# Theory and Practice of Tangible User Interfaces

### Announcements

November 24, 2007
Reading for November 27th, are now posted. Enjoy!

October 2, 2007
To upload your thoughtless acts, create a new assignment page like any other lab. You'll see "Thoughtless Acts" listed as one of the assignment options.

May 24, 2008
This site has been archived and is no longer editable. Stay tuned for the next version, coming in the fall!

# Revision of Lab2 from Wed, 09/12/2007 - 19:30

Project Members:
Kenghao Chang

#### Result in the in-lab exercises

The photo is attached.

#### HOMEWORK 2)

I used the caps of my sun cream to be the diffuser.

#### HOMEWORK 3)

In this part, i use three variables redCount, greenCount, and blueCount to count how many repetitions of each r, g, b are. Then, i set the brightness based on the calcucated percentage.

##### Code

/*
* Serial RGB LED
* ---------------
* Serial commands control the brightness of R,G,B LEDs

* Command structure is "<colorCode>*", where "colorCode" is
* one of "r","g", or "b".
* For example, pressing ‘r’ 5 times will set the brightness to 50% (or brightness = 127)
* and pressing ‘r’ 10 times will set it to 100% (or brightness = 255).
*
*
*
*/

//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') :");
}

void loop () {
//read the serial port and create a string out of what you read

//UNCOMMENT ONE OF THE FOLLOWING COMMANDS, OR NOTHING WILL HAPPEN WHEN YOU
//RUN THE PROGRAM...

myProcessRepeatKeyCommands(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) {
i++;
}
}

void myProcessRepeatKeyCommands(char *strArray, int maxLength) {
int i = 0;

int redCount = 0, greenCount = 0, blueCount = 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') {
redCount ++;

//If the character is g (green)...
} else if (colorCode == 'g') {
greenCount ++;

//If the character is b (blue)...
} else if (colorCode == 'b') {
blueCount ++;
}

//Move on to the next character in the string
//From here, the code continues executing from the "while" line above...
i++;
}

if (i > 0) {

redValue = 255 * redCount / 10;
analogWrite(redPin, redValue);
Serial.print("setting color r to ");
Serial.println(redValue);
greenValue = 255 * greenCount / 10;
analogWrite(greenPin, greenValue);
Serial.print("setting color g to ");
Serial.println(greenValue);
blueValue = 255 * blueCount / 10;
analogWrite(bluePin, blueValue);
Serial.print("setting color b to ");
Serial.println(blueValue);

}

}

#### HOMEWORK 4)

##### Code

/*
* Serial RGB LED
* ---------------
* Serial commands control the brightness of R,G,B LEDs

* Command structure is "<colorCode>*", where "colorCode" is
* one of "r","g", or "b".
* For example, pressing ‘r’ 5 times will set the brightness to 50% (or brightness = 127)
* and pressing ‘r’ 10 times will set it to 100% (or brightness = 255).
*
*
*
*/

//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;
int redCount = 5, greenCount = 5, blueCount = 5;

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 () {
switch(c) {
case 'r':
redCount ++;
break;
case 'g':
greenCount ++;
break;
case 'b':
blueCount ++;
break;
default:
return;
}

redValue = 255 * (redCount % 10)/ 10;
greenValue = 255 * (greenCount % 10)/ 10;
blueValue = 255 * (blueCount % 10)/ 10;
analogWrite(redPin, redValue);
analogWrite(greenPin, greenValue);
analogWrite(bluePin, blueValue);

Serial.print("setting color (red, green, blue) to (");
Serial.print(redValue);
Serial.print(", ");
Serial.print(greenValue);
Serial.print(", ");
Serial.print(blueValue);
Serial.println(")");
}