/* selecting A-D selects the digit, automatically digit 4
once a number is pressed it becomes the number that is pressed
pressing '*' clears all digits and resets to digit 4
pressing '#' does nothing
*/

#include <Keypad.h> //keypad library by Mark Stanley and Alexander Brevig
#define A 2
#define B 3
#define C 4
#define D 5
#define E 14
#define F 15
#define G 16
#define D1 17
#define D2 18
#define D3 19
#define D4 20

char dig = D4;

const byte ROWS = 4; //four rows on the keypad
const byte COLS = 4; //four columns on the keypad
char hexaKeys[ROWS][COLS] = { //matrix that mimics the keypad
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};
byte rowPins[ROWS] = {10, 11, 12, 13}; //define the pins connected to each row
byte colPins[COLS] = {6, 7, 8, 9}; //define the pins connected to each column
Keypad customKeypad = Keypad( makeKeymap(hexaKeys), rowPins, colPins, ROWS, COLS); //create keypad object

void setup() {
  Serial.begin(9600); //start serial communication
  for (int i = 2; i < 6; i++) pinMode(i, OUTPUT);
  for (int i = 14; i < 17; i++) pinMode(i, OUTPUT);
  off(); //clear display
}

void loop() {
  char Key = customKeypad.getKey(); //read key that is pressed
  if (Key) { //if a key is pressed
    Serial.println(Key); //print the key in serial communication
    switch (Key) {
      case '0':
        dig_select();
        zero();
        break;
      case '1':
        dig_select();
        one();
        break;
      case '2':
        dig_select();
        two();
        break;
      case '3':
        dig_select();
        three();
        break;
      case '4':
        dig_select();
        four();
        break;
      case '5':
        dig_select();
        five();
        break;
      case '6':
        dig_select();
        six();
        break;
      case '7':
        dig_select();
        seven();
        break;
      case '8':
        dig_select();
        eight();
        break;
      case '9':
        dig_select();
        nine();
        break;
      case 'A':
        dig = D1;
        break;
      case 'B':
        dig = D2;
        break;
      case 'C':
        dig = D3;
        break;
      case 'D':
        dig = D4;
        break;
      case '*':
        for (int i = 17; i < 21; i++){
          digitalWrite(i,HIGH);
        }
        off();
        dig = D4;
        dig_select();
        break;
    }
  }

}

void off() {
  digitalWrite(A, HIGH);
  digitalWrite(B, HIGH);
  digitalWrite(C, HIGH);
  digitalWrite(D, HIGH);
  digitalWrite(E, HIGH);
  digitalWrite(F, HIGH);
  digitalWrite(G, HIGH);
}

void one() {
  digitalWrite(A, HIGH);
  digitalWrite(B, LOW);
  digitalWrite(C, LOW);
  digitalWrite(D, HIGH);
  digitalWrite(E, HIGH);
  digitalWrite(F, HIGH);
  digitalWrite(G, HIGH);
}

void two() {
  digitalWrite(A, LOW);
  digitalWrite(B, LOW);
  digitalWrite(C, HIGH);
  digitalWrite(D, LOW);
  digitalWrite(E, LOW);
  digitalWrite(F, HIGH);
  digitalWrite(G, LOW);
}

void three() {
  digitalWrite(A, LOW);
  digitalWrite(B, LOW);
  digitalWrite(C, LOW);
  digitalWrite(D, LOW);
  digitalWrite(E, HIGH);
  digitalWrite(F, HIGH);
  digitalWrite(G, LOW);
}

void four() {
  digitalWrite(A, HIGH);
  digitalWrite(B, LOW);
  digitalWrite(C, LOW);
  digitalWrite(D, HIGH);
  digitalWrite(E, HIGH);
  digitalWrite(F, LOW);
  digitalWrite(G, LOW);
}

void five() {
  digitalWrite(A, LOW);
  digitalWrite(B, HIGH);
  digitalWrite(C, LOW);
  digitalWrite(D, LOW);
  digitalWrite(E, HIGH);
  digitalWrite(F, LOW);
  digitalWrite(G, LOW);
}

void six() {
  digitalWrite(A, LOW);
  digitalWrite(B, HIGH);
  digitalWrite(C, LOW);
  digitalWrite(D, LOW);
  digitalWrite(E, LOW);
  digitalWrite(F, LOW);
  digitalWrite(G, LOW);
}

void seven() {
  digitalWrite(A, LOW);
  digitalWrite(B, LOW);
  digitalWrite(C, LOW);
  digitalWrite(D, HIGH);
  digitalWrite(E, HIGH);
  digitalWrite(F, HIGH);
  digitalWrite(G, HIGH);
}

void eight() {
  digitalWrite(A, LOW);
  digitalWrite(B, LOW);
  digitalWrite(C, LOW);
  digitalWrite(D, LOW);
  digitalWrite(E, LOW);
  digitalWrite(F, LOW);
  digitalWrite(G, LOW);
}

void nine() {
  digitalWrite(A, LOW);
  digitalWrite(B, LOW);
  digitalWrite(C, LOW);
  digitalWrite(D, LOW);
  digitalWrite(E, HIGH);
  digitalWrite(F, LOW);
  digitalWrite(G, LOW);
}

void zero() {
  digitalWrite(A, LOW);
  digitalWrite(B, LOW);
  digitalWrite(C, LOW);
  digitalWrite(D, LOW);
  digitalWrite(E, LOW);
  digitalWrite(F, LOW);
  digitalWrite(G, HIGH);
}

void printA() {
  digitalWrite(A, LOW);
  digitalWrite(B, LOW);
  digitalWrite(C, LOW);
  digitalWrite(D, HIGH);
  digitalWrite(E, LOW);
  digitalWrite(F, LOW);
  digitalWrite(G, LOW);
}


void printC() {
  digitalWrite(A, LOW);
  digitalWrite(B, HIGH);
  digitalWrite(C, HIGH);
  digitalWrite(D, LOW);
  digitalWrite(E, LOW);
  digitalWrite(F, LOW);
  digitalWrite(G, HIGH);
}

void dig_select() {
  for (int i = 17; i < 21; i++) {
    digitalWrite(i, LOW); //turn all digits off
  }
  digitalWrite(dig, HIGH); //turn current dig on
}