Description
This is where you will put a description of your assignment. Write a couple paragraphs describing your approach. What does it do? Why did you choose this approach over others? What problems did you run into?
I build 3 LED diffuser with my Arduino board. Using PWM, I could control the brightness of each of the LEDs, and also the serial I/O made (almost) real-time color control. I basically followed the steps that Prof. Ryokai suggested. I put three LED together on the breadboard. I tried to be careful about the polarity of the LED and the wirings on Arduino board for PWM capability. Then, I made them blink in certain time frame with my code from the first assignment. To mix the light colors, I chose cotton and folded tracing paper. I initially tried with the paper only, but the LEDs were too bright to be perceived as a mixed color. I also had fun with a different diffuser found at home. My son's favorite toy cup made a great diffuser with a cotton ball. Afterward, I started working with serial I/O with changing brightness. Arduino code was little different from the only language that I know, which is python, but I could figure it out easily with help of Nahman. The serial input made the LED brightness 10% brighter. I added three other keys, T, H, N, which are right next to R, G, B to decrease brightness.
Components Used
1- Arduino Uno
3- LEDs in Red, Green, Blue
3- Resistor
1- Breadboard
Code
/*
* Serial RGB LED
* ---------------
* Serial commands control the brightness of R,G,B LEDs
*
* Command
* E.g. "r" increase the red LED color value 10%.
* "t" decrease the red LED color value 10%
*
* adapted 10 Feb 2013
* KellyP
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;
char colorCode2;
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
float colorValR = 0;
float colorValG = 0;
float colorValB = 0;
int colorMax = 255;
void setup() {
pinMode(redPin, OUTPUT); // sets the pins as output
pinMode(greenPin, OUTPUT);
pinMode(bluePin, OUTPUT);
Serial.begin(9600);
analogWrite(redPin, colorValR); // set them all to mid brightness
analogWrite(greenPin, colorValG); // set them all to mid brightness
analogWrite(bluePin, colorValB); // set them all to mid brightness
Serial.println("enter color command (e.g. 'r' to increase 10%) :");
}
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( colorCode == 'r' || colorCode == 'g' || colorCode == 'b' ) {
Serial.print("Increasing color ");
Serial.print(colorCode);
Serial.print(" to ");
if(colorCode == 'r'){
if (colorValR<255){
colorValR = colorValR+(colorMax*0.1);
}
Serial.print(colorValR);
analogWrite(redPin, colorValR);
}
else if(colorCode == 'g'){
if (colorValG<255){
colorValG = colorValG+(colorMax*0.1);
}
Serial.print(colorValG);
analogWrite(greenPin, colorValG);
}
else if(colorCode == 'b'){
if (colorValB<255){
colorValB = colorValB+(colorMax*0.1);
}
Serial.print(colorValB);
analogWrite(bluePin, colorValB);
}
Serial.println();
serInString[0] = 0; // indicates we've used this string
}
else if( colorCode == 't' || colorCode == 'h' || colorCode == 'n' ) {
if( colorCode == 't'){
colorCode2 = 'r';
}
else if ( colorCode == 'h'){
colorCode2 = 'g';
}
else if ( colorCode == 'n' ){
colorCode2 = 'b';
}
Serial.print("Decreasing color ");
Serial.print(colorCode2);
Serial.print(" to ");
if(colorCode == 't'){
if (colorValR>0){
colorValR = colorValR-(colorMax*0.1);
}
Serial.print(colorValR);
analogWrite(redPin, colorValR);
}
else if(colorCode == 'h'){
if (colorValG>0){
colorValG = colorValG-(colorMax*0.1);
}
Serial.print(colorValG);
analogWrite(greenPin, colorValG);
}
else if(colorCode == 'n'){
if (colorValB>0){
colorValB = colorValB-(colorMax*0.1);
}
Serial.print(colorValB);
analogWrite(bluePin, colorValB);
}
Serial.println();
serInString[0] = 0; // indicates we've used this string
}
delay(100); // 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++;
}
}
Images
Attached below :)
