I Should provide the complete code
const int RED_PIN = 9;
const int GREEN_PIN = 10;
const int BLUE_PIN = 11;
// This variable controls how fast we loop through the colors.
// (Try changing this to make the fading faster or slower.)
int DISPLAY_TIME = 100; // In milliseconds
void setup()
{
// Here we'll configure the Arduino pins we're using to
// drive the LED to be outputs:
pinMode(RED_PIN, OUTPUT);
pinMode(GREEN_PIN, OUTPUT);
pinMode(BLUE_PIN, OUTPUT);
}
void loop()
{
// In this sketch, we'll start writing our own functions.
// This makes the sketch easier to follow by dividing up
// the sketch into sections, and not having everything in
// setup() or loop().
// We'll show you two ways to run the RGB LED.
// The first way is to turn the individual LEDs (red, blue,
// and green) on and off in various combinations. This gives you
// a total of eight colors (if you count "black" as a color).
// We've written a function called mainColors() that steps
// through all eight of these colors. We're only "calling" the
// function here (telling it to run). The actual function code
// is further down in the sketch.
mainColors();
// The above function turns the individual LEDs full-on and
// full-off. If you want to generate more than eight colors,
// you can do so by varying the brightness of the individual
// LEDs between full-on and full-off.
// The analogWrite() function lets us do this. This function
// lets you dim a LED from full-off to full-on over 255 steps.
// We've written a function called showSpectrum() that smoothly
// steps through all the colors. Again we're just calling it
// here; the actual code is further down in this sketch.
showSpectrum();
}
// Here's the mainColors() function we've written.
// 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 cancopy and paste that section into your code.
void mainColors()
{
// Off (all LEDs off):
digitalWrite(RED_PIN, LOW);
digitalWrite(GREEN_PIN, LOW);
digitalWrite(BLUE_PIN, LOW);
delay(1000);
// Red (turn just the red LED on):
digitalWrite(RED_PIN, HIGH);
digitalWrite(GREEN_PIN, LOW);
digitalWrite(BLUE_PIN, LOW);
delay(1000);
// Green (turn just the green LED on):
digitalWrite(RED_PIN, LOW);
digitalWrite(GREEN_PIN, HIGH);
digitalWrite(BLUE_PIN, LOW);
delay(1000);
// Blue (turn just the blue LED on):
digitalWrite(RED_PIN, LOW);
digitalWrite(GREEN_PIN, LOW);
digitalWrite(BLUE_PIN, HIGH);
delay(1000);
// Yellow (turn red and green on):
digitalWrite(RED_PIN, HIGH);
digitalWrite(GREEN_PIN, HIGH);
digitalWrite(BLUE_PIN, LOW);
delay(1000);
// Cyan (turn green and blue on):
digitalWrite(RED_PIN, LOW);
digitalWrite(GREEN_PIN, HIGH);
digitalWrite(BLUE_PIN, HIGH);
delay(1000);
// Purple (turn red and blue on):
digitalWrite(RED_PIN, HIGH);
digitalWrite(GREEN_PIN, LOW);
digitalWrite(BLUE_PIN, HIGH);
delay(1000);
// White (turn all the LEDs on):
digitalWrite(RED_PIN, HIGH);
digitalWrite(GREEN_PIN, HIGH);
digitalWrite(BLUE_PIN, HIGH);
delay(1000);
}
// Below are two more functions we've written,
// showSpectrum() and showRGB().
// showRGB() displays a single color on the RGB LED.
// You call showRGB() with the number of a color you want
// to display.
// showSpectrum() steps through all the colors of the RGB LED,
// displaying a rainbow. showSpectrum() actually calls showRGB()
// over and over to do this.
// We'll often break tasks down into individual functions like
// this, which makes your sketches easier to follow, and once
// you have a handy function, you can reuse it in your other
// programs.
// showSpectrum()
// This function steps through all the colors of the RGB LED.
// It does this by stepping a variable from 0 to 768 (the total
// number of colors), and repeatedly calling showRGB() to display
// the individual colors.
// In this function, we're using a "for() loop" to step a variable
// from one value to another, and perform a set of instructions
// for each step. For() loops are a very handy way to get numbers
// to count up or down.
// Every for() loop has three statements separated by semicolons:
// 1. Something to do before starting
// 2. A test to perform; as long as it's true,
// it will keep looping
// 3. Something to do after each loop (usually
// increase a variable)
// For the for() loop below, these are the three statements:
// 1. x = 0; Before starting, make x = 0.
// 2. x < 768; While x is less than 768, run the
// following code.
// 3. x++ Putting "++" after a variable means
// "add one to it". (You can also use "x = x + 1")
// Every time you go through the loop, the statements following
// the loop (those within the brackets) will run.
// And when the test in statement 2 is finally false, the sketch
// will continue.
void showSpectrum()
{
int x; // define an integer variable called "x"
// Now we'll use a for() loop to make x count from 0 to 767
// (Note that there's no semicolon after this line!
// That's because the for() loop will repeat the next
// "statement", which in this case is everything within
// the following brackets {} )
for (x = 0; x < 768; x++)
// Each time we loop (with a new value of x), do the following:
{
showRGB(x); // Call RGBspectrum() with our new x
delay(10); // Delay for 10 ms (1/100th of a second)
}
}
// showRGB()
// 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.
// If you count up from 0 to 767 and pass that number to this
// function, the LED will smoothly fade between all the colors.
// (Because it starts and ends on pure red, you can start over
// at 0 without any break in the spectrum).
void showRGB(int color)
{
int redIntensity;
int greenIntensity;
int blueIntensity;
// Here we'll use an "if / else" statement to determine which
// of the three (R,G,B) zones x falls into. Each of these zones
// spans 255 because analogWrite() wants a number from 0 to 255.
// In each of these zones, we'll calculate the brightness
// for each of the red, green, and blue LEDs within the RGB LED.
if (color <= 255) // zone 1
{
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) // zone 2
{
redIntensity = 0; // red is always off
greenIntensity = 255 - (color - 256); // green on to off
blueIntensity = (color - 256); // blue off to on
}
else // color >= 512 // zone 3
{
redIntensity = (color - 512); // red off to on
greenIntensity = 0; // green is always off
blueIntensity = 255 - (color - 512); // blue on to off
}
// Now that the brightness values have been set, command the LED
// to those values
analogWrite(RED_PIN, redIntensity);
analogWrite(BLUE_PIN, blueIntensity);
analogWrite(GREEN_PIN, greenIntensity);
}
