   attachCommandCallbacks();
 
   // Send the status to the PC that says the Arduino has booted
-  cmdMessenger.sendCmd(kAcknowledge,"Arduino has started!");
+  // Note that this is a good debug function: it will let you also know 
+  // if your program had a bug and the arduino restarted  
+  cmdMessenger.sendCmd(kStatus,"Arduino has started!");
 
   // set pin for blink LED
   pinMode(kBlinkLed, OUTPUT);
-}
-
-// Returns if it has been more than interval (in ms) ago. Used for periodic actions
-bool hasExpired(unsigned long &prevTime, unsigned long interval) {
-  if (  millis() - prevTime > interval ) {
-    prevTime = millis();
-    return true;
-  } else     
-    return false;
 }
 
 // Loop function

{
  // Process incoming serial data, and perform callbacks
  cmdMessenger.feedinSerialData();

  // Toggle LED periodically. If the LED does not toggle every 2000 ms, 
  // this means that cmdMessenger are taking a longer time than this  
  if (hasExpired(previousToggleLed,2000)) // Toggle every 2 secs
  {
    toggleLed();  
  } 
}

// Toggle led state 
void toggleLed()
{  
  ledState = !ledState;
  digitalWrite(kBlinkLed, ledState?HIGH:LOW);
}  

// In order to receive, attach a callback function to these events
enum
{
  kSetLed              , // Command to request led to be set in specific state
  kStatus              , // Command to report status
};

// Callbacks define on which received commands we take action
void attachCommandCallbacks()
{
  // Attach callback methods
  cmdMessenger.attach(OnUnknownCommand);
  cmdMessenger.attach(kSetLed, OnSetLed);
}

// Called when a received command has no attached function
void OnUnknownCommand()
{
  cmdMessenger.sendCmd(kStatus,"Command without attached callback");
}

// Callback function that sets led on or off
void OnSetLed()
{
  // Read led state argument, interpret string as boolean
  ledState = cmdMessenger.readBoolArg();
  // Set led
  digitalWrite(kBlinkLed, ledState?HIGH:LOW);
  // Send back status that describes the led state
  cmdMessenger.sendCmd(kStatus,(int)ledState);
}

// Setup function
void setup() 
{
  // Listen on serial connection for messages from the PC
  Serial.begin(115200); 

  // Adds newline to every command
