Move your mouse to the right in the processing sketch, the LED gets bright. Move it to the left, it gets darker. Genius. Also the background in processing gets brighter and darker along with the LED. I thought that was fun. PROCESSING CODE: import processing.serial.*; //import all serial libraries Serial serPort; // Create object from Serial class void setup() { size(600, 150); serPort = new Serial(this, Serial.list()[0], 9600); } void draw() { int briteness = int(map(mouseX, 0, 600, 0, 255)); //set variable relative to mouse X serPort.write(briteness); //write value to serial background(0, briteness, 0); //set background green to value delay(50); //delay 50 ms so arduino can catch up } ARDUINO CODE: const int led1 = 9; int brightness; void setup() { Serial.begin(9600); } void loop() { if (Serial.available() > 0) { //check if serial isn't empty brightness = Serial.read(); //set varible to last byte in serial analogWrite(led1, brightness); //write value to LED } delay(50); }  |