//HX711 라이브러리 다운로드 https://github.com/bogde/HX711
// 로드셀의 측정값을 calibration 하는 예제입니다.

#include "HX711.h"

#define DOUT  3
#define CLK  2

HX711 scale(DOUT, CLK);

float calibration_factor = -7050; //440lb로 교정을 위한 팩터

void setup() {  //초기화
  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.set_scale();
  scale.tare(); //Reset the scale to 0

  long zero_factor = scale.read_average();
  Serial.print("Zero factor: "); 
  Serial.println(zero_factor);
}

void loop() { //무한루프

  scale.set_scale(calibration_factor); //calibration 참조

  Serial.print("Reading: ");
  Serial.print(scale.get_units(), 1);
  Serial.print(" lbs"); //kg, lbs 등 무게단위 설정
  Serial.print(" calibration_factor: ");
  Serial.print(calibration_factor);
  Serial.println();

  if(Serial.available())
  {
    char temp = Serial.read();
    if(temp == '+' || temp == 'a')  // +, a 입력시 cailbration +10
      calibration_factor += 10;
    else if(temp == '-' || temp == 'z') // -, z 입력시 calibration -10
      calibration_factor -= 10;
  }
}