Homebrew PCBs

> >andrewm1973@ wrote:
> >Have speced/thought out an interface to dump a BMP
> >file from a PC out to a laser

> Roger Lucas wrote:
> I am just starting to try to figure out BMP to raster
> for the PCB EDM MILL for which I have just finished
> the drive electronics <SNIP>

> Would be interested in your approach <SNIP>

> Are you dumping the BMP file to
> a separate micro or driving an interface direcly from
> the PC? <SNIP>

> To all who are interested in the progress of the PCB
> EDM MILL, I have produced a very simple clone of the
> Garden of Edm circuit, modified with some hints from
> Curt Richards (Curt are you still out there?).
 
> Just got to figure out BMP to Raster scan
> interpolation. If anybody else has any ideas please
> say.

Roger - Will you marry me :D

I so want to build an EDM for my machine shop.  I can't
bring myself to build a spark-oscillator one for moral
reasons (it doesn't have an Atmel in it).  Also the
garden_of_EDM looked too "thesis" project for me (here
is the idea, I am sure it would have worked if we had
more time to finish it)

It is another one of those "I will do it when I have
spare time" projects.  If someone else is going to iron
out the bugs in Garden_of_EDM and give me an RTFM
idiots guide I will be so happy.  I will also be able
to start my experiments to see if using stray cats as
a new form of dilectric has any merit :D

BUT to answer your questions.

I am dumping the BMP file to a seperate Micro.

There is going to be an ATMega in the laser plotter to
run the whole show.

I am going to try make it as universal as possible, not
stuck on Wintel machines. This is so people with other
computers like *nix, Amigas, RiscOS and VZ200s can use
it.  Even people that dont have computers and only use
macs could try it. (wonder if that flame bait will work)

The idea is to have the ATMEL sit on a seriel port, 
then you run some terminal software on the PC and
xmodem transfer the file to it.

The Atmel then turns the BMP file into a series of
dots.  I guess it would be easy enough for you to
adapt it to burn holes with a spark rather than pulse
out a laser.

I was going to use TIFF file format with G3 fax
compression instead of BMP.  On most PCB files you will
get about a 10:1 compression ratio with G3.  This
might be important if I do manage to get 2000 dpi
out of the laser.  The 1 megabaud limit of the FT232
chip I will use and a BMP would be a bottle neck.

I know I could use an AT90USB128 but that would
defeat the purpose of being free from writing any PC
software :D

The ATMega at 16Mhz should have pleanty 'nuff balls
to XModem, CRC, drive stepper, driver servo, drive
laser and decode G3-Fax without working up a sweat.

Worst case senario and I can't get an atmel to decode
G3 fax - I will hang my head in shame, do my own
RLE compression in software on the PC side and admit
to the world in general that pop-up-toasters do in
fact need 1 gighertz embeded Power-PCs.