KEYPAD WITHOUT LIBRARY

 

int c1 = 7, c2 = 6, c3 = 5, c4 = 4;

int r1 = 13, r2 = 12,r3 = 11, r4 = 10; 

void setup(){

  pinMode(c1, INPUT_PULLUP);

   pinMode(c2, INPUT_PULLUP);

   pinMode(c3, INPUT_PULLUP);

   pinMode(c4, INPUT_PULLUP);

   

  pinMode(r1, OUTPUT);

   pinMode(r2, OUTPUT);

  pinMode(r3, OUTPUT);

   pinMode(r4, OUTPUT);

  

  digitalWrite(r1, HIGH);

  digitalWrite(r2, HIGH);

  digitalWrite(r3, HIGH);

  digitalWrite(r4, HIGH);

  

  Serial.begin(38400);

}

void loop()

{

  row1();

  row2();

  row3();

  row4();

  //Serial.println(" Press any Key to see the value:");

}

void row1()

{

  digitalWrite(r1, LOW);

  digitalWrite(r2, HIGH);

  digitalWrite(r3, HIGH);

  digitalWrite(r4, HIGH);

  if(digitalRead(c1)== LOW){//pin 5

    Serial.println("1");

    delay(600);}

  else if(digitalRead(c2)== LOW){//pin 4

    Serial.println("2");

    delay(600);}

   else if(digitalRead(c3)== LOW){//pin 3

    Serial.println("3");

    delay(600);}

   else if(digitalRead(c4)== LOW){

    Serial.println("A");//pin 2

 

    delay(600);}

}

void row2(){

  digitalWrite(r1, HIGH);

  digitalWrite(r2, LOW);

  digitalWrite(r3, HIGH);

  digitalWrite(r4, HIGH);

  if(digitalRead(c1) == LOW) {

    Serial.println("4");

    delay(600);}

  else if(digitalRead(c2) == LOW) {

    Serial.println("5");

    delay(600); }

  else if(digitalRead(c3) == LOW) {

    Serial.println("6");

    delay(600);

  }

  else if(digitalRead(c4) == LOW) {

    Serial.println("B");

    delay(600);

  }

}

  

void row3(){

  digitalWrite(r1, HIGH);

  digitalWrite(r2, HIGH);

  digitalWrite(r3, LOW);

  digitalWrite(r4, HIGH);

  

  if(digitalRead(c1) == LOW){

    Serial.println("7");

    delay(600);}

  else if(digitalRead(c2) == LOW) {

    Serial.println("8");

    delay(600);}

  else if(digitalRead(c3) == LOW) {

    Serial.println("9");

    

    delay(600);}

  else if(digitalRead(c4) == LOW) {

    Serial.println("C");

    delay(600);}

}

void row4(){

  digitalWrite(r1, HIGH);

  digitalWrite(r2, HIGH);

  digitalWrite(r3, HIGH);

  digitalWrite(r4, LOW);

  if(digitalRead(c1) == LOW){

    Serial.println("*");

    delay(600);}

  else if(digitalRead(c2) == LOW) {

    Serial.println("0");

      delay(600); }

  else if(digitalRead(c3) == LOW) {

    Serial.println("#");

    delay(600); }

  else if(digitalRead(c4) == LOW) {

    Serial.println("D");

  delay(600);}

}