Piggy Bank code

//Piggy Bank code by mizzuddinkamal

// include the library code:
#include <LiquidCrystal.h>
#include <Wire.h>

// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);

// include the library code:
#include <LiquidCrystal.h>

// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(7,8,9,10,11,12);

volatile byte CoinPulseCount = 0;
byte NewCoinInserted;
byte Command = 0;
int OpticalCountPin = 3;
volatile unsigned long PulseTime;
float CurrentCredit;
float NewCurrentCredit;

String OnePulse = "50 Sen";
String TwoPulses = "50 Sen";
String ThreePulses = "20 Sen";
String FourPulses = "20 Sen";
String FivePulses = "£1";
String SixPulses = "£2";

void showCredit(){
  NewCurrentCredit = (CurrentCredit/100) + NewCurrentCredit;
  Serial.print("Total Credit: RM ");
  Serial.println(NewCurrentCredit);
  lcd.begin(16,2);
  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print("Total Credit: RM");
  lcd.setCursor(0,1);
  lcd.print(NewCurrentCredit);
}

void setup(){
  Serial.begin(9600);
  Serial.println("Waiting...");
  Serial.println();
  pinMode(OpticalCountPin, INPUT);
  attachInterrupt(1, CoinPulse, RISING);
  lcd.setCursor(0,0);
  lcd.print("Waiting. . .");
}

void loop(){
  if(CoinPulseCount > 0 && millis() - PulseTime > 200){
    NewCoinInserted = CoinPulseCount;
    CoinPulseCount = 0;
  }
        switch(NewCoinInserted){
          case 1:
            Serial.println(OnePulse + " inserted");
            CurrentCredit = 50;
            showCredit();
            NewCoinInserted = 0;
            break;
          case 2:
            Serial.println(TwoPulses + " inserted");
            CurrentCredit = 50;
            showCredit();
            NewCoinInserted = 0;
            break;
          case 3:
            Serial.println(ThreePulses + " inserted");
            CurrentCredit = 20;
            showCredit();
            NewCoinInserted = 0;
            break;
          case 4:
            Serial.println(FourPulses + " inserted");
            CurrentCredit = 20;
            showCredit();
            NewCoinInserted = 0;
            break;
          case 5:
            Serial.println(FivePulses + " inserted");
            NewCoinInserted = 0;
            break;
          case 6:
            Serial.println(SixPulses + " inserted");
            NewCoinInserted = 0;
            break;
        }
}

void CoinPulse(){
  CoinPulseCount ++;
  PulseTime = millis();
}