If the Arduino interface (IDE) gets into a state where it can't download into
the Arduino (for whatever reason), or Putty doesn't print stuff out at all or
like a normal startup.
1) Turn the battery off.
2) Kill the Arduino interface (IDE) or Putty.
3) Unplug the Arduino USB cable from your computer (unplug the big connector
   (male A), not the micro USB connector on the Arduino. There is a chance
   the micro USB connector fails or breaks.).
4) Count to 10 (1 Mississippi, 2 Mississippi, ..., 10 Mississippi will take
about 10 seconds).
5) Plug the Arduino USB cable into your computer.
6) Restart the Arduino interface (IDE) or Putty.
7) Turn the battery on.

Common Errors:
1) avrdude: ser_open(): can't open device "/dev/ttyUSB0": No such file or
directory
-> USB cable to arduino not plugged in. -> plug it in
-or-
-> system switched to /dev/ttyUSB1 -> Set the port to /dev/ttyUSB1

2) avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 10 of 10: not in sync: resp=0x00
-> Do the first procedure above (kill, unplug, count, plug, restart).

