#include

LCD4Bit_mod lcd = LCD4Bit_mod(2);

char GP2D12;
char a,b;
char str1[]="Renge:";
char str2[]="   Renge Over   ";
char str3[]="cm";

void setup()
{
  lcd.init();
  lcd.clear();
  lcd.printIn("GP2D12 testing...");
}

void loop()
{
      GP2D12=read_gp2d12_range(1);
      if(GP2D12>80||GP2D12<10)
        {
          lcd.cursorTo(2,0);
          lcd.printIn(str2);     
        }
      else
        {
          a=0x30+GP2D12/10;
          b=0x30+GP2D12%10;          
          lcd.cursorTo(2, 3);
          lcd.printIn(str1);    
          lcd.print(a);    
          lcd.print(b);
          lcd.printIn(str3);                    
        }    
    delay(50);
}

float read_gp2d12_range(byte pin)
{
 int tmp;
 tmp = analogRead(pin);
 if (tmp < 3)return -1;
 return (6787.0 /((float)tmp - 3.0)) - 4.0;
}