Arduino Workshop

The first Arduino workshop. I have already use Arduino before and have the basic understanding of it. I am also quite familiar with electronics and prototyping. So the section played out to be fairly easy for me.

We basically looked at the Arduino Uno and the coding platform, and some simple setting with the Arduino pins, such as #define directive, void setup and void loop, which is all good fun.

Although I can understand everything in the section, I can tell why the code is set to be in some certain way, I am still quite far from writing my own code without looking at some references. which is why I need to learn more about it and practice more of it too. 

Later on that section, Tom gave an example of cooperating Arduino with Processing, using 2 anolog reads and a digital read, with serial port to draw on Processing. 

The following codes are from Tom.

Arduino:

#define X_POT A0

#define Y_POT A1

#define CLR_BTN 7



void setup() {

pinMode( X_POT, INPUT );

pinMode( Y_POT, INPUT );

pinMode( CLR_BTN, INPUT );

Serial.begin( 9600 );

}



void loop() {

Serial.print( analogRead( X_POT ) );

Serial.print( "," );

Serial.print( analogRead( Y_POT ) );

Serial.print( "," );

Serial.print( digitalRead( CLR_BTN ) );

Serial.println();

}




In the Serial.Print(",") means show a comma in between each variable on 

Serial Monitor 

Serial.println() means to create a new line after the each run.



Processing:


import processing.serial.*;



Serial arduino;

int x = 0;

int y = 0;

int prev_x = 0;

int prev_y = 0;

void setup() {

// Create a VGA canvas

size( 800, 600 );



// Get a list of serial ports

String ports[] = Serial.list();

int id = 0;

// Find an Arduino tty.usb* port

for ( int i = 0; i < ports.length; i++ ) {

if ( ports[i].indexOf( "tty.usb" ) != -1 )

id = i;

}



// Connect to the Arduino

println( "Connecting to: " + ports[id] );

arduino = new Serial( this, ports[id], 9600 );

// Start looking for data  

arduino.bufferUntil( '\n' );

// Set background colour

background( 204 );

// Set line thickness

strokeWeight( 2 );

}

void draw() {

// Turn on stroke

stroke( 0 );

// Draw a line from current to previous X,Y

line( x, y, prev_x, prev_y );

// Store X,Y position for next frame

prev_x = x;

prev_y = y;

// Set the fill colour to transparent white

fill( 255, 255, 255, 2 );

// Turn off stroke

noStroke();



// Fill screen with transparent white

rect( 0, 0, width, height );  

}



// New Serial Data Event

void serialEvent(Serial p) {

// Trim white space and split data on commas

String[] data = split( trim( p.readString() ), ',' );

// If there are 3 bits of data process it.

if ( data.length == 3 ) {

// Update X/Y positions for drawing

x = int( map ( int( data[0] ), 0, 1024, 0, width ) );

y = int( map ( int( data[1] ), 0, 1024, 0, height ) );

// If 3rd data item is 1 clear the screen

if ( int( data[2] ) == 1 ) {

background( 204 );

}

}

}

// Key Press Event

void keyPressed() {

// If key is s then save image of canvas

if ( key == 's' ) {

saveFrame();

println( "Saved" );

}

}





I know the program Processing, but only had a chance to use it for once or twice, 

therefore I am not exactly clear why is it coded in

this way but I guess this is something I will and keen to learn in the

future.