RGB

หลักการทำงาน
เมื่อ RGB รับค่าจากArduinoแล้ว ก็จะไปแสดงแบบผสมสี หากมีไฟเข้ามากกว่า1สี

Code
const int RED_PIN = 9;
const int GREEN_PIN = 10;
const int BLUE_PIN = 11;
const int DISPLAY_TIME = 1000;  // used in mainColors() to determine the
// length of time each color is displayed.
void setup() //Configure the Arduino pins to be outputs to drive the LEDs
{
  pinMode(RED_PIN, OUTPUT);
  pinMode(GREEN_PIN, OUTPUT);
  pinMode(BLUE_PIN, OUTPUT);
}
void loop()
{
  mainColors();        // Red, Green, Blue, Yellow, Cyan, Purple, White
  //  showSpectrum();    // Gradual fade from Red to Green to Blue to Red
}
/******************************************************************
 * void mainColors()
 * This function displays the eight "main" colors that the RGB LED
 * can produce. If you'd like to use one of these colors in your
 * own sketch, you can copy and paste that section into your code.
/*****************************************************************/
void mainColors()
{
  // all LEDs off
  digitalWrite(RED_PIN, LOW);
  digitalWrite(GREEN_PIN, LOW);
  digitalWrite(BLUE_PIN, LOW);
  delay(DISPLAY_TIME);
  // Red
  digitalWrite(RED_PIN, HIGH);
  digitalWrite(GREEN_PIN, LOW);
  digitalWrite(BLUE_PIN, LOW);
  delay(DISPLAY_TIME);
  // Green
  digitalWrite(RED_PIN, LOW);
  digitalWrite(GREEN_PIN, HIGH);
  digitalWrite(BLUE_PIN, LOW);
  delay(DISPLAY_TIME);
  // Blue
  digitalWrite(RED_PIN, LOW);
  digitalWrite(GREEN_PIN, LOW);
  digitalWrite(BLUE_PIN, HIGH);
  delay(DISPLAY_TIME);
  // Yellow (Red and Green)
  digitalWrite(RED_PIN, HIGH);
  digitalWrite(GREEN_PIN, HIGH);
  digitalWrite(BLUE_PIN, LOW);
  delay(DISPLAY_TIME);
  // Cyan (Green and Blue)
  digitalWrite(RED_PIN, LOW);
  digitalWrite(GREEN_PIN, HIGH);
  digitalWrite(BLUE_PIN, HIGH);
  delay(DISPLAY_TIME);
  // Purple (Red and Blue)
  digitalWrite(RED_PIN, HIGH);
  digitalWrite(GREEN_PIN, LOW);
  digitalWrite(BLUE_PIN, HIGH);
  delay(DISPLAY_TIME);
  // White (turn all the LEDs on)
  digitalWrite(RED_PIN, HIGH);
  digitalWrite(GREEN_PIN, HIGH);
  digitalWrite(BLUE_PIN, HIGH);
  delay(DISPLAY_TIME);
}
/******************************************************************
 * void showSpectrum()
 *
 * Steps through all the colors of the RGB LED, displaying a rainbow.
 * showSpectrum() calls a function RGB(int color) that translates a number
 * from 0 to 767 where 0 = all RED, 767 = all RED
 * 
 * Breaking down tasks down into individual functions like this
 * makes your code easier to follow, and it allows.
 * parts of your code to be re-used.
/*****************************************************************/
void showSpectrum()
{
  for (int x = 0; x <= 767; x++)
  {
    RGB(x);      // Increment x and call RGB() to progress through colors.
    delay(10);   // Delay for 10 ms (1/100th of a second) - to help the "smoothing"
  }
}
/******************************************************************
 * void RGB(int color)
 *
 * RGB(###) displays a single color on the RGB LED.
 * Call RGB(###) with the number of a color you want
 * to display. For example, RGB(0) displays pure RED, RGB(255)
 * displays pure green.
 *
 * This function translates a number between 0 and 767 into a
 * specific color on the RGB LED. If you have this number count
 * through the whole range (0 to 767), the LED will smoothly
 * change color through the entire spectrum.
 *
 * The "base" numbers are:
 * 0   = pure red
 * 255 = pure green
 * 511 = pure blue
 * 767 = pure red (again)
 *
 * Numbers between the above colors will create blends. For
 * example, 640 is midway between 512 (pure blue) and 767
 * (pure red). It will give you a 50/50 mix of blue and red,
 * resulting in purple.
/*****************************************************************/
void RGB(int color)
{
  int redIntensity;
  int greenIntensity;
  int blueIntensity;
  color = constrain(color, 0, 767); // constrain the input value to a range of values from 0 to 767
    // if statement breaks down the "color" into three ranges:
  if (color <= 255)       // RANGE 1 (0 - 255) - red to green
  {
    redIntensity = 255 - color;    // red goes from on to off
    greenIntensity = color;        // green goes from off to on
    blueIntensity = 0;             // blue is always off
  }
  else if (color <= 511)  // RANGE 2 (256 - 511) - green to blue
  {
    redIntensity = 0;                     // red is always off
    greenIntensity = 511 - color;         // green on to off
    blueIntensity = color - 256;          // blue off to on
  }
  else                    // RANGE 3 ( >= 512)- blue to red
  {
    redIntensity = color - 512;         // red off to on
    greenIntensity = 0;                 // green is always off
    blueIntensity = 767 - color;        // blue on to off
  }
  // "send" intensity values to the Red, Green, Blue Pins using analogWrite()
  analogWrite(RED_PIN, redIntensity);
  analogWrite(GREEN_PIN, greenIntensity);
  analogWrite(BLUE_PIN, blueIntensity);
}