Erik's Blog: Discussing IT, personal fabrication and a new and better world

Entries from September 2008

Wednesday, September 24. 2008

[RepRap] My interactive RepRap ... Posted by Erik de Bruijn in RepRap at 11:04

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[RepRap] My interactive RepRap control and G-Code parsing program

This is version 0.1 of my reprap controller. I don't have much time to work on in so I'll publish it in a non-finished state (then again, what is 'finished'?). It still needs an open minicom session with the appropriate settings. I can make stty do this, but it works for me right now...

[edit] This work is now documented Here, at the RepRap Builders Wiki[/edit]



#!/usr/bin/php -q
<?php
/* ------------------------------------------------------------
// dotG 2 GCode
// By Erik de Bruijn, september 2008
//
// this script parses cam.py's .g files and pre-processes them 
// for .gcode files that run on RepRap Generation 2 electro-
// nics with the GCode firmware.
//
// Depends on php5-cli (ubuntu/debian: apt-get install php5-cli)
// Licence: GPLv3
//          See http://www.gnu.org/licenses/gpl.txt
// When distributing it, please include a copy of the licence.
   ----------------------------------------------------------*/
// todo: add ; in front of lines than can be skipped.

if(!isset($argv[2])) die("dotG2Gcode v0.1 - by Erik de Bruijn

Usage:
1. Make a .g file with MIT's cam.py

Process a file:
$argv[0] convert inputfile.g outputfile.gcode

Control the machine interactively line-by-line:
$argv[0] i[nteractive] [inputfile.g]

");

$fdata = file($argv[2]);
foreach($fdata as $line)
{
  if(trim($line)=='%') continue; // start & end notice... don't send
  if(!strlen(trim($line))) continue; // remove blank lines
  if(trim($line)=='O1234') continue;
  if($line{0}=='%') continue;

  if(ereg("G([0-9]+)[^0-9]",$line,$gcode))
  {
//echo "G code: ".$gcode[1];
    switch($gcode[1])
    {
//       case 90: continue; break;
    }
  }
  if($line{0}=='G') $out[]=trim($line)."\n";
  if($line{0}=='M') $out[]=trim($line)."\n";
  if($line{0}=='X') $out[]="G1".trim($line)."\n";
}

if(($argv[1]=='convert') || ($argv[1]{0}=='c'))
{
  $fileout = implode('',$out);
  file_put_contents($argv[3],$fileout);
}

$commands = array(
'Quit'=>array('do'=>'quit','desc'=>'Exit the program.','aliasses'=>'Exit'),
'Help'=>array('do'=>'help','desc'=>'Show this help.'),
'Speed'=>array('do'=>'speed','desc'=>'Change G1 movement speeds'),
'History'=>array('do'=>'history','desc'=>'Show the history of commands'),
'Home'=>array('do'=>'home','desc'=>'Go to home position (G1X0Y0Z0)'),
'helpg'=>array('do'=>'helpg','desc'=>'Explanation of G codes'),
'absolute'=>array('do'=>'absolute','desc'=>'Absolute positioning (G90)'),
'relative'=>array('do'=>'relative','desc'=>'Relative positioning (G91)'),
'newhome'=>array('do'=>'newhome','desc'=>'Make this the new home (G92)'),
'fan_on'=>array('do'=>'fan_on','desc'=>'Turn on the cooler fan (M106)'),
'fan_off'=>array('do'=>'fan_off','desc'=>'Turn on the cooler fan (M107)'),
'spindle_on'=>array('do'=>'fan_on','desc'=>'Turn on the spindle (M106)'),
'spindle_off'=>array('do'=>'fan_off','desc'=>'Turn on the spindle (M107)'),
'unit_mm'=>array('do'=>'unit_mm','desc'=>'Make the milimeter the basic unit (G21)'),
'unit_inch'=>array('do'=>'unit_mm','desc'=>'Make the milimeter the basic unit (G20)'),
);

foreach($commands as $myac=>$bla)
{
  $myAutoComplete[]='/'.strtolower($myac);
}
// $myAutoComplete[]='';
readline_completion_function('autoComplete');

if(($argv[1]=='interactive') || ($argv[1]{0}=='i'))
{
echo "                __
  _| | __ | | / __|
 / ` |/  | _| |  
| (| | () | || || |
 _,|__/ _|__|\n";
echo "----INTERACTIVE MODE----\nCommands start with '/'. /h is help! Tab to autocomplete\n";
$dev = "/dev/ttyUSB0";

$reprap= new RepRap($dev);
$reprap->gcode("G21\n"); 
$unit = 'mm';
$linenr = 0;
$fp = fopen($dev,'r');
// stty ispeed 19200 ospeed 19200 cs8 raw -echo -parenb -cstopb onlcr < $port
// if(!is_writable($dev)) echo "Warning: Device $dev is not writable.\n";
$G='';
  while(!$abort)
  {
    $prompt = ".G$G: ";
    $cmd = readline($prompt);
    if(($cmd!='n')&&($cmd!='r')&&($cmd!='p'))
      readline_add_history($cmd);
    list($do,$args) = parseCmd($cmd);
    if($cmd=='n')
    {
      if($linenr==count($out)) echo "This was the last line.\n";
      else {
        $linenr++;
        $line = $out[$linenr-1];
        echo "Line $linenr: $line";
        readline_add_history($line);
      }
    }
    if($cmd=='p')
    {
      if($linenr==1) echo "This is the first line.\n";
      else {
        $linenr--;
        $line = $out[$linenr-1];
        echo "Line $linenr: $line";
        readline_add_history($line);
      }
    }
    if($cmd=='r')
    {
        $args = $out[$linenr-1];
      if($linenr==count($out)) echo "This was the last line.\n";
      else {
        $linenr++;
        $line = $out[$linenr-1];
        echo "Next $linenr: $line";
      }
    }
    switch ($do)
    {
      case "quit":
        fclose($fp);
        exit(0);
      case "help":
        foreach($commands as $aKey => $aCommand)
          echo "  $aKey\t$aCommand[desc]\n";
      break;
      case "helpg":
        foreach($commands as $aKey => $aCommand)
          echo "  $aKey\t$aCommand[desc]\n";
      break;
      case "gcode":
        if(ereg("G([0-9]+)[^0-9]?.*$",$args,$regs))
          $G=$regs[1];
        echo "GCode: ".$args."\n";
        $reprap->gcode($args);
      break;
      case "absolute": $reprap->gcode("G90\n"); break;
      case "relative": $reprap->gcode("G91\n"); break;
      case "newhome": $reprap->gcode("G92\n"); break;
      case "fan_on": $reprap->gcode("M106\n"); break;
      case "fan_off": $reprap->gcode("M107\n"); break;
      case "unit_inch": $reprap->gcode("G20\n"); $unit = 'inch'; break;
      case "unit_mm": $reprap->gcode("G21\n"); $unit = 'mm'; break;
      case "home":
        $args='G1X0Y0Z0';
        echo "GCode: ".$args."\n";
        $reprap->gcode($args);
      break;
      case "speed":
        if($unit == 'mm')
          $speed = 10.0*doubleval(readline("XY Speed (2.5-80 cm/s): "));//25 - 800 mm/s
        else
          $speed = doubleval(readline("XY Speed (1-30): "));
        $reprap->setG1speedXY($speed);
        if($unit == 'mm')
          $speed = 10.0*doubleval(readline("Z Speed (0.25-1.5 mm/s): "));
        else
          $speed = doubleval(readline("Z Speed (0.01-0.50): "));
        $reprap->setG1speedZ($speed);
//         echo "Result: ".fgets($fp)."\n";
      break;
    }
  }
}

function parseCmd($theCommand)
{
  global $commands;
  if(ereg("^/(([a-z])[a-z]*) (.*)$",strtolower($theCommand).' ',$regs))
  {
    $firstChar = $regs[2];
    $cmd = $regs[1];
    $args = trim($regs[3]);
    foreach($commands as $aCommand=>$cmd_props)
    {
      $aCommand=strtolower($aCommand);
      if($cmd==$aCommand)
      {
        $do=$cmd_props['do'];
        break;
      }
      if((strlen($cmd)==1) && ($aCommand{0}==$cmd))
      {
        $do=$cmd_props['do'];
        break;
      }
    }
    if(!isset($do))
      echo "Command '$cmd' not recognized.\n";
    return array($do,$args);
  }
  return array('gcode',$theCommand);
}
function autoComplete($partial)
{
  global $myAutoComplete;
  return $myAutoComplete;
}
class RepRap {

  function RepRap($dev)
  {
    $this->changeDev($dev);
//     $this->g1speedZ
//     var $this->g1speedXY = null;
  }

  function changeDev($dev)
  {
    if(file_exists($dev))
      $this->dev=$dev;
    if(file_exists("/dev/".$dev))
      $this->dev="/dev/".$dev;
  }

  function setG1speedXY($speed)
  {
    $this->g1speedXY = $speed;
  }
  function setG1speedZ($speed)
  {
    $this->g1speedZ = $speed;
  }

  function gcode($str)
  {
    if((substr($str,0,2) == 'G1') && (!strpos($str,"F")))
    {
      if(strpos($str,'Z'))
        $str = trim($str).'F'.$this->g1speedZ."\n";
      else
        $str = trim($str).'F'.$this->g1speedXY."\n";
    }
    $safe_args = escapeshellarg($str);
    $dev = escapeshellarg($this->dev);
    `echo $safe_args >> $dev`;
  }
}
?>

Friday, September 19. 2008

RepRap: Rotary encoder Posted by Erik de Bruijn in RepRap at 23:20

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RepRap: Rotary encoder

Something I almost forgot to share is the optical encoder disks. I made those when Chris made his achievement on the encoder. The encoder on the extruder is an important step towards better 3D print quality (constant plastic flow rates).

Chris' encoder wheel
Source: hydraraptor's blog

To prevent a chicken and egg situation where you can't print an encoder wheel with an adequate quality and can't gain quality because you don't have one, I designed a wheel that could be printed on transparencies:

Two encoder wheels with different resolution. To be used for quadrature encoding.

Here's the source code (it's pure SVG). Of course it is usable for other parts of a RepRap and other robotics projects than the RepRap... so go ahead. If you make one in a different resolution, please send it back and I'll update my pages as well.

Friday, September 19. 2008

RepRap = also a milling machine Posted by Erik de Bruijn in RepRap at 20:18

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RepRap = also a milling machine

I just visited a conference about the launch of GPLv3. There was a very nice ambience. People I talked with were very interested in the possibility of the RepRap, and about it being a project under the GPL.

The Dremel(TM) toolhead

As everyone related to the project has envisioned, the RepRap will become a very versatile machine! Not just because they expected this, but because all of us had different plans with it. I wanted to actually mill PCBs... and this now seems very possible. The RepRap's standard toolhead is for extruding plastic. Nice to have to make many useful things. There are several things it's good at. It can make things that are not possible with the industrial standard of injection moulding. In terms of shapes it can create a hollow object consisting of one part. It can contain other components if its assembled during build. It could potentially reinforce the plastic with glass fibers, ceramics or a metal frame (to make for a composite material), this makes it stronger than any plastic moulded object could ever be. It could vary in color and still be made in one piece (adding the color pigments CMYK-style) as we extrude it, etc. Using edding markers of various colours this seems likely to be possible. But a lot of testing needs to be done (as always!). In summary, A lot of posibilities for plastics.

But still... sometimes the material requirements require something other than just plastics...

We needn't stick to using plastic. If we want to be able to use any wood, metal, sheet material it would be nice to be able to mill or engrave those using digital models! This is what I've been working on for the last two days. Here are some more pictures:

Milling more!

My first RepRap engraving/milling result!

I ended up writing the GCode parser and control software myself. The ReplicatorG actually did a good job, but it wasn't transparent to me what it did. Yesterday, after an evening of coding I could interpret and tidy up G-Code on the fly, control the machine from my program and do this in an interactive way. It has a command line with aliasses for G-Codes, and smart AutoCompletion and a history of entered command. I intend to release this code soon. Amazing what a modest 200 lines of php code can do

Mechanically, my innovation is to sharpen my milling head through automatically moving it to a position where a sharpening block is placed. Initial tests showed that this made it sharp and pointy. If this proves successful, you can use a 50 ct. drill instead of a 10 euro tungsten carbide milling bit. It can automatically be kept sharp so it might outperform one that wears out slower (in terms of price/performance). Besides, I don't want to spend the money if this doesn't fail. I've bought enough things 'just in case I need it' already

I intend to automate the process from Inkscape to actual workpiece and make it more transparent and user-friendly. But I have to go through the tedious manual process a couple of times to see HOW to do this in the best way. Perhaps I'll make an interactive (AJAX) graphing app that can also initiate the machine control and visualize where it is in real-time...

We can only see a short distance ahead, but we can see plenty there that needs to be done.

-- Alan Turing

Thursday, September 18. 2008

(AVR-)Dude, Arduino crashes fixed! Posted by Erik de Bruijn in RepRap at 13:23

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(AVR-)Dude, Arduino crashes fixed!

In anticipation of new thermoplast extruder parts, I built a Dremel toolhead for my RepRap. It should be able to do light milling, such as PCB isolation routing!

I was hoping to do some milling. But the G-Code firmware had problems, it kept crashing when I sent G-Codes. I've been debugging the firmware for quite a while. When I was just starting to go crazy, Wade (from the RepRap community) pointed out that it could be a compilation problem of ubuntu's AVR compilation toolchain [edit] Is fixed on Ubuntu Intrepid (8.10), so this problem will soon be irrelevant![/edit]. And that was it... all this time it wasn't a program bug, it was a compiler bug! The windows version of the avr-toolchain produced HEX code that DID run well! Here's how I did it:

I used the Arduino software to compile the v.1.3 G-Code firmware (as described here). Recompiling it on Windows in a VM (I don't have windows computers around) created a ROM file. After some searching I found that it saves ROM files in a file named:
C:\Documents and Settings\erik\Local Settings\Temp\build?????.tmp
Make sure you don't exit the arduino software, or the build will be gone!
Since I can't connect to the Arduino from windows (FTDI drivers won't install, device remains unrecognized), I transfer the .HEX file to Ubuntu again. There I downloaded and installed AVRDUDE, an open source package to program AVRs such as the one Arduino is based on. This is how I programmed it:

$ wget http://download.savannah.gnu.org/releases/avrdude/avrdude-5.5.tar.gz
$ tar xzf avrdude-5.5.tar.gz
$ cd avrdude-5.5/
$ ./configure
$ make
$ sudo make install
$ cp ../windows-compiled/GCode_Interpreter.hex ./
$ ./avrdude -p m168 -c avrisp -P /dev/ttyUSB0 -b 19200 -F -U flash:w:GCode_Interpreter.hex
avrdude: AVR device initialized and ready to accept instructions

Reading | ################################################## | 100% 0.05s

avrdude: Device signature = 0x000000
avrdude: Yikes! Invalid device signature.
avrdude: Expected signature for ATMEGA168 is 1E 94 06
avrdude: NOTE: FLASH memory has been specified, an erase cycle will be performed
To disable this feature, specify the -D option.
avrdude: erasing chip
avrdude: reading input file "GCode_Interpreter.hex"
avrdude: input file GCode_Interpreter.hex auto detected as Intel Hex
avrdude: writing flash (11684 bytes):

Writing | ################################################## | 100% 8.84s

avrdude: 11684 bytes of flash written
avrdude: verifying flash memory against GCode_Interpreter.hex:
avrdude: load data flash data from input file GCode_Interpreter.hex:
avrdude: input file GCode_Interpreter.hex auto detected as Intel Hex
avrdude: input file GCode_Interpreter.hex contains 11684 bytes
avrdude: reading on-chip flash data:

Reading | ################################################## | 100% 8.78s

avrdude: verifying ...
avrdude: 11684 bytes of flash verified

avrdude: safemode: Fuses OK

avrdude done. Thank you.

No no no, thank you, AVRDUDE!

Wednesday, September 3. 2008

PIXEL: The movie (our cute little cat!) Posted by Erik de Bruijn in Private at 16:00

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PIXEL: The movie (our cute little cat!)

We've adopted this cute little cat. We call him PIXEL. We liked the name, perhaps because pixels are small they can be fun to look at? When he grows bigger we could always change the name to megapixel...

Click to play

I found a nice open source package to edit the videos into a nice compilation.

Pixel is a very special cat. Apart from being able to fly, he can make funny noises, and in general be very cuddly.