dotmatrixdesign: Twitter LED Scroller Build Log

Here’s 4 seconds of it in action. It should be longer but...

Tue, 04 Dec 2007 03:14:08 -0500

Here’s 4 seconds of it in action. It should be longer but youtube doesn’t like it for some reason. You can see a few letters of a message.

Et, voila!

Tue, 04 Dec 2007 03:09:23 -0500

Then I get this idea that I'm going to cast the whole thing in clear polyster resin

Tue, 04 Dec 2007 03:08:43 -0500

Check out the fully detailed set of photos here

Then I write a bit of Arduino code:

Tue, 04 Dec 2007 03:06:01 -0500

//Very initial code borrowed from this example:
//**************************************************************//
// Name    : shiftOutCode, Hello World                         //
// Author  : Carlyn Maw,Tom Igoe                               //
// Date    : 25 Oct, 2006                                      //
// Version : 1.0                                               //
// Notes   : Code for using a 74HC595 Shift Register           //
//          : to count from 0 to 255                            //
//****************************************************************

//Pin connected to ST_CP of 74HC595
int latchPin = 9;
//Pin connected to SH_CP of 74HC595
int clockPin = 8;
////Pin connected to DS of 74HC595
int dataPin = 11;

int enablePin = 10; //Active Low!

//int col[5] = {6,5,2,3,4};
int col[5] = {4,3,2,5,6};

byte row;

byte pattern[80];

byte frame[5] = {B00010000,
                  B00010000,
                  B00010000,
                  B00010000,
                  B00010000,
                 };

int i;
int cycles = 0;
int framenum = 0;

int totalframes = 100;

int newline;
int reading_flag = 0;
int readindex = 0;
unsigned long read_timeout;
unsigned long req_timeout = 0;
int nextcheck = 1000;

//——States——
int state = 0;

void setup() {
//set pins to output because they are addressed in the main loop
pinMode(latchPin, OUTPUT);
pinMode(clockPin, OUTPUT);
pinMode(dataPin, OUTPUT);
pinMode(enablePin, OUTPUT);

for(i = 0; i    pinMode(col[i], OUTPUT);
}

    Serial.begin(9600);
}

void loop() {

      for (int j = 0; j
        //Set all the column registers high, except the columnwe want to show
        for(i = 0; i          digitalWrite(col[i], HIGH);
        }
        digitalWrite(col[j],LOW);

        //ground latchPin and hold low for as long as you are transmitting
        digitalWrite(latchPin, LOW);
        //disable the outputs while we are shifting
        digitalWrite(enablePin, HIGH);

        shiftOut(dataPin, clockPin, MSBFIRST, frame[j]);
        //return the latch pin high to signal chip that it
        //no longer needs to listen for information
        digitalWrite(latchPin, HIGH);
        //enable the outputs
        digitalWrite(enablePin, LOW);
        delay(1);
        //digitalWrite(col[j],HIGH);

      }//done displaying frame


      if (Serial.available() > 0) {
        newline = Serial.read();
        for (int j = 0; j            frame[j] = frame[j]         }

        frame[0] = frame[0] | (newline & 1) == 1;
        frame[1] = frame[1] | (newline & 2) == 2;
        frame[2] = frame[2] | (newline & 4) == 4;
        frame[3] = frame[3] | (newline & 8) == 8;
        frame[4] = frame[4] | (newline & 16) == 16;

      }

}

Then I write a little (okay, a LOT of) Processing code:

Tue, 04 Dec 2007 03:04:13 -0500

import processing.serial.*;

class twit {
String description;
int[] bytes = new int[len*5];
int pxlength;

twit () {
    description = “”;
    pxlength = 0;
}

void update () {
    nextpos = 0;
    for(int c = 0; c       description = description.toLowerCase();
      bytes = addLetter(description.charAt(c), bytes, nextpos+1);
    }
    pxlength = nextpos;
}

void drawpx (int xref, int yref) {
    for(int x = 0; x        if((bytes[x] & 1) == 1) {point(x+xref, yref+0);}
       if((bytes[x] & 2) == 2) {point(x+xref, yref+1);}
       if((bytes[x] & 4) == 4) {point(x+xref, yref+2);}
       if((bytes[x] & 8) == 8) {point(x+xref, yref+3);}
       if((bytes[x] & 16) == 16) {point(x+xref, yref+4);}
    }
}
}

int bits=5;
int len=200;

int i = 0, j = 0;
int sqrsize = 5;
int centerx, centery;
float avg;
float bias = .1;
int xpos, ypos;
float h = random(0,255);
int rowint[] = new int[len];
String lines[] = new String[20];
String new_lines[] = new String[20];
twit tweets[] = new twit[20];
int black = 0;
int nextpos = 0;

int next_tw_refresh = 30*60;
int current_twitter = 0;
int next_line = 0;
int rate = 15;

Serial myPort;

void setup()
{
background(255);
colorMode(RGB, 255);
ellipseMode(CORNERS);
strokeWeight(1);
noSmooth();
frameRate(30);

centerx = width/2;
centery = height/2;


println(Serial.list());
myPort = new Serial(this, Serial.list()[0], 9600);

for(i = 0; i     tweets[i] = new twit();
}

update_twits();

size(len*sqrsize, lines.length*sqrsize+1); // Size should be the first statement
}

void draw()
{

background(255);

stroke(255,0,0);
line(125,0,125,400);

stroke(0);
for(int count = 0; count     tweets[count].drawpx(0,count*(sqrsize+1));
}

   if(frameCount > next_tw_refresh) {
     println(“Refreshing messages…”);
     next_tw_refresh = frameCount + 3000; //30 fps x 60 seconds
     print(frameCount);
     update_twits();
   }

   if(frameCount > next_line_time) {
      myPort.write(tweets[current_twitter].bytes[nextline]);
      nextline++;
      if(nextline >= tweets[current_twitter].pxlength) {current_twitter++;}
       if(current_twitter >= 20) {current_twitter = 0;}
   }
}

void update_twits() {
new_lines = loadStrings(“http://linuxbox.dotmatrixdesign.net/~david/twit.php”);
if(new_lines[0] != lines[0]) {
    lines = new_lines;
    current_twitter = 0;
    for (int i=0; i       tweets[i].description = lines[i];
      tweets[i].update();
    }
    println(“new Twitters downloaded”);
}
}

void write_to_arduino (twit tosend) {
     myPort.write(‘w’);
     /*for(i = 0; i         myPort.write(byte(tosend.bytes[i]));
        print(tosend.bytes[i]);
        print(” “);
        delay(15);
     }*/
     myPort.write(byte(tosend.bytes));
     print(byte(tosend.bytes));
    println(“sent”);

}//end write

int[] addLetter(char letter, int bytes[], int startpos) {
int col[] = new int[8];
String colstr[] = new String[8];
int letter_length;
String zeros = “000”;

switch (letter) {
    case ‘a’:
      colstr[0] = “11110”;
      colstr[1] = “00101”;
      colstr[2] = “11110”;
      letter_length = 3;
      break;
    case ‘b’:
      colstr[0] = “11111”;
      colstr[1] = “10101”;
      colstr[2] = “01010”;
      letter_length = 3;
      break;
    case ‘c’:
      colstr[0] = “01110”;
      colstr[1] = “10001”;
      colstr[2] = “10001”;
      letter_length = 3;
      break;
    case ‘d’:
      colstr[0] = “11111”;
      colstr[1] = “10001”;
      colstr[2] = “01110”;
      letter_length = 3;
      break;
    case ‘e’:
      colstr[0] = “11111”;
      colstr[1] = “10101”;
      colstr[2] = “10101”;
      letter_length = 3;
      break;
    case ‘f’:
      colstr[0] = “11111”;
      colstr[1] = “00101”;
      colstr[2] = “00101”;
      letter_length = 3;
      break;
    case ‘g’:
      colstr[0] = “01110”;
      colstr[1] = “10001”;
      colstr[2] = “10101”;
      colstr[3] = “11101”;
      letter_length = 4;
      break;
    case ‘h’:
      colstr[0] = “11111”;
      colstr[1] = “00100”;
      colstr[2] = “11111”;
      letter_length = 3;
      break;
    case ‘i’:
      colstr[0] = “10001”;
      colstr[1] = “11111”;
      colstr[2] = “10001”;
      letter_length = 3;
      break;
    case ‘j’:
      colstr[0] = “11100”;
      colstr[1] = “10000”;
      colstr[2] = “11111”;
      letter_length = 3;
      break;
    case ‘k’:
      colstr[0] = “11111”;
      colstr[1] = “00100”;
      colstr[2] = “01010”;
      colstr[3] = “10001”;
      letter_length = 4;
      break;
    case ‘l’:
      colstr[0] = “11111”;
      colstr[1] = “10000”;
      colstr[2] = “10000”;
      letter_length = 3;
      break;
    case ‘m’:
      colstr[0] = “11110”;
      colstr[1] = “00001”;
      colstr[2] = “11110”;
      colstr[3] = “00001”;
      colstr[4] = “11110”;
      letter_length = 5;
      break;
    case ‘n’:
      colstr[0] = “11111”;
      colstr[1] = “00010”;
      colstr[2] = “00100”;
      colstr[3] = “11111”;
      letter_length = 4;
      break;
    case ‘o’:
      colstr[0] = “11111”;
      colstr[1] = “10001”;
      colstr[2] = “11111”;
      letter_length = 3;
      break;
    case ‘p’:
      colstr[0] = “11111”;
      colstr[1] = “00101”;
      colstr[2] = “00111”;
      letter_length = 3;
      break;
    case ‘q’:
      colstr[0] = “11111”;
      colstr[1] = “10001”;
      colstr[2] = “11111”;
      colstr[3] = “01000”;
      letter_length = 4;
      break;
    case ‘r’:
      colstr[0] = “11111”;
      colstr[1] = “00101”;
      colstr[2] = “11010”;
      letter_length = 3;
      break;
    case ‘s’:
      colstr[0] = “10111”;
      colstr[1] = “10101”;
      colstr[2] = “11101”;
      letter_length = 3;
      break;
    case ‘t’:
      colstr[0] = “00001”;
      colstr[1] = “11111”;
      colstr[2] = “00001”;
      letter_length = 3;
      break;
    case ‘u’:
      colstr[0] = “11111”;
      colstr[1] = “10000”;
      colstr[2] = “11111”;
      letter_length = 3;
      break;
    case ‘v’:
      colstr[0] = “00111”;
      colstr[1] = “11000”;
      colstr[2] = “00111”;
      letter_length = 3;
      break;
    case ‘w’:
      colstr[0] = “01111”;
      colstr[1] = “10000”;
      colstr[2] = “01111”;
      colstr[3] = “10000”;
      colstr[4] = “01111”;
      letter_length = 5;
      break;
    case ‘x’:
      colstr[0] = “11011”;
      colstr[1] = “00100”;
      colstr[2] = “11011”;
      letter_length = 3;
      break;
    case ‘y’:
      colstr[0] = “00111”;
      colstr[1] = “11100”;
      colstr[2] = “00111”;
      letter_length = 3;
      break;
    case ‘z’:
      colstr[0] = “11001”;
      colstr[1] = “10101”;
      colstr[2] = “10011”;
      colstr[3] = “10001”;
      letter_length = 4;
      break;

      case ‘0’:
      colstr[0] = “01110”;
      colstr[1] = “10001”;
      colstr[2] = “01110”;
      letter_length = 3;
      break;
     case ‘1’:
      colstr[0] = “00010”;
      colstr[1] = “11111”;
      letter_length = 2;
      break;
     case ‘2’:
      colstr[0] = “11010”;
      colstr[1] = “10101”;
      colstr[2] = “10010”;
      letter_length = 3;
      break;
     case ‘3’:
      colstr[0] = “10101”;
      colstr[1] = “10101”;
      colstr[2] = “11111”;
      letter_length = 3;
      break;
     case ‘4’:
      colstr[0] = “00111”;
      colstr[1] = “00100”;
      colstr[2] = “11111”;
      letter_length = 3;
      break;
     case ‘5’:
      colstr[0] = “10111”;
      colstr[1] = “10101”;
      colstr[2] = “01001”;
      letter_length = 3;
      break;
     case ‘6’:
      colstr[0] = “11111”;
      colstr[1] = “10101”;
      colstr[2] = “11101”;
      letter_length = 3;
      break;
     case ‘7’:
      colstr[0] = “11001”;
      colstr[1] = “00101”;
      colstr[2] = “00011”;
      letter_length = 3;
      break;
     case ‘8’:
      colstr[0] = “11111”;
      colstr[1] = “10101”;
      colstr[2] = “11111”;
      letter_length = 3;
      break;
     case ‘9’:
      colstr[0] = “00111”;
      colstr[1] = “00101”;
      colstr[2] = “11111”;
      letter_length = 3;
      break;

    case ’ ‘:
      colstr[0] = “00000”;
      colstr[1] = “00000”;
      letter_length = 2;
      break;
    case ‘!’:
      colstr[0] = “10111”;
      letter_length = 1;
      break;
    case ‘.’:
    case ‘,’:
      colstr[0] = “10000”;
      letter_length = 1;
      break;
    case ‘:’:
      colstr[0] = “01010”;
      letter_length = 1;
      break;
    case ‘/’:
      colstr[0] = “11000”;
      colstr[1] = “00100”;
      colstr[2] = “00011”;
      letter_length = 3;
      break;
    case ‘\’:
      colstr[0] = “00011”;
      colstr[1] = “00100”;
      colstr[2] = “11000”;
      letter_length = 3;
      break;
    case ‘+’:
      colstr[0] = “00100”;
      colstr[1] = “01110”;
      colstr[2] = “00100”;
      letter_length = 3;
      break;
    case ‘-‘:
      colstr[0] = “00100”;
      colstr[1] = “00100”;
      colstr[2] = “00100”;
      letter_length = 3;
      break;
    case ‘@’:
      colstr[0] = “11111”;
      colstr[1] = “10001”;
      colstr[2] = “11101”;
      colstr[3] = “11101”;
      letter_length = 4;
      break;
    case ‘?’:
      colstr[0] = “00001”;
      colstr[1] = “10101”;
      colstr[2] = “00111”;
      letter_length = 3;
      break;
    case ‘'’:
      colstr[0] = “00011”;
      letter_length = 1;
      break;
   case ‘*’:
      colstr[0] = “00010”;
      colstr[1] = “00111”;
      colstr[2] = “00010”;
      letter_length = 3;
      break;
   case ‘(‘:
      colstr[0] = “01110”;
      colstr[1] = “10001”;
      letter_length = 2;
      break;
   case ‘)’:
      colstr[0] = “10001”;
      colstr[1] = “01110”;
      letter_length = 2;
      break;

    default:
      colstr[0] = “11111”;
      colstr[1] = “11111”;
      colstr[2] = “11111”;
      letter_length = 3;
      break;
}

for(int ch = 0; ch     colstr[ch] = zeros.concat(colstr[ch]);
    bytes[startpos+ch] = unbinary(colstr[ch]);
}

nextpos = startpos + letter_length;

return(bytes);
}

Thanks to the Twitter API

Tue, 04 Dec 2007 03:03:16 -0500

Thanks to the Twitter API

So I write a little PHP code

Tue, 04 Dec 2007 03:02:24 -0500

$ch = curl_init();

// set URL and other appropriate options
$test_str = “http://twitter.com/statuses/friends_timeline/davidnin.xml”;
curl_setopt($ch, CURLOPT_URL, $test_str);
curl_setopt($ch, CURLOPT_HTTPAUTH, CURLAUTH_BASIC);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HEADER, false);

// grab URL and pass it a string
$str = curl_exec($ch);

// close cURL resource, and free up system resources
curl_close($ch);

if (!$myxml=simplexml_load_string($str)) {
echo ‘Error reading the XML file’;
}

foreach($myxml as $status){

echo $status->{‘user’}->{‘screen_name’} . “: ” . $status->{‘text’} . “\n”;

} //end for each status

?>

More time passes, and I read this incredibly inspiring book

Tue, 04 Dec 2007 02:59:52 -0500

More time passes, and I read this incredibly inspiring book

And it actually works!

Tue, 04 Dec 2007 02:57:02 -0500

…with a couple of slight tweaks of course. (note the tiny green and yellow wires)

3 weeks pass. then magically, from the far east...

Tue, 04 Dec 2007 02:56:03 -0500

Another shot from their confirmation

Tue, 04 Dec 2007 02:53:39 -0500

Another shot from their confirmation

You send them your board designs, they send you back a cool...

Tue, 04 Dec 2007 02:53:16 -0500

You send them your board designs, they send you back a cool acknowledgement generated by their DRC bot.

I had this PCB built by a great SparkFun.com service: batchpcb.com

Tue, 04 Dec 2007 02:52:00 -0500

I had this PCB built by a great SparkFun.com service: batchpcb.com

Here's a link to a zip file with my Eagle schematics and board design

Tue, 04 Dec 2007 02:49:01 -0500

Here's a link to a zip file with my Eagle schematics and board design

Behold! After some newly learned tricks, and some fun...

Tue, 04 Dec 2007 02:46:04 -0500

Behold! After some newly learned tricks, and some fun auto-routing by Eagle, we have a board design. I modified this one with the expectation of using chemicals to etch my own. However…

And now the board needs to be laid out.

Tue, 04 Dec 2007 02:45:02 -0500

And now the board needs to be laid out.

A schematic comes together…

Tue, 04 Dec 2007 02:44:34 -0500

A schematic comes together…

EagleCAD, love it.

Tue, 04 Dec 2007 02:43:40 -0500

EagleCAD, love it.:

I learned everything I needed to know about EagleCad from this website.

Some drawings for future reference

Tue, 04 Dec 2007 02:33:02 -0500

Saying hello for the first time

Tue, 04 Dec 2007 02:21:30 -0500