The RGB.pd patch uses a tri-color LED to demonstrate the PWM (Analog out) mode of the Firmata firmware for the Arduino board.
The arduino patch has argument "4", which happens to be number my USB/comport has. You can find yours by sending the "devices" message to the arduino patch.
Of course, using a computer running Pd is a bit of overhead for an Arduino board controlling a tri-color LED, but it was fun to make and a nice demo :-).
Latest update: 2011-08-20email: firstname.lastname@example.org