arduinoprojects.com

This is a page I found extremely useful for calculating my resistors in LED circuits. You choose the number of LED's and the availiable source voltage and the program helps design the circuit for you. The nice thing about this page is that it also draws a sketch of the circuit* to build as a byproduct of the calculation:

(* be sure to click "wiring diagram")

http://led.linear1.org/led.wiz

To use the Wizard it might help to have the following data in lieu of the actual specifications of your LED's:

here's a table to help you make decent guesses:

Hi everyone! One one of the useful things, especially if you have many boards that you regularly experiment with is to have some cheat sheets, ideally attached or close to your regular board. The reason is that in many cases one forgets the driving voltages an so on and might make toast out of an expensive board. I have these two texts on stickers behind the plastic boards I have made to hold my Arduinos:

Arduino Diecimilla
The power source is selected by the jumper between the USB and power plugs. To power the board from the USB port (good