this is a simple shield that you don't need to make (you can just put and led into your arduino or use the built in one)and will create and flashing sequence you so desire.

You simply assemble the shield with a 220 ohm resistor and use it to flash any signal you like or even just to make your arduino look better in a display box etc... This board is NOT necessary in any way and I don't suggest you get it made. The code is for SOS and is appropriately timed to these specifications; a dash is three times as long as a dot, the time between each dash or dot is as long as a dot, the space, the space between two letters is the same length as a dash, and the space between a word is the same as seven dots.