How does process color work

[vacpress]

Im working in win XP, but i may try and make the main software DOS based so i can use these www.halted.com 100mhz dx4 tablets as the computer on my machines. if not dos, win95 and an external pulse generator.

I am going to develop a website where interestedc parties can contribute to this project. has anyone got any server space? or should i just ask for a file area here? im sure cncadmin would be into it...

As for the software and stuff, i would really encourage everyone here who is interested to begin building a machine. if you need some steppers, REAL BAD, I will send you some. ive got many smallish unipolars, but they are fine for a prototype of this, as there is no real contact between the work surface and the equipment. like an inkjet, it can be built to just barely work well enough...

checkout www.luberth.com - he has an amazing array of pertinent info available. i like his Cstep program as a DOS GCode interpreter, as it has opensource, and a nice GUI, and will run well on a 486dx4 100.

For software. I am still evaluating options, but my first experiments will be:

1- design simple line drawing in a vector format - such as PS, HPGL, DXF, AI
2- load the postscript into Cstep - print a 1-color image.

Thats gonna be thefirst run

For the second round of experimentation:

1-Using photoshop convert a bitmap image into its 4 color components and save them as seperate files
2-Using BMP22Gcode, or any simiilar technology, i will make 4 seperate g code files.
3-Manually program the robot to return to start position after each Gcode file.
4-Run the file sequentially, changing the color ink\paint in the gun. this will result in a fairly horrible image

From here its a bit hazy, it seems like some sort of "GL" library is going to provide the answers though. I want the machine to simply go line by line like a normal inkjet, and i want it to have a painthead that can deliver a very small dot, not a spraygun. this will probably be the longterm goal. short term might be holding 4 airbrushes and printing very large color plots using HPGL language. im still not totally versed on how to handle color changes -hopefull HPGL can ahndle more than 1 color pen - i think it can. this eliminates the need to dd "return to home" commands in the gcode.

one reason i liek phgl at this point is that there is ALOT of homebrew work that has been done with it.

sugestions?

[vacpress]

Heres a link to a motion controller in a PIC. http://www.luberth.com/cstep/PStep.html

tachus42,
That, combined with your servo driver could result in a sweet little $15 package.

i would be very interested to hear more about the servo driver you created. the capacities, etc.

also worth noting, chagrin has written a preliminary perl program that will decode an image and prepare it for printing in 4 colors. we need to research dithering and other aspects of generating an image with pixels though, i think. i am also begining to devlop a virtual device to emulate the hardware so the software guys can see their results without the hardware.. this should be fun.. more to come, including a link to a webpage with the solidworks files, and a way for non SW users to view the thing in 3D, make measurements, see inside assemblies.

comments?

[tachus42]

Vac i can send you some sample files if you like just let me know where to send them.

I don't have ghostscipt installed on a windows computer only on linux but this should still work.

Start the add printer wizard
Select Local Printer
For Port Select FILE:
For Model try Tektronix Phaser 600 - a color PS Printer with Very Large Paper sizes.
There should be generic postscript as well but I just checked and couldn't find it.
Now when you print to this printer it will create a PS File.
Find the ras32.upp file and edit it inserting a resolution command - see the confusing link i posted earlier, set it to some thing resonable like 10 dpi.
Try some thing like this
ghostscript @ras32.upp -sOUTPUTFILE=OutputFileName -sPAPERSIZE=a10 PostscriptFileName -c quit
I have used a tiny paper size here to keep the out file small. Open it with a hex editor and take a look.
Here's the format of the header: http://gmt.soest.hawaii.edu/doc/html...s/node118.html

I'm half way through writing a script to convert this raster file to gcode - a trivial task but I'm still learning perl but I'll post it here in a day or two.

If you want to build a dedicated controller for you machine the tablet looks very attractive but wahat about Input and output ports? To add these might be just as complicated as building a controller based around a microcontroller and realtime stuff is alot easier to deal with without the overhead of a OS. I'm not a PIC fan and Prefer AVR's not only for the more powerful clean archtecture but also the free gcc complier. But a PIC should do just as well if that's what your famililar with.
If you want to print left to right and then right to left you will need anough memory to hold one scan line so it can be reversed this probably means you need a microcontroller with a small ram attached - not too hard. I'm not sure if any of the PICs support this in hardware, but you can allways just attach it to a standard port and drive it with software.
The other way would be to reorder the output on the computer with a small prog before sending it to the printer.
What output resolution are you aiming at? If you get to ambitious you might be waiting hours or weeks for a print.
Have you looked at model or hobby sites for airbrushes? They seem to make some very small ones but they are very expensive. Perhaps you could make your own, a venturie and a valve, you might be able to use the electrical valves used for garden watering systems with a bit of modification. They are quite cheap and have 12 volt coils I think.

[publitime]

vacpress


where to find the information about the pattents on the wirejet from pixation.
Does somebody know if it is possible to find pictures of the parts who are pattented.

[tachus42]

OK here is the Raster to GCode Converter pretty rough and barely tested but seems to work. I haven't put in the actual gcode yet but thats just a matter of editing the top part of the file.

#! /usr/bin/perl
{
# Put the GCode Snippets in Here

my $SetUpCommand="Set Up\n";
my $MoveXRightCommand="Move Right\n";
my $MoveXLeftCommand="Move Left\n";
my $MoveYCommand="Move Down\n";
my $CyanOnCommand="Cyan On\n";
my $CyanOffCommand="Cyan Off\n";
my $MagentaOnCommand="Magenta On\n";
my $MagentaOffCommand="Magenta Off\n";
my $YellowOnCommand="Yellow On\n";
my $YellowOffCommand="Yellow Off\n";
my $BlackOnCommand="Black On\n";
my $BlackOffCommand="Black Off\n";

my $buffer;

my $XPixels;
my $YPixels;
my @ScanLine;
my $XPosition;
my $YPosition;
my $ImageLength;
my $ImageDepth;
my $RasType;
my $MapType;
my $MapLength;

my ($InputFile, $OutputFile) = @ARGV;

open(INF,"<$InputFile") or die "\nCan't open input for reading: $!\n";
open(OUTF,">$OutputFile") or die "\nCan't open output file for writing: $!\n";
binmode INF;

read(INF, $buffer, 4); # read first 4 bytes and check for majic number 0x59a66a95 = 1504078485

if (1504078485!=unpack(N,$buffer)){die "Input does not look like Sun Raster\n";}
read(INF, $buffer, 4); # get width
$XPixels=unpack(N,$buffer);
read(INF, $buffer, 4); # get height
$YPixels=unpack(N,$buffer);
read(INF, $buffer, 4); # get depth
$ImageDepth=unpack(N,$buffer);
read(INF, $buffer, 4); # get Length
$ImageLength=unpack(N,$buffer);
read(INF, $buffer, 4); # get RasType
$RasType=unpack(N,$buffer);
read(INF, $buffer, 4); # get MapType
$MapType=unpack(N,$buffer);
read(INF, $buffer, 4); # get MapLength
$MapLength=unpack(N,$buffer);
read(INF, $buffer, $MapLength); #throw away Map

print "Image is $XPixels wide and $YPixels tall\n";
print "$ImageLength Bytes Long, $ImageDepth bits \n";
print "Rastype: $RasType, MapType: $MapType, MapLength: $MapLength \n";


print(OUTF $SetUpCommand);

while($YPosition<$YPixels)
{
print "Processing Line $YPosition \r";
read(INF,$buffer,$XPixels); #get one line
@ScanLine=unpack("c$XPixels",$buffer);
if($YPosition%2){reverse @ScanLine}; # if Y is odd reverse to print right to left
if($YPosition%2){print(OUTF $MoveXLeftCommand);}else{print(OUTF $MoveXRightCommand)};
for(@ScanLine)
{
if($_ & 1){print(OUTF $BlackOnCommand);}else{print(OUTF $BlackOffCommand);}
if($_ & 2){print(OUTF $CyanOnCommand);}else{print(OUTF $CyanOffCommand);}
if($_ & 4){print(OUTF $MagentaOnCommand);}else{print(OUTF $MagentaOffCommand);}
if($_ & 8){print(OUTF $YellowOnCommand);}else{print(OUTF $YellowOffCommand);}
if($YPosition%2){print(OUTF $MoveXLeftCommand);}else{print(OUTF $MoveXRightCommand)};
}
print(OUTF $MoveYCommand);
$YPosition++;
}
print(OUTF $BlackOffCommand);
print(OUTF $CyanOffCommand);
print(OUTF $MagentaOffCommand);
print(OUTF $YellowOffCommand);
close OUTF or die "Can't close $OutputFile: $!\n";
close INF or die "Can't close $InputFile: $!\n";
}

Dead simple really - a dumb microcontroller could handle this easily.

[sdfine]

Publitime,

Go to the US Patent office web site. They have all the images and text related to all patents. Pixation also has a ton of detailed pictures of the parts of their machine and how they work. It's all there, but it is his patented design.

Steve

[vacpress]

http://patft.uspto.gov/netahtml/search-bool.html <-patent search engine. i found the pixtion patents with their numbers, but didnt get frar reading them as their patent lawyer was fond of incomprehensible repitition of the same ideas. legalbabble is so obnoxious.

so. there is alot of info here now.. i gotta catch up!

[vacpress]

sdfine - we are, at least not me, trying to copy the pixation design for ANY commercial purpose - not even sign making. i just like a challenge, love art, and want to have a crazy gantry-robot thing that can do wierd stuff like do additive 3d part creation using a can of that expaning insulation foam..

or draw a path with a gelatenus gasoline mixture, and then at the end light it... so a big complex design gets burnt into a workpiece.. thats the vector part.

for raster, large format art generation, even if it isnt a real photorealistic printer or whatever is very intriguing to some people.. every big r&d project probably involves some reverse engineering to investigate the existing technology.. thats part of why patents are wonderfull - they provide the entire technical details of an idea, while protecting it. this allows innovators to profit from their inventions, and it allows future innovators to build on what has been done, and not step on the toes of the creator of that technology.


this is very idealized of course. i have no patents, etc, so im sure any patent holders here would be very angry at any word of their ideas being reverse engineered, no matter how academic the goals..

i would NEVER try and commercialize a pilfered design.

besides, i think a smaller, more efficient, less complex painthead can be developed. something that uses little 15-25oz/in steppers, simple halfstep 2803 drivers, wire or plastic hoops instead of long wires and tensioning systems..

i havent started on this. for now, the airguns will be fun to do. im sure its been done many times in professional R&D projects. this idea - using air to blow in\paint onto a work surface is as old as art. literaly.

some of the first lasceaux(spelling?) cave drawings, in france, show evidence of a person crumbling up charcol, and blowing it on the back of their hand with their palm against a cave wall. this has left outlines of human hands 20,000 some years old....

[publitime]

i'm just intressting in the technik from the wirejet.
I will build a cnc painter just for fun.
Past year i have build a cnc mill for milling pvc for doing nothing with the machine.
3 years ago i bought a cnc for 125.000 euro's from mastermill.
This machine i use for commercial purpose.
Building cnc is my only hobby.
Mostly i use the parts again to rebuild something else.
So the cnc painter i will build as a hobby and not commercial.
For commercial printing i have a vutex large format solvent printer at my shop.
Building is just for fun and learning how technics works.

[vacpress]

publi-exactly. i have access to all this stuff also. large format printers and good cnc equipment. i am mostly interested in the gantry for experimental art purposes. this thing, spinning on its axis, using random environmental inputs like audio and movement to make spirograph patterns in sand could be cool. or with a thick marker. or.. or. laying down layer by layer of insulation foam to make 3d sculptures. that could be the first reseach into large-format rapid prototyping. the design could go from something nasty and fun like foam to something precise and demanding like ABS pelets through a nozzle. i am sure something like that can be done on a diy scale. 20 years ago i doubt many CNC knowledgable people would have forseen rc airplane builders buying used linear motion components off ebay to build CNC machines in their garages - usually, it seems, much to the chagrin of their wives... hehhe. happily, i have no wife.

[publitime]

tachus 42

in what program you have write the controller?
Is it possible to use a PIC16F84A. microcontroller for the project.
What program do you use to assembler the program?
Is it possible to do it with MPLAB v5.70

[vacpress]

publitime - that is a perl script. there is a perl compiler for PICs. i think its free? maybe im confusing it with another product i know exists, a perl basic stamp. so, those would work, but you would have to add the file transfer stuff for serial port, and write a pc program to work the thing. MPLAB is mainly for Assembler code, which is much much different than that perl code. that perl code, about 50 lines is probably hundreds of lines of assembler code. assembler for pics is good at simple stuff. there is a free C for PICs asembler, and for higherend PICs, microchip has free C compiler.

i use picbasicpro for my pic stuff. right now my board is dead though = gotta get a replacement to program chips.