Starting sketch before connection to pc

Hi,

I'm trying to make an arduino uno output times to serial, sort of a external stopwatch,
and I have managed to do this. But I was wondering if it is possible to start the sketch,
and the timing, before I connect the arduino to the pc, so that I can start in one place,
and then move to the "finish line", without having to move the computer also.

Is it possible, and if yes, how?

Thanks

You need two things.

  1. To power the arduino. This can be done by batteries and will start a sketch running.
  2. To disable the auto reset that resets the arduino when ever the serial port is enabled. There is a link on the board you can cut to do this.

Where can I find the link I would need to cut?

Thank you very much for the reply :smiley:

Depends on what you have. This link shows you haw for some versions:-
http://www.arduino.cc/playground/Main/DisablingAutoResetOnSerialConnection

On the uno it is a pad to the left of the resistor pack marked reset close to pin 14 of the ATmega chip, slice the thin wire in between and add a solder blob to reconnect.

Thank you so much for all your help! :slight_smile: