#include <Keypad.h>
const int ledPin = 4; 
int count = 0;
const uint8_t ROWS = 4;
const uint8_t COLS = 4;

char keys[ROWS][COLS] = {
  { '1', '2', '3', '%' },
  { '4', '5', '6', '@' },
  { '7', '8', '9', '$' },
  { '*', '0', '#', '!' }
};

uint8_t colPins[COLS] = { A1, A0, D8, D7 }; // Pins connected to C1, C2, C3, C4
uint8_t rowPins[ROWS] = { A5, A4, A3, A2  }; // Pins connected to R1, R2, R3, R4

Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

void setup() {
  pinMode(ledPin, OUTPUT);
  Serial.begin(9600);

}

void loop(){
  char key = keypad.getKey();
  if (key != NO_KEY) {
    Serial.println(key);
  }
  if (key == '%'){
    count += 1;
    if(count % 2 == 0){
      digitalWrite(ledPin, LOW);
      Serial.println("turning off");
    }else{
      digitalWrite(ledPin, HIGH);
      Serial.println("turning on");
    }
  }
  
  
  
}