Control the RGB value
Use the Arduino to control the RGB value of the lights with multiple keypresses. When you press r, g, b N times, it increases the brightness by 10%*N, and when you reach its maximum brightness (100%), it goes back to 0% brightness.
Components Used
Light Emitting Diode (LED) * 3
Resistor * 3
6 yellow wires, 1 black wire
Arduino Code
/*
* Serial RGB LED
* ---------------
* Serial commands control the brightness of R,G,B LEDs
*
* rrrrrCommand structure is "<colorCode><colorVal>", where "colorCode" is
* one of "r","g",or "b" and "colorVal" is a number 0 to 255.
* E.g. "r0" turns the red LED off.
* "g127" turns the green LED to half brightness
* "b64" turns the blue LED to 1/4 brightness
*
* Alternate command structure is "<colorCode>*", where "colorCode" is
* one of "r","g", or "b".
* E.g. "r" increases the red LED brightness by 10
* "rrr" increases the red LED brightness by 30
* "ggb" increases the green LED brightness by 20 and the blue by 10
*
* Created 18 October 2006
* copyleft 2006 Tod E. Kurt <tod@todbot.com>
* http://todbot.com/
*
* Adapted 5 September 2007
* copylefter 2007 Ryan Aipperspach <ryanaip@alumni.rice.edu>
*
* Modified 12 September 2007
* iSchool Tangible User Interfaces Lab2 Homework
*
*/
//include support for manipulating strings.
//for a useful string comparison function, see the bottom of this file... stringsEqual()
#include <stdio.h>
#include <string.h>
char serInString[100]; // array that will hold the different bytes of the string. 100=100characters;
// -> you must state how long the array will be else it won't work properly
char colorCode;
int colorVal;
int redPin = 9; // Red LED, connected to digital pin 9
int greenPin = 10; // Green LED, connected to digital pin 10
int bluePin = 11; // Blue LED, connected to digital pin 11
int redValue = 50; // default value: 50%
int greenValue = 50; // default value: 50%
int blueValue = 50; // default value: 50%
int red; // value varies from 0 to 255
int green; // value varies from 0 to 255
int blue; // value varies from 0 to 255
void setup() {
pinMode(redPin, OUTPUT); // sets the pins as output
pinMode(greenPin, OUTPUT);
pinMode(bluePin, OUTPUT);
Serial.begin(9600);
analogWrite(redPin, redValue); // set them all to mid brightness
analogWrite(greenPin, greenValue); // set them all to mid brightness
analogWrite(bluePin, blueValue); // set them all to mid brightness
Serial.println("enter color command (e.g. 'r43 or rrrrrrrrbbbb') :");
}
void loop () {
//read the serial port and create a string out of what you read
readSerialString(serInString, 100);
//UNCOMMENT ONE OF THE FOLLOWING COMMANDS, OR NOTHING WILL HAPPEN WHEN YOU
//RUN THE PROGRAM...
//Uncomment the following line to read commands of the form 'r245' or 'b3'
//processNumericalCommands(serInString);
//Uncomment the following line to read commands of the form 'rrrb'
processRepeatKeyCommands(serInString, 100);
//Erase anything left in the serial string, preparing it for the
//next loop
resetSerialString(serInString, 100);
delay(100); // wait a bit, for serial data
}
void resetSerialString (char *strArray, int length) {
for (int i = 0; i < length; i++) {
strArray[i] = '\0';
}
}
//read a string from the serial and store it in an array
//you must supply the array variable
void readSerialString (char *strArray, int maxLength) {
int i = 0;
if(!Serial.available()) {
return;
}
while (Serial.available() && i < maxLength) {
strArray[i] = Serial.read();
i++;
}
}
//go through the string, and increase the red value for each 'r',
//the green value for each 'g', and the blue value for each 'b'.
//For example "rrrg" increases red by 30 and green by 10.
void processRepeatKeyCommands(char *strArray, int maxLength) {
int i = 0;
//loop through the string (strArray)
//i = the current position in the string
//Stop when either (a) i reaches the end of the string or
// (b) there is an empty character '\0' in the string
while (i < maxLength && strArray[i] != '\0') {
//Read in the character at position i in the string
colorCode = serInString[i];
//If the character is r (red)...
if (colorCode == 'r') {
//Increase the current red value by 10%, which is 25.5 in RGB value, and if you reach 255 go back to 0
redValue = (redValue + 10) % 100;
red = (redValue * 255) / 100;
analogWrite(redPin, red);
Serial.print("setting color red to brightness % ");
Serial.println(redValue);
//If the character is g (green)...
} else if (colorCode == 'g') {
greenValue = (greenValue + 10) % 100;
green = (greenValue * 255) / 100;
analogWrite(greenPin, green);
Serial.print("setting color green to brightness % ");
Serial.println(greenValue);
//If the character is b (blue)...
} else if (colorCode == 'b') {
blueValue = (blueValue + 10) % 100;
blue = (blueValue * 255) / 100;
analogWrite(bluePin, blue);
Serial.print("setting color blue to brightness % ");
Serial.println(blueValue);
}
//Move on to the next character in the string
//From here, the code continues executing from the "while" line above...
i++;
}
}
//change the value of the red, green, or blue LED according to the command received.
//for example, r240 sets the red LED to the value 240 (out of 255)
void processNumericalCommands(char *strArray) {
//read in the first character in the string
colorCode = serInString[0];
//if the first character is r (red), g (green) or b (blue), do the following...
if( colorCode == 'r' || colorCode == 'g' || colorCode == 'b' ) {
//convert the string to an integer
//(start at the second character, or the beginning of the string '+1')
colorVal = atoi(serInString+1);
Serial.print("setting color ");
Serial.print(colorCode);
Serial.print(" to ");
Serial.print(colorVal);
Serial.println();
if(colorCode == 'r')
analogWrite(redPin, colorVal);
else if(colorCode == 'g')
analogWrite(greenPin, colorVal);
else if(colorCode == 'b')
analogWrite(bluePin, colorVal);
}
}
//compare two strings to see if they are equal
//compares the first 'numCharacters' characters of string1 and string2 to
//see if they are the same
//
//E.g. stringsEqual("hello","hello",5) => true
// stringsEqual("hello","helaabbnn",3) => true
// stringsEqual("hello","helaa",5) => false
boolean stringsEqual(char *string1, char *string2, int numCharacters) {
if (strncmp(string1, string2, numCharacters) == 0) {
return true;
} else {
return false;
}
}
Images
I used my translucent white board made of glass as a diffuser.
Comments
GSI Comments
Nice work. I like the scale of your diffuser -- it has the beginnings of something "architectural"... I wonder if it would be possible to get the LEDs to illuminate more of the glass, even when the lights are on in the room, perhaps by building a reflector box behind the glass?
Your code is fine, but trying to make a few more modifications to the code is definitely a great way to learn more about Arduino programming. Being creative with code and with physical components (like the diffuser) can create really interesting results.