dual_hx711_calibration.ino

//#include "HX711.h" //This library can be obtained here http://librarymanager/All#Avia_HX711
#include <HX711_2.h>
#define LOADCELL_DOUT_PIN1  12
#define LOADCELL_DOUT_PIN2  13
#define LOADCELL_SCK_PIN  11

HX711_2 scale;

float calibration_factor1 = 3900;
float calibration_factor2 = 2560;//-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_PIN1, LOADCELL_DOUT_PIN2, LOADCELL_SCK_PIN);
  scale.set_scale(calibration_factor1, calibration_factor2);
  scale.power_up();
  delay(500);
  scale.tare(5);	//Reset the scale to 0
}

void loop() {
  scale.set_scale(calibration_factor1, calibration_factor2); //Adjust to this calibration factor

  float values[2];
  scale.get_units(values);
  Serial.print("Reading: ");
  Serial.print(values[0]);
  Serial.print("g  "); //Change this to kg and re-adjust the calibration factor if you follow SI units like a sane person
  Serial.print(values[1]);
  Serial.print("g");
  Serial.print("  TOTAL: ");
  Serial.print(values[0] + values[1]);
  Serial.print("\t   F1: ");
  Serial.print(calibration_factor1);
   Serial.print(" F2: ");
  Serial.print(calibration_factor2);
  Serial.println();

  if(Serial.available())
  {
    char temp = Serial.read();
    if(temp == 'a')
      calibration_factor1 += 10;
    else if(temp == 'z')
      calibration_factor1 -= 10;
    else if(temp == 's')
      calibration_factor2 += 10;
    else if(temp == 'x')
      calibration_factor2 -= 10;
    else if(temp == 't')
      scale.tare(5);
  }
}