LED Diffuser

After learning Pulse Width Modulation and serial communication with the laptop at the lab, this assignment of building the LED diffuser was to explore these features in more depth. I started with setting three resistors, LED lights, and connecting wires. I carefully built LED circuit by using pin 9, 10, and 11, which can support Pulse Width Modulation. Then, by using the Arduino Sketchbook, I coded a program so that I can control RGB values of LED lights by pressing letters ‘r’, ‘g’, and ‘b’ multiple times. The program is designed to perform as follows:
-       Each time a letter (either ‘r’,’g’, or ‘b’) is pressed, the value of that particular color LED light increases 25.5, which is about 10% of maximum value.
-       When a LED light reaches maximum value, it goes back to 0 and start to count from the beginning.
-       When a user type ‘off’ via serial, all the LED lights will turn off.
Then, I built a diffuser by using a ping pong ball. I used a electric drill to make a hole on one side of the ball. I covered LED lights by the ping pong ball and the diffuser reflected mixed color of three LED lights.  

Components used:
1- Arduino Uno
1- Breadboard
1- 220ohms resistors
1- LED lights (red, green, blue)
7- Connecting wires
1- Ping pong ball (diffuser)
 

Code:
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   = 10;   // Red LED,   connected to digital pin 9
int greenPin = 11;  // Green LED, connected to digital pin 10
int bluePin  = 9;  // Blue LED,  connected to digital pin 11
 
int redColorVal= 0; // setting intial color values
int greenColorVal = 0;
int blueColorVal = 0;
 
void setup() {
  pinMode(redPin,   OUTPUT);   // sets the pins as output
  pinMode(greenPin, OUTPUT);  
  pinMode(bluePin,  OUTPUT);
  Serial.begin(9600);
  analogWrite(redPin,   0);   // set them all to mid brightness
  analogWrite(greenPin, 0);   // set them all to mid brightness
  analogWrite(bluePin,  0);   // set them all to mid brightness
  Serial.println("enter 'off' to turn off");
  Serial.println("enter color combination in rgb (e.g. 'rrrggggb') "); 
}
 
void loop () {
  // clear the string
  memset(serInString, 0, 100);
  //read the serial port and create a string out of what you read
  readSerialString(serInString);
 
 
//  colorCode = serInString[0];
  if(strcmp(serInString, "off") == 0){
    analogWrite(redPin, 0);
    analogWrite(greenPin, 0);
    analogWrite(bluePin, 0);
    memset(serInString, 0, 100);
}
 
  for(int i = 0; i <= sizeof(serInString); i++){
   colorCode = serInString[i];
  if (colorCode == 'r'){
   if (redColorVal+25.5 >= 256){
    redColorVal = redColorVal+25.5;
    redColorVal = redColorVal%256;
    Serial.print("Red is");
    Serial.println(redColorVal);
   }
   else{
     redColorVal = redColorVal +25.5;
   }
   analogWrite(redPin, redColorVal);
   Serial.print("Setting Red to ");
   Serial.print(redColorVal);
   Serial.println();
  
  }
 
  if (colorCode == 'g'){
   if (greenColorVal+25.5 >= 256){
    greenColorVal = greenColorVal+25.5;
    greenColorVal = greenColorVal%256;
    Serial.print("Green is ");
    Serial.println(greenColorVal);
   
   }
   else{
     greenColorVal = greenColorVal +25.5;
   }
   analogWrite(greenPin, greenColorVal);
   Serial.print("Setting Green to ");
   Serial.print(greenColorVal);
   Serial.println();
  }
  
   if (colorCode == 'b'){
   if (blueColorVal+25.5 >= 256){
    blueColorVal = blueColorVal+25.5;
     blueColorVal = blueColorVal%256;
    Serial.print("Blue is ");
    Serial.println(blueColorVal);
   
   }
   else{
     blueColorVal = blueColorVal +25.5;
   }
   analogWrite(bluePin, blueColorVal);
  
  
   Serial.print("Setting Blue to ");
   Serial.print(blueColorVal);
   Serial.println();
  }
  
  }
  
   
 
  delay(500);  // wait a bit, for serial data
}
 
//read a string from the serial and store it in an array
//you must supply the array variable
void readSerialString (char *strArray) {
  int i = 0;
  if(!Serial.available()) {
    return;
  }
  while (Serial.available()) {
    strArray[i] = Serial.read();
    i++;
  }
}