title: python detecting usb ports when they are turned on and starting a thread
body: <p>Okay, I would like to upgrade my code for detecting ports and starting a thread once the port is available.  What I am currently doing is waiting for the expected number of ports to be there.  then I do a for loop to start the Thread.  Like I said, Currently I do a </p>
  
  <pre><code>subprocess.check_output('ls /tty' + number expected port) #to see if all ports are turned on. 
  
  for port in portlist: 
      initialize the Thread object.
  </code></pre>
  
  <p>The problem is that the code that I have on the USB devices I have only 10 seconds to write to the device to tell it is in command mode.  So if I have like 10 devices that I want to program, if I don't turn them all on really fast, I won't be able to program the first couple of devices due to the fact that I am waiting to see all ports turned on...  Changing the time on the USB devices CANNOT BE CHANGED.</p>
  
  <p>I would like to see the new port and then start the thread.  Can anyone help.  I hope I explained this well enough.  This is on a linux machine so the ports are assigned as they are turned on.</p>