[ruby+ardunio]twitterのリプライをarduinoのLEDで通知する

ardunioSide.c

int incomingByte = 0;
int ledPin = 13; //ardunioのLEDは13番ピン

void setup() {
  Serial.begin(9600);
  pinMode(ledPin, OUTPUT);
}

void loop() {
  if (Serial.available() > 0) {
    incomingByte = Serial.read();
    for(int i= 0; i< (incomingByte - 48); i++ )
    {
      digitalWrite(ledPin, HIGH);
      delay(500);
      digitalWrite(ledPin, LOW);
      delay(500);
    }
  }
}

rubySide.rb

require 'rubygems'
require 'serialport'
require 'twitter'
require 'pp'
require 'date'

Twitter.configure do |config|
  config.consumer_key = 'hoge'
  config.consumer_secret = 'hoge'
  config.oauth_token = 'hoge'
  config.oauth_token_secret = 'hoge'
end 

men = Twitter.mentions
port = "/dev/cu.usbmodemfd121"

open("twitid.txt") {|id|
    LASTID = id.readlines.first.to_i
}

sp = SerialPort.new(port, 9600, 8, 1, SerialPort::NONE)

if LASTID != men.last.id
  print "new mention \n"

  f = File.open("twitid.txt",'w')
  f.print men.last.id.to_s
  f.close

  start = Time.now.sec
  now = start
  while true 
    line = '9'
    sp.putc line
    sleep(1)
    now = Time.now.sec
    break if now > start+5
  end
end

sp.close