HX711 Calibration for Arduino

hx711_calibration.ino

/*
 Started with example code written by Nathan Seidle from SparkFun Electronics and added
 LCD output with gram and ounce values.
 
 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

 Arduino pin 6 -> HX711 CLK
 Arduino pin 5 -> HX711 DOUT
 Arduino pin 5V -> HX711 VCC
 Arduino pin GND -> HX711 GND
 
 The HX711 board can be powered from 2.7V to 5V so the Arduino 5V power should be fine.
 
 The HX711 library can be downloaded from here: https://github.com/bogde/HX711
*/

#include <LiquidCrystal.h>
LiquidCrystal lcd(51, 50, 49, 48, 47, 46);


#include "HX711.h"

#define DOUT 5
#define CLK  6

HX711 scale(DOUT, CLK);

float calibration_factor = 2125; //-7050 worked for my 440lb max scale setup
float units;
float ounces;

void setup() {
  Serial.begin(9600);
  // set up the LCD's number of columns and rows:
  lcd.begin(20, 4);
  lcd.setCursor(0, 0);
  lcd.print("HX711 calibration");
  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.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: ");
  units = scale.get_units(), 10;
  if (units < 0) {
    units = 0.00;
  }
  ounces = units * 0.035274; //Convert grams to ounces
  Serial.print(units);
  Serial.print(" grams"); 
  Serial.print(" calibration_factor: ");
  Serial.print(calibration_factor);
  Serial.println();
  lcd.setCursor(0, 1);
  lcd.print("Grams: ");
  lcd.print(units);
  lcd.setCursor(0, 2);
  lcd.print("Ounce: ");
  lcd.print(ounces);
  lcd.setCursor(0, 3);
  lcd.print("Calbr: ");
  lcd.print(calibration_factor);

  if(Serial.available())
  {
    char temp = Serial.read();
    if(temp == '+' || temp == 'a')
      calibration_factor += 1;
    else if(temp == '-' || temp == 'z')
      calibration_factor -= 1;
  }
}

In line 59 you wrote: units = scale.get_units(), 10; What it really means?

Number 10 is not an argument of get units function, but rather the number of times that some function will be rolled but it is outside funcion variables ().

Hi,
Something seems strange on line 30 ;

`float calibration_factor = 2125; //-7050 worked for my 440lb max scale setup'

2125 seems to be :

• a constant
• an unsigned integer

Best.