Create a PCB from an image

The scan is a 300dpi "picture" of the board. With image processing tools I can get a view of JUST the traces...if that helps.

Are you aware of any PCB programs that will allow you to overlay your work on top of a picture? That might help me out.

This is a single layer PC board, so it is probably easier than some.

Thanks for the suggestions on home grown PCBs. I have done that before, but Its not "easy" enough for what I want. I need to be able to easily make these without effort, and the S100 bus card is by far the simplest. Others will be double sided.

Yes, I meant single sided. :) I can get a copy of the BUS card posted here.

I have used a PCB program called WinQCad, Protel, CircuitMaker, etc. Correl draw can trace an image into an HPGL. Is there any chance that I would find a DXF or HPGL to gerber converter?

Thanks, Grant

If you have a laser printer or a copier, there's a technique where you can take an image of the artwork, either print it on a laser or print it on a dot-matrix and copy it in a copier, and iron it on to the board and the toner becomes your resist.

See if you can find a board house that will accept negatives, and print the artwork precisely 1.000:1.000 on transparency film, and have them do that.

Single "layer"? Do you mean single "sided"? In S-100?? You just mean "not multilayer," right?

Good Luck! Rich

Is the 'scan' a 'picture' of the pcb ? If so it's only good for reference. To make a pcb you'll have to recreate the whole thing again from scratch.

Other than Gerber, some outfits may accept certain cad files directly or you could of course do it the way it certainly was back then and do a tape up.

Graham

So its either film or start from scratch. Are there good DXF to gerber converters? I'm just trying to find an easy to overlay the new design over the old.

Film and a drill pattern is what they used in the "old" days?

If it is to scale you can make one yourself pretty easily and fairly cheaply.

Press-n-Peel Blue

lets you print an image on a laser printer and iron it onto a blank PCB. I would first bring it into Photoshop to create a clean black and white (only) image. Don't forget to also "mirror" the image at this time if needed. Etch it with Ferric Chloride (from Radio Shack), drill with a Dremel using their cheap PCB bits. A "wash" with Liquid Tin (Allied Electronics) will protect the traces from corrosion and make it look much better. Use PnP again on the top (non copper) side for a silkscreen (it will be black). Do this before drilling otherwise you won't be able to iron the silk-screen image satisfactorily. Coat with Polyurethane or acrylic when done.

jj

I found that ViewMate includes the ability to import a bitmap. Does anyone have this software who could try and see if they could draw on top of the bitmap? Basically tracing the traces in the image?

The Free version of ViewMate does not allow importing bitmap images.

If it's single sided can you etch from the image you have? (possibly enhance it a bit in a photo-editing tool like the Gimp (gimp.org) or photoshop se (Adobe.com) it's not like you need plated through holes, and there's no alignment issues...

another option may be printing it out on transparency film (possibly enlarged a bit) and taping it to your monitor and then re-entering it into a PCB editor. :)

It's computationally difficult to convert raster images to vector (outline) images, and even harder to convert them to stroked images. guess which you have and which gerber files are.

Bye. Jasen

The 'language' of gerbers is something special. The idea of gerber conversion from a jpg ( or anything else ) is a non-starter. You need a program that is designed to output gerber data. Other than that the traditional film approach is the best idea.

Graham

As I tried to explain there isn't a simple 'conversion'

Gerber is based around commands that flash light onto a photosensitive film.

Manual tape up. Followed by photographic reduction. Drilling for small quantities was manual.

Graham

Yeah! When we were their age, we didn't even have computers! And we had to walk to school 40 miles through 8' of snow, uphill both ways, barefoot! ;-)

Cheers! Rich

I'm not that old. ;) I've found quite a few places on the net that do PCB scanning to gerber file conversion. If the price isn't too bad then I'll do that. I have to factor in my time involved. If it costs $200 to scan a PCB then I coudl work an hour over time for a week. ;)\\

- software/hardware manufacture - This web page has instructions for a BMP to gerber conversion, much more work than mailing the boards to be scanned. ;) - these guys don't have the best grammer on their site...could be scary to send them an origional card!

I guess the next step is to ask around on usenet who has used one of these services, what it cost, and how happy they were with the results. I'm set on making the process automated, that is e-mail a file and get a board, because otherwise the "project" becomes making boards. ;)

Any ideas on good groups to ask?

Thanks,

Grant

DXF is a vector format - it gives outlines of all the dark areas, AIUI gerber uses the centerline.

I don't know that converting outlines to centrelines is any easier than converting bitmaps to centrelines.

Bye. Jasen

Corel Trace (and, I'm sure, other similar apps) can do a trace "by centerline." Tried it out just for grins with a Postscript created by pcb (from the gEDA family) that I converted to a black'n'white bitmap by importing it into Corel Draw.

The centerline trace actually looks pretty reasonable when the results of the bitmap -> vector are brought back into Corel and the line widths adjusted appropriately.

Corel can save the result as a .dxf file and there are some dxf to Gerber translators out there (according to Google; haven't tried any). So it's possible in principle to go from a bitmap to a Gerber via a few intermediate steps.

I'd be concerned about all the misalignments along the way, though.

The OP's best bet is still probably to load up a board layout package and create "real" Gerbers. Having a working original board to duplicate should make it go quickly.

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Rich Webb   Norfolk, VA

hmm, it was about 15 years ago that I last played with corel trace,

if a grid was set at 0.1" would that help?

yeah, probably more time has been spent talking about it.

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Bye.
   Jasen

I'd forgotten that I had it. ;-) IIRC, it's now a standard part of the "Corel Draw" set.

Probably not. Many types of individual components are 100 mil pitch but may well be placed onto a finer grid. Traces almost certainly weren't on a 100 mil grid even back in the day.

Try printing the result of (bitmap -> centerline trace -> Corel vector

-> dxf -> Gerber) on a transparency and overlaying it onto the original. If it looks like it's good enough then it might really be so.

The gEDA suite is free and works pretty well (at least under Linux; I haven't tried it on Windows). If you're ever planning on making additional boards, you'll need it (or something like it) anyway. Recreating a "known" board is a good first project.

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Rich Webb   Norfolk, VA

These are the boards I will be copying. I plan on desoldering all the components, getting the board art duplicated, and then reassembling them.

In the spirit of getting as much data as possible I will be digitally x-raying the cards too. The x-rays should make debugging easier since you can easily see which traces go where via the vias. ;)

Here is a quick and dirty shot of a 68000 chip. The ram chips are in the top and the PROM are visible in the lower left:

Here is the RAM section:

For the altair boards they will have no components installed for the x-ray and I will have adjusted the levels of the picture to provide less contrast than the above pictures.

A nice thing about the Altair I found is that it came with a complete set of documentation. I bought it from the 2nd owner, and he has had it in the basement since 1981 when he got it.

Looks like fun! Good luck -- and also check the 'net for assorted schematics. A quick check shows that you might be able to find some out there.

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Rich Webb   Norfolk, VA