em410x.c

String sStart = "1111111110000000000";
String sStop = "0";
int data_to_spoof[64];
int coil_pin = 9; // we use 9th pin
int a,b,c,d;
unsigned long id;
char hex_code[8];

void setup()
{
  // Serial.begin(9600);
  pinMode(coil_pin, OUTPUT);
  digitalWrite(coil_pin, LOW);
  id = 0x503472;
  a=0;b=0;c=0;d=0;
  sprintf(hex_code, "%04X%04X",id);
  String s = sStart + em4x_code(hex_code[4]) + em4x_code(hex_code[5])
    + em4x_code(hex_code[6]) + em4x_code(hex_code[7]) + em4x_code(hex_code[0])
    + em4x_code(hex_code[1]) + em4x_code(hex_code[2]) + em4x_code(hex_code[3])
    + even_parity(a) + even_parity(b) + even_parity(c) + even_parity(d) + sStop;
  // Serial.println(s);
  to_code(s);
  loop();
}
 
void set_pin_manchester(int clock_half, int signal)
{
  int man_encoded = clock_half ^ signal;
  if(man_encoded == 1)
    {
      digitalWrite(coil_pin, HIGH);
    }
  else
    {
      digitalWrite(coil_pin, LOW);
    }
}
 
String em4x_code(char code)
{
  switch (code)
    {
    case '1':    d++; return "00011";
    case '2':    c++; return "00101";
    case '3':    c++;d++; return "00110";
    case '4':    b++; return "01001";
    case '5':    b++;d++; return "01010";
    case '6':    b++;c++; return "01100";
    case '7':    b++;c++;d++; return "01111";
    case '8':    a++; return "10001";
    case '9':    a++;d++; return "10010";
    case 'A':    a++;c++; return "10100";
    case 'B':    a++;c++;d++; return "10111";
    case 'C':    a++;b++; return "11000";
    case 'D':    a++;b++;d++; return "11011";        
    case 'E':    a++;b++;c++; return "11101";
    case 'F':    a++;b++;c++;d++; return "11110";
    }
  return "00000";
}

String even_parity(int p)
{
  if (p % 2)
    return "1";
  return "0";
}
 
void to_code(String s)
{
  for(int i = 0; i < 64; i++)
    {
      if (s[i]=='0'){data_to_spoof[i]=0;}else{data_to_spoof[i]=1;}
    }
}

void loop()
{
  for(int i = 0; i < 64; i++)
    {
      set_pin_manchester(0, data_to_spoof[i]);
      delayMicroseconds(256);
      set_pin_manchester(1, data_to_spoof[i]);
      delayMicroseconds(256);
    }
}