Untitled

//define the matrix, X,Y values for each button
char key[4][4]={{'1','2','3','A'},{'4','5','6','B'},{'7','8','9','C'},{'*','0','#','D'}};
//define the pins for the keypad
#define pin1 23 
#define pin2 25
#define pin3 27  
#define pin4 29 
#define pin5 31  
#define pin6 33
#define pin7 35 
#define pin8 37  
//create new char variable for the value from keypad
char Pressed;
//define which pins of keypad are inputs and outputs
int input_pins[4]={8,7,6,5};
int output_pins[4]={13,12,10,9};
char digit = '0';

char mykey(void)
{
  int r,c;            //integers for row and colum

  for(r=0;r<4;r++)    //define the course of the loop, from row 0 to row 3
  {
    digitalWrite(output_pins[r],LOW);     //send 0 to all output pins
    for(int c=0;c<4;c++)                  
    { 
    if((digitalRead(input_pins[c])==LOW)) //check for the right colum
    return key[r][c];
    }
    digitalWrite(output_pins[r],HIGH);    // send 1 to the right output pin
  }
  return '$';                             //return value for unpressed
  }
  
void setup() 
{
 Serial.begin(9600);                      
  pinMode(pin1,INPUT_PULLUP);             //define which pin is input and which is output
  pinMode(pin2,INPUT_PULLUP);             //define which pin is input and which is output
  pinMode(pin3,INPUT_PULLUP);             //define which pin is input and which is output
  pinMode(pin4,INPUT_PULLUP);             //define which pin is input and which is output
  pinMode(pin5,OUTPUT);             //define which pin is input and which is output
  pinMode(pin6,OUTPUT);             //define which pin is input and which is output
  pinMode(pin7,OUTPUT);             //define which pin is input and which is output
  pinMode(pin8,OUTPUT);             //define which pin is input and which is output
  digitalWrite(pin5,HIGH);          //start outputs from 1
  digitalWrite(pin6,HIGH);          //start outputs from 1
  digitalWrite(pin7,HIGH);          //start outputs from 1
  digitalWrite(pin8,HIGH);          //start outputs from 1
#define A 53         // define the parts of the digit to specific pins
#define B 51
#define C 49
#define D 47
#define E 45
#define F 41
#define G 39
pinMode(A, OUTPUT);   //define pins as outputs
pinMode(B, OUTPUT);
pinMode(C, OUTPUT);
pinMode(D, OUTPUT);
pinMode(E, OUTPUT);
pinMode(F, OUTPUT);
pinMode(G, OUTPUT);
}

void loop() 
{
  Pressed=mykey();
  if(Pressed!='$')                  //if pressed
  {
    Serial.println(Pressed);        //prints the pressed value
  }
  delay(200);                         //delay to get the value from the keypad once and not multiple times for one press
  digit = Pressed;
  switch(digit)
  { 
    default:
    digitalWrite(A,LOW);
    digitalWrite(B,HIGH);
    digitalWrite(C,HIGH);
    digitalWrite(D,LOW);
    digitalWrite(E,HIGH);
    digitalWrite(F,HIGH);
    digitalWrite(G,HIGH);
    break;

    case(0):               //Define which parts of screen to turn on for each digit
    digitalWrite(A,LOW);
    digitalWrite(B,LOW);
    digitalWrite(C,LOW);
    digitalWrite(D,LOW);
    digitalWrite(E,LOW);
    digitalWrite(F,LOW);
    digitalWrite(G,HIGH);
    break;

    case('1'):                //Define which parts of screen to turn on for each digit
    digitalWrite(A,HIGH);
    digitalWrite(B,LOW);
    digitalWrite(C,LOW);
    digitalWrite(D,HIGH);
    digitalWrite(E,HIGH);
    digitalWrite(F,HIGH);
    digitalWrite(G,HIGH);
    break;
    
    case('2'):              //Define which parts of screen to turn on for each digit
    digitalWrite(A,LOW);
    digitalWrite(B,LOW);
    digitalWrite(C,HIGH);
    digitalWrite(D,LOW);
    digitalWrite(E,LOW);
    digitalWrite(F,HIGH);
    digitalWrite(G,LOW);
    break;

    case('3'):              //Define which parts of screen to turn on for each digit
    digitalWrite(A,LOW);
    digitalWrite(B,LOW);
    digitalWrite(C,LOW);
    digitalWrite(D,LOW);
    digitalWrite(E,HIGH);
    digitalWrite(F,HIGH);
    digitalWrite(G,LOW);
    break;

    case('4'):              //Define which parts of screen to turn on for each digit
    digitalWrite(A,HIGH);
    digitalWrite(B,LOW);
    digitalWrite(C,LOW);
    digitalWrite(D,HIGH);
    digitalWrite(E,HIGH);
    digitalWrite(F,LOW);
    digitalWrite(G,LOW);
    break;

    case ('5'):              //Define which parts of screen to turn on for each digit
    digitalWrite(A,LOW);
    digitalWrite(B,HIGH);
    digitalWrite(C,LOW);
    digitalWrite(D,LOW);
    digitalWrite(E,HIGH);
    digitalWrite(F,LOW);
    digitalWrite(G,LOW);
    break;

    case ('6'):              //Define which parts of screen to turn on for each digit
    digitalWrite(A,LOW);
    digitalWrite(B,HIGH);
    digitalWrite(C,LOW);
    digitalWrite(D,LOW);
    digitalWrite(E,LOW);
    digitalWrite(F,LOW);
    digitalWrite(G,LOW);
    break;

    case ('7'):              //Define which parts of screen to turn on for each digit
    digitalWrite(A,LOW);
    digitalWrite(B,LOW);
    digitalWrite(C,LOW);
    digitalWrite(D,HIGH);
    digitalWrite(E,HIGH);
    digitalWrite(F,HIGH);
    digitalWrite(G,HIGH);
    break;

    case ('8'):              //Define which parts of screen to turn on for each digit
    digitalWrite(A,LOW);
    digitalWrite(B,LOW);
    digitalWrite(C,LOW);
    digitalWrite(D,LOW);
    digitalWrite(E,LOW);
    digitalWrite(F,LOW);
    digitalWrite(G,LOW);
    break;

    case ('9'):              //Define which parts of screen to turn on for each digit
    digitalWrite(A,LOW);
    digitalWrite(B,LOW);
    digitalWrite(C,LOW);
    digitalWrite(D,HIGH);
    digitalWrite(E,HIGH);
    digitalWrite(F,LOW);
    digitalWrite(G,LOW);
    break;
  }
}