/*Author: BehindTheSciences.com */
#include <SoftwareSerial.h>// import the serial library
#include <LiquidCrystal.h>
#define trigPin 5
#define echoPin 6
#define RS 12
#define RW 2
#define EN 11
#define VO 13
#define D4 7
#define D5 8
#define D6 9
#define D7 10
SoftwareSerial ser(3, 4); // RX, TX
int i = 1;
// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(12, 11, 7, 8, 9, 10);
 
void setup() {
  // Run Once Setup code
  ser.begin(9600);
  Serial.begin(9600);
  pinMode(A0, OUTPUT);
  pinMode(A1, OUTPUT);
  pinMode(A2, OUTPUT);
  pinMode(A3, OUTPUT);
  pinMode(A4, INPUT);
  pinMode(A5, INPUT);
  pinMode(A6, INPUT);
  pinMode(A7, INPUT);
  /*Initialisation of the LCD */
  pinMode(D4, OUTPUT);
  pinMode(D5, OUTPUT);
  pinMode(D6, OUTPUT);
  pinMode(D7, OUTPUT);
  pinMode(EN, OUTPUT); 
  digitalWrite(EN, HIGH);
  pinMode(RS, OUTPUT); 
  digitalWrite(RS, LOW);
  pinMode(VO, OUTPUT); 
  digitalWrite(VO, LOW);
  pinMode(RW, OUTPUT); 
  digitalWrite(RW, LOW);
  delay(20); 
  digitalWrite(D7, LOW);
  digitalWrite(D6, LOW);
  digitalWrite(D5, HIGH);
  digitalWrite(D4, HIGH);
  delay(10);
  digitalWrite(D7, LOW);
  digitalWrite(D6, LOW);
  digitalWrite(D5, HIGH);
  digitalWrite(D4, LOW);
  digitalWrite(D7, LOW);
  digitalWrite(D6, LOW);
  digitalWrite(D5, HIGH);
  digitalWrite(D4, LOW);
  digitalWrite(D7, HIGH);
  digitalWrite(D6, HIGH);
  digitalWrite(D7, LOW);
  digitalWrite(D6, LOW);
  digitalWrite(D5, LOW);
  digitalWrite(D4, LOW);
  digitalWrite(D7, HIGH);
  digitalWrite(D6, LOW);
  digitalWrite(D5, LOW);
  digitalWrite(D4, LOW);
  digitalWrite(D7, LOW);
  digitalWrite(D6, LOW);
  digitalWrite(D5, LOW);
  digitalWrite(D4, LOW);
  digitalWrite(D7, LOW);
  digitalWrite(D6, LOW);
  digitalWrite(D5, LOW);
  digitalWrite(D4, HIGH);
  digitalWrite(D7, LOW);
  digitalWrite(D6, LOW);
  digitalWrite(D5, LOW);
  digitalWrite(D4, LOW);
  digitalWrite(D7, LOW);
  digitalWrite(D6, HIGH);
  digitalWrite(D5, HIGH);
  digitalWrite(D4, HIGH);
/*-----------------------*/
 lcd.begin(16, 2);
  // Print a message to the LCD.
  lcd.setCursor(3, 0);
  lcd.print("Behind The");
  lcd.setCursor(4, 1);
  lcd.print("Sciences");
  delay(3000);
  lcd.clear();
  lcd.setCursor(1, 0);
  lcd.print("Key Pressed:");
   }
 
void loop() {
  
 lcd.setCursor(i, 1);
 int key = getinp(); //Get key press if any
 if (key!=0xff) //if a key was pressed
 {
  i = i + 1; //index used to move the LCD cursor by 1.
  if (key == 15)
  {
    lcd.clear();
    lcd.setCursor(1, 0);
    lcd.print("Key Pressed:");
    i = 1;
  }
  else
  {
    lcd.print(key); //Print the pressed key
    delay(100);
  }
 }
  delay(100);
}

/*Function to scan matrix keypad for key presses*/  
int getKey()
{
  int c =0xFF;    
  /*Set all columns to low */
  digitalWrite(A0,HIGH);
  digitalWrite(A1,HIGH);
  digitalWrite(A2,HIGH);
  digitalWrite(A3,HIGH);
  /*Set Column 4 to low */
  digitalWrite(A0,LOW); //C4
  /*Read all rows one by one */
  if(analogRead(A4)== LOW) c=0x0D; //R4
  if(analogRead(A5)== LOW) c=0x0C; //R3
  if(analogRead(A6)== LOW) c=0x0B; //R2
  if(analogRead(A7)== LOW) c=0x0A; //R1
  /*Set Column 3 to low */
  digitalWrite(A0,HIGH); //C4
  digitalWrite(A1,LOW); //C3
  /*Read all rows one by one */
  if(analogRead(A4)== LOW) c=0x0E; //R4
  if(analogRead(A5)== LOW) c=9; //R3
  if(analogRead(A6)== LOW) c=6; //R2
  if(analogRead(A7)== LOW) c=3; //R1
  /*Set Column 2 to low */
  digitalWrite(A1,HIGH); //C3
  digitalWrite(A2,LOW); //C2
  /*Read all rows one by one */
  if(analogRead(A4)== LOW) c=0; //R4
  if(analogRead(A5)== LOW) c=8; //R3
  if(analogRead(A6)== LOW) c=5; //R2
  if(analogRead(A7)== LOW) c=2; //R1
  /*Set Column 1 to low */
  digitalWrite(A2,HIGH); //C2
  digitalWrite(A3,LOW); //C1
  /*Read all rows one by one */
  if(analogRead(A4)== LOW) c=15; //R4
  if(analogRead(A5)== LOW) c=7; //R3
  if(analogRead(A6)== LOW) c=4; //R2
  if(analogRead(A7)== LOW) c=1; //R1

return c;
}
/*Function to get input key pressed*/
int getinp()
{
  int n;     //value to store key press
  int d;    //value used to temporarily store keypress

  n = 0xFF;

while (n == 0xFF) //waits for keypress
{ 

  n = getKey();       //Accessing the getKey() function
  d = n;        //give value of key pressed to d

  while (d != 0xFF)       //loop waits for the user to release the button
{
  d = getKey();     // Scans keypad for a keypress
}

delay(300);          // debouncing time

}
return n;         //return value of key pressed
}