Ledpong : random with nodejs

ledpong_random.js

var SerialPort = require("serialport").SerialPort;
var serialPort;
try {
    serialPort = new SerialPort("/dev/ttyACM0", { baudrate: 38400 });
} catch(e) {
    console.error(e.stack);
    serialPort = { write: console.log };
}

setInterval(function() {
  var random = "Z";

  for(i=0; i<432; i++){
      var num = Math.random();
      if(num > 0.8){
        random += "F";
      } else if(num > 0.6){
        random += "A";
      } else if(num > 0.4){
        random += "6";
      } else if(num > 0.2){
        random += "3";
      } else {
        random += "0"
      }
  }
  serialPort.write(random);
}, 1);