Making an Internet Controlled LED

// Define the pins here, prefer PWM pins.
#define RED 6
#define GREEN 9
#define BLUE 10

#define MIN 0
#define MAX 255

int redVal = 0;
int greenVal = 0;
int blueVal = 0;
int brightnessStep = 25;  // This is how much the brightness changes for each event.

void setup() {
  Serial.begin(9600);
  pinMode(RED, OUTPUT);
  pinMode(GREEN, OUTPUT);
  pinMode(BLUE, OUTPUT);
}

void loop() {
  // A standard incoming serial packet normally contains two characters.
  // "ru" would stand for "red up". It can handle multiple incoming, i.e.
  // "rurururugugugugububububu" would run red green and blue up 3 times.
  if (Serial.available() >= 2) {
    for (int i = 0; i < 2; i++) {
      command[i] = Serial.read();
    }
    switch(command[1]) {
      case 'd':
        switch(command[0]) {
          case 'r':
            redDown();
            break;
          case 'g':
            greenDown();
            break;
          case 'b':
            blueDown();
            break;
        }
        break;
      case 'u':
        switch(command[0]) {
          case 'r':
            redDown();
            break;
          case 'g':
            greenDown();
            break;
          case 'b':
            blueDown();
            break;
        }
        break;
      default:
        break;
    }
  }
  
  analogWrite(RED, redVal);
  analogWrite(GREEN, greenVal);
  analogWrite(BLUE, blueVal);
  
  // Clear the buffer if there's some odd amount of data.
  // Ideally this should never happen.
  if (Serial.available() % 2 == 1) {
    Serial.end();
    Serial.begin(9600);
  }
}

void redUp() {
  redVal = threshold(redVal + brightnessStep);
}

void greenUp() {
  greenVal = threshold(greenVal + brightnessStep);
}

void blueUp() {
  blueVal = threshold(blueVal + brightnessStep);
}

void redDown() {
  redVal = threshold(blueVal - brightnessStep);
}

void greenDown() {
  greenVal = threshold(greenVal - brightnessStep);
}

void blueDown() {
  blueVal = threshold(greenVal - brightnessStep);
}

int threshold(int val) {
  if(val < MIN) {
    return MIN;
  } else if (val > MAX) {
    return MAX;
  }
  return val;
}