/* * Code for cross-fading 3 LEDs, red, green and blue (RGB) * To create fades, you need to do two things: * 1. Describe the colors you want to be displayed * 2. List the order you want them to fade in * * DESCRIBING A COLOR: * A color is just an array of three percentages, 0-100, * controlling the red, green and blue LEDs * * Red is the red LED at full, blue and green off * int red = { 100, 0, 0 } * Dim white is all three LEDs at 30% * int dimWhite = {30, 30, 30} * etc. * * Some common colors are provided below, or make your own * * LISTING THE ORDER: * In the main part of the program, you need to list the order * you want to colors to appear in, e.g. * crossFade(red); * crossFade(green); * crossFade(blue); * * Those colors will appear in that order, fading out of * one color and into the next * * In addition, there are 5 optional settings you can adjust: * 1. The initial color is set to black (so the first color fades in), but * you can set the initial color to be any other color * 2. The internal loop runs for 1020 interations; the 'wait' variable * sets the approximate duration of a single crossfade. In theory, * a 'wait' of 10 ms should make a crossFade of ~10 seconds. In * practice, the other functions the code is performing slow this * down to ~11 seconds on my board. YMMV. * 3. If 'repeat' is set to 0, the program will loop indefinitely. * if it is set to a number, it will loop that number of times, * then stop on the last color in the sequence. (Set 'return' to 1, * and make the last color black if you want it to fade out at the end.) * 4. There is an optional 'hold' variable, which pasues the * program for 'hold' milliseconds when a color is complete, * but before the next color starts. * 5. Set the DEBUG flag to 1 if you want debugging output to be * sent to the serial monitor. * * The internals of the program aren't complicated, but they * are a little fussy -- the inner workings are explained * below the main loop. * * April 2007, Clay Shirky */ // Output int redPin = 10; // Red LED, connected to digital pin 9 int grnPin = 11; // Green LED, connected to digital pin 10 int bluPin =12; // Blue LED, connected to digital pin 11 // Color arrays int black[3] = { 0, 0, 0 }; int white[3] = { 100, 100, 100 }; int red[3] = { 100, 0, 0 }; int green[3] = { 0, 100, 0 }; int blue[3] = { 0, 0, 100 }; int yellow[3] = { 90, 30, 0 }; int dimWhite[3] = { 30, 30, 30 }; int orange[3] = {90,90,20}; int cyan[3] = { 0, 90, 100}; int pink[3] = { 80, 0, 70}; int purple[3] = {40, 100, 2}; int wblue[3] = {15, 100, 30}; // etc. // Set initial color int redVal = black[0]; int grnVal = black[1]; int bluVal = black[2]; int wait = 1; // 10ms internal crossFade delay; increase for slower fades int hold = 1; // Optional hold when a color is complete, before the next crossFade int DEBUG = 1; // DEBUG counter; if set to 1, will write values back via serial int loopCount = 60; // How often should DEBUG report? int repeat = 0; // How many times should we loop before stopping? (0 for no stop) int j = 0; // Loop counter for repeat // Initialize color variables int prevR = redVal; int prevG = grnVal; int prevB = bluVal; // Set up the LED outputs void setup() { pinMode(redPin, OUTPUT); // sets the pins as output pinMode(grnPin, OUTPUT); pinMode(bluPin, OUTPUT); if (DEBUG) { // If we want to see values for debugging... Serial.begin(9600); // ...set up the serial ouput } } // Main program: list the order of crossfades void loop() { crossFade(red); crossFade(blue); crossFade(green); crossFade(yellow); crossFade(purple); crossFade(white); crossFade(cyan); crossFade(orange); crossFade(wblue); if (repeat) { // Do we loop a finite number of times? j += 1; if (j >= repeat) { // Are we there yet? exit(j); // If so, stop. } } } /* BELOW THIS LINE IS THE MATH -- YOU SHOULDN'T NEED TO CHANGE THIS FOR THE BASICS * * The program works like this: * Imagine a crossfade that moves the red LED from 0-10, * the green from 0-5, and the blue from 10 to 7, in * ten steps. * We'd want to count the 10 steps and increase or * decrease color values in evenly stepped increments. * Imagine a + indicates raising a value by 1, and a - * equals lowering it. Our 10 step fade would look like: * * 1 2 3 4 5 6 7 8 9 10 * R + + + + + + + + + + * G + + + + + * B - - - * * The red rises from 0 to 10 in ten steps, the green from * 0-5 in 5 steps, and the blue falls from 10 to 7 in three steps. * * In the real program, the color percentages are converted to * 0-255 values, and there are 1020 steps (255*4). * * To figure out how big a step there should be between one up- or * down-tick of one of the LED values, we call calculateStep(), * which calculates the absolute gap between the start and end values, * and then divides that gap by 1020 to determine the size of the step * between adjustments in the value. */ int calculateStep(int prevValue, int endValue) { int step = endValue - prevValue; // What's the overall gap? if (step) { // If its non-zero, step = 1020/step; // divide by 1020 } return step; } /* The next function is calculateVal. When the loop value, i, * reaches the step size appropriate for one of the * colors, it increases or decreases the value of that color by 1. * (R, G, and B are each calculated separately.) */ int calculateVal(int step, int val, int i) { if ((step) && i % step == 0) { // If step is non-zero and its time to change a value, if (step > 0) { // increment the value if step is positive... val += 1; } else if (step < 0) { // ...or decrement it if step is negative val -= 1; } } // Defensive driving: make sure val stays in the range 0-255 if (val > 255) { val = 255; } else if (val < 0) { val = 0; } return val; } /* crossFade() converts the percentage colors to a * 0-255 range, then loops 1020 times, checking to see if * the value needs to be updated each time, then writing * the color values to the correct pins. */ void crossFade(int color[3]) { // Convert to 0-255 int R = (color[0] * 255) / 100; int G = (color[1] * 255) / 100; int B = (color[2] * 255) / 100; int stepR = calculateStep(prevR, R); int stepG = calculateStep(prevG, G); int stepB = calculateStep(prevB, B); for (int i = 0; i <= 1020; i++) { redVal = calculateVal(stepR, redVal, i); grnVal = calculateVal(stepG, grnVal, i); bluVal = calculateVal(stepB, bluVal, i); analogWrite(redPin, redVal); // Write current values to LED pins analogWrite(grnPin, grnVal); analogWrite(bluPin, bluVal); delay(wait); // Pause for 'wait' milliseconds before resuming the loop if (DEBUG) { // If we want serial output, print it at the if (i == 0 or i % loopCount == 0) { // beginning, and every loopCount times Serial.print("Loop/RGB: #"); Serial.print(i); Serial.print(" | "); Serial.print(redVal); Serial.print(" / "); Serial.print(grnVal); Serial.print(" / "); Serial.println(bluVal); } DEBUG += 1; } } // Update current values for next loop prevR = redVal; prevG = grnVal; prevB = bluVal; delay(hold); // Pause for optional 'wait' milliseconds before resuming the loop }