#include <Wire.h> 
#include <LiquidCrystal_I2C.h> 

#define col 16 
#define lin  2 
#define ende  0x27 

int pHSense = A0;
int samples = 10;
float adc_resolution = 1024.0;

LiquidCrystal_I2C lcd(ende,col,lin);

void setup()
{
  Serial.begin(9600);
  lcd.init();
  lcd.backlight(); 
  lcd.clear();
  delay(100);
}

float ph (float voltage) {
    return 7 + ((2.5 - voltage) / 0.18);
}

void loop()
{
  lcd.setCursor(0, 0);
  Serial.println("Valor ph");
    int measurings=0;

    for (int i = 0; i < samples; i++)
    {
        measurings += analogRead(pHSense);
        delay(10);

    }

    float voltage = 5 / adc_resolution * measurings/samples;
    Serial.print("pH= ");
    Serial.println(ph(voltage));
    lcd.setCursor(0, 1);
    lcd.print(ph(voltage));
    delay(3000);
    lcd.clear();
}