/*
https://forum.arduino.cc/t/i-need-help-with-soil-ph-sensor-and-rs485/1259395

*/



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

const int phPin = A0;


float voltage = 0.0;
float phValue = 0.0;


LiquidCrystal_I2C lcd(0x27, 16, 2);

void setup() {
  Serial.begin(4800);

  lcd.begin(16,2);
  lcd.backlight();
  lcd.setCursor(0,0);
  lcd.print("pH Sensor");
}

void loop() {

  int sensorValue = analogRead(phPin);
  
  voltage = sensorValue * (5.0 / 1023.0);

  // Formula: measuring PH value = ((9-3)/(5-0) * voltage) + 3
  phValue = ((9.0 - 3.0) / (5.0 - 0.0)) * voltage + 3.0;

  Serial.print("Voltage: ");
  Serial.print(voltage);
  Serial.print(" V, pH Value: ");
  Serial.println(phValue);

  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Voltage: ");
  lcd.print(voltage, 2);
  lcd.print(" V");
  lcd.setCursor(0, 1);
  lcd.print("pH Value: ");
  lcd.print(phValue, 2);

   
  delay(2000);
}