_Calibration sketch
    scale.tare(); //Assuming there is no weight on the scale at start up, reset the scale to 0

    Serial.println("Readings:");
}

void loop()
{
    Serial.print("Reading: ");
    Serial.print(scale.get_units(), 1); //scale.get_units() returns a float
    Serial.print(" lbs"); //You can change this to kg but you'll need to refactor the calibration_factor
    Serial.println();
}

References:

• https://www.instructables.com/How-to-Interface-HX711-Balance-Module-With-Load-Ce/
• https://github.com/aguegu/ardulibs/tree/master/hx711
• https://cdn.sparkfun.com/datasheets/Sensors/ForceFlex/hx711_english.pdf
• https://www.youtube.com/watch?v=nGUpzwEa4vg