Assignment: Digital I/O with Arduino Boards + Diffuser

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Assignment: Digital I/O with Arduino Boards + Diffuser
Collaborators:

Description

The goal of this exercise was to design a diffuser for the red, green and blue LEDs. The RGB values of the LEDs were to be varied with key presses. In this particular code (see code for dedications), the intensity of the LEDs can be changed by altering the number of key presses of the letter that corresponds to that LED. For instance, a sequence of rrb increases the intensity of the red LED by 20 and the blue by 10 respectively. I have also modified this code to allow for decreasing the intensities as well. In this case, a seqence of -(rr)b, decreases the intensity of r by 20 and increases blue by 10.

For the diffuser, I tried many things. I have shown a few here. These are a shot glass wrapped in gauze, a plastic lid wrapped in a foam ribbon, and a wine glass covered by a glossy party tissue.

Components Used

Arduino Board

3 220 Ohm resistors

1 red, blue and green LEDs

Wires

Breadboard

shot glass

gauze

plastic lid

foam ribbon

wine glass

fancy party tissue

Code

/*
* Serial RGB LED
* ---------------
* Serial commands control the brightness of R,G,B LEDs
*
* Command 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>
*
*/
*/This code was also popular among the students in the Fall '08 class. My addition to it is playing with decreasing the RBG intensities.

//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 = 127;
int greenValue = 127;
int blueValue = 127;

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 or -(rr)gb to reduce red and increase green and  blue') :"); 
}

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);

//Or write your own function...
//YOUR_FUNCTION_HERE(serInString);

//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 there is a negative sign before the letter then reduce brightness
if (colorCode == '-'){
int j = i+1;
if (serInString[j] == '('){
while (serInString[j] != ')') {
char tempColorCode = serInString[j+1];  
if (tempColorCode == 'r') {
//Increase the current red value by 10, and if you reach 255 go back to 0
redValue = (redValue - 10) % 255;
analogWrite(redPin, redValue);
Serial.print("reducing color r to ");
Serial.println(redValue);

//If the character is g (green)...
} else if (tempColorCode == 'g') {
greenValue = (greenValue - 10) % 255;
analogWrite(greenPin, greenValue);
Serial.print("reducing color g to ");
Serial.println(greenValue);

//If the character is b (blue)...
} else if (tempColorCode == 'b') {
blueValue = (blueValue - 10) % 255;
analogWrite(bluePin, blueValue);
Serial.print("reducing color b to ");
Serial.println(blueValue);    
}   
j++;
i = j;
}
}
}
//If the character is r (red)...
else if (colorCode == 'r') {
//Increase the current red value by 10, and if you reach 255 go back to 0
redValue = (redValue + 10) % 255;
analogWrite(redPin, redValue);
Serial.print("increasing color r to ");
Serial.println(redValue);

//If the character is g (green)...
} else if (colorCode == 'g') {
greenValue = (greenValue + 10) % 255;
analogWrite(greenPin, greenValue);
Serial.print("increasing color g to ");
Serial.println(greenValue);

//If the character is b (blue)...
} else if (colorCode == 'b') {
blueValue = (blueValue + 10) % 255;
analogWrite(bluePin, blueValue);
Serial.print("increasing color b to ");
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;
}
}