#include <Wire.h>
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27, 16, 2);

#define S0 4
#define S1 5
#define S2 7
#define S3 6
#define sensorOut 8

int frequency = 0;
int color = 0;


void setup() {
  lcd.init();
  lcd.init();
  lcd.backlight();
  lcd.setCursor(0, 0);
  lcd.print("Scanning: ...");
  delay(5000);
  Serial.begin(115200);
  pinMode(S0, OUTPUT);
  pinMode(S1, OUTPUT);
  pinMode(S2, OUTPUT);
  pinMode(S3, OUTPUT);
  pinMode(sensorOut, INPUT);
  digitalWrite(S0, HIGH);
  digitalWrite(S1, LOW);
}


void loop() {

  color = readColor();
  delay(10);
  switch (color) {
    case 1:
      Serial.println("\t\t\tRED detected!");
      lcd.setCursor(0, 1);
      //        "****************"
      lcd.print("RED detected    ");
      break;
    case 2:
      Serial.println("\t\t\tBLUE detected!");
      lcd.setCursor(0, 1);
      //        "****************"
      lcd.print("BLUE detected   ");
      break;
    case 3:
      Serial.println("\t\t\tGREEN detected!");
      lcd.setCursor(0, 1);
      //        "****************"
      lcd.print("GREEN detected  ");
      break;
    case 4:
      Serial.println("\t\t\tYELLOW detected!");
      lcd.setCursor(0, 1);
      //        "****************"
      lcd.print("YELLOW detected ");
      break;
    case 0:
      lcd.setCursor(0, 1);
      //        "****************"
      lcd.print("                ");
      break;
  }
  color = 0;

}


//Read-Color Function

int readColor() {

  ////////////////////////////////////////////////////////

  //Setting red filtered photodiodes to be read

  digitalWrite(S2, LOW);
  digitalWrite(S3, LOW);


  //Reading the output frequency
  frequency = pulseIn(sensorOut, LOW);
  int R = frequency;
  //Printing the value on the serial monitor
  Serial.print("R= ");  //printing name
  Serial.print(frequency);  //printing RED color frequency
  Serial.print("  ");
  delay(50);

  ////////////////////////////////////////////////////////

  //Setting Green filtered photodiodes to be read

  digitalWrite(S2, HIGH);
  digitalWrite(S3, HIGH);

  //Reading the output frequency
  frequency = pulseIn(sensorOut, LOW);
  int G = frequency;

  //Printing the value on the serial monitor
  Serial.print("G= ");  //printing name
  Serial.print(frequency);  //printing RED color frequency
  Serial.print("  ");
  delay(50);

  ////////////////////////////////////////////////////////

  //Setting Blue filtered photodiodes to be read

  digitalWrite(S2, LOW);
  digitalWrite(S3, HIGH);

  //Reading the output frequency
  frequency = pulseIn(sensorOut, LOW);
  int B = frequency;

  //Printing the value on the serial monitor
  Serial.print("B= ");  //printing name
  Serial.print(frequency);  //printing RED color frequency
  Serial.println("  ");
  delay(50);

  ////////////////////////////////////////////////////////

  if (R < 60 && R > 20 && G < 150 && G > 40 && B < 150 && B > 40  ) {
    color = 1; // Red
  }
  else if (R < 150 && R > 20 && G < 150 && G > 20 && B < 20 && B > 10  ) {
    color = 2; // Blue
  }
  else if (R < 70 && R > 30 && G < 40 && G > 10 && B < 70 && B > 30  ) {
    color = 3; // Green
  }
  else if (R < 20 && R > 10 && G < 40 && G > 20 && B < 50 && B > 20  ) {
    color = 4; // YELLOW
  }
  return color;
}