#include <Keypad.h> // import Keypad


#define LED_G 10 
#define LED_Y 9
#define LED_R 8

const int ROW_NUM = 4;
const int COLUMN_NUM = 4;

char keys[ROW_NUM][COLUMN_NUM] = {
{'1','2','3','A'},
{'4','5','6','B'},
{'7','8','9','C'},
{'*','0','#','D'}
};

byte pin_rows[ROW_NUM] = {7, 6, 5, 4}; //connect to the row pinouts of the keypad
byte pin_column[COLUMN_NUM] = {3, 2, 1, 0}; //connect to the column pinouts of the keypad

void setup()
{
  Serial.begin(9600);
  pinMode(LED_G, OUTPUT);
  pinMode(LED_Y, OUTPUT);
  pinMode(LED_R, OUTPUT);
}

void loop()
{
  digitalWrite(LED_G, HIGH);
  digitalWrite(LED_Y, LOW);
  digitalWrite(LED_R, LOW);
  Serial.println("LED_G ON");
  delay(3000);

  digitalWrite(LED_G, LOW);
  digitalWrite(LED_Y, HIGH);
  digitalWrite(LED_R, LOW);
  Serial.println("LED_Y ON");
  delay(2000);

  digitalWrite(LED_G, LOW);
  digitalWrite(LED_Y, LOW);
  digitalWrite(LED_R, HIGH);
  Serial.println("LED_R ON");
  delay(1000);
}