This is just a 'sketch' of the process. I'll try to polish it
up... if enough people email to say they found this a useful
start.
This covers doing a single sided PCB. You can use the same
techniques to do double sided boards, but 'through plating' is
tricky... provide connections between the two sides with holes into
which you will solder short wires, or buy the little pins made for
the purpose (called 'vias')
Draw schematic.
Draw PCB artwork, as it appears on the tracks side of the PCB.
Use computer cad (see below) or pencil on 0.1" grid graph paper.
As each element (component and connection) of the schematic is
added to the PCB, use a highlighter pen to 'cross it off' on the
schematic.
Tape the schematic to the PCB.
With special tool, well worth buying, 'prick' the board
wherever a hole will be needed. The tool is a pin-prick device
with a spring loaded handle. You put the tip carefully just where
the prick is needed, then press down. The spring compresses up to
a point, then releases, effectively 'tapping' the head of the pin
prick device as if with a small hammer.
Mark onto board wherever you'll want copper at the end with
the special pens made for this. ('Etch resist pen')
Dry thoroughly.
Immerse in warm ferric chloride solution (dangerous, by the
way), agitating gently, until exposed copper gone.
Clean off etch resist ink. Trichloroethane... by it, or
something equivalent, where you buy the etch resist pen.
Drill holes. Again, special tool well worth the expense...
small hand-held electric.. doesn't need to be drill-press type.
Bits wear out quickly with fiberglass boards, by the way.. buy
plenty, in two sizes.
Polish with fine wire wool.
Enjoy!
The next step is soldering, of course. The magazine Everyday
With Practical Electronics provides a tutorial on that topic. (It was in the "Resources" section 6/06... lower left.)
Computer aided PCB CAD: I've used Easy PC from Number One
Systems through a long series of development. The Windows product is
expensive ($975,last time I looked), but it does do a beautiful job.
You start with a schematic, created as if using a very superior
'Paintbrush'. You then click on a button and it converts the
schematic to a preliminary automatically routed PCB design. You then refine the design by dragging
the components around the screen and re-routing the tracks, all using
rubber-banding (quite fun!) until you've got a layout you like. You can add components to the library. You can manage your parts lists and stock inventories as well. (They also have software to simulate your circuits from the design files.)
As I say, it is a beautiful product, but perhaps beyond the budget of my typical reader... I was lucky to buy my first copy when the company was starting, and they have been very fair about upgrade prices. I didn't need to upgrade, but the prices they've charged encouraged me.
Happily, there is an alternative: EZ-Route, a much less expensive program from http://www.ezr2000plus.com/. I haven't used it myself, but it is said to work well and be
user friendly. Once upon a time, the demo would allow you to do everything but save and generate Gerbers. (That may or may not be the case these days... but I'm sure that there's some sensible compromise between your hopes and the supplier's interests.) You can plot to many different printers/ plotters. It runs under Windows XP, and the website says "see readme file before installing on Win 95/98 or ME/NT/2000 machines, so I presume it is possible, with some minor hassle or limitations. The earliest versions of the program go back to the DOS era; it has been continually extended and refined since beginning in 1987.
At 11 June 06, there is a rather enticing notice on the webpage. I hope you see this in time!....
"Over the years, versions of EZRoute sold as high as $995 US and back to $695US. The upgrade cost for previous users was $195 US. When I was made exclusive distributor, I decided to offer EZRoute2000 at $195US for all users. This special price of $99.95US will only last until EZRouteStudio is released. Buy your copy now knowing that a special upgrade to EZRoute Studio will be offered to all EZRoute2000 users."
Consider stripboard ('Veroboard') or wirewrap as alternative.
(Latter for low power digital.)
And now: an 'unpolished' alternative re- explanation of much of the above. Someone wanted to know how to create PCBs from PCB designs out of magazines
or books.
----
Many mags offer a PCB service, which always seems like good value to me. Not only are the boards made to a good standard, but there's a chance that any errors which crept into the magazine are not present in the boards.
Beware photocopying the magazine artwork onto clear acetate and then proceeding with a photographic approach. The copiers sometimes distort the image. How much? How much is too much? All fine points you'll have to resolve for local circumstance. The worst problems will be with DIL socket footprints. Maybe use a piece of graph paper to locate the pinpricks which will determine where the holes get drilled. There are also special drafting acetates which are less prone to distortion. Are the worth it? Not sure.
I've heard that the magazine artwork can be used directly if you spray it first with WD-40 to make it transparent. Obviously, this depends on the magazine printing nothing on the reverse side. I also wonder about traces of the oil interfering with the etching process.
I heard of something called 'PNP Blue PCB Transfer'. I asked for a sample, even sent sae, but they declined... I can't tell you if it works well, as I haven't tried it. I believe you do a laser printer or photocopy copy (both subject to the distortion problems mentioned above) of your artwork onto this Blue Transfer stuff. (And I cannot promise it will go through your printer or copier without incident!!) You then iron the result onto a bare copper clad board. Peel the sheet from the board. The 'carbon' which stuck to the toner transfers to the board, and is the etch resist for the board's etching. This product was mentioned in Everyday With Practical Electronics. Supplied by Verkonix, 193 Green Lanes, Sutton Coldfield, West Midlands, B73 5LX, UK. Cheques to 'Verkonix Ltd', no VAT. At 6/99, 2 sheets, 11" x 8.5" incl UK postage: £6.00.
---
If you have access to a flatbed plotter, I believe you can buy plotter pens with etch resistant ink.
---
'Photographic' preparation of PCBs:
I've only done this once, so you can find more expert advisors, but for what it's worth:
In addition to the usual bits and pieces, you need:
A board covered with photo resist. You can buy this made up, or you can spray photo resist from a can onto a board.
'Developer'.. this, as I remember it, is merely sodium hydroxide. (A strong alkali... more dangerous to eyes than strong acids. Care.)
A positive image of the tracks you want on a transparent (best) or translucent (at least... I'm told that paper made translucent with WD-40 will work, but sounds pretty crude to me) medium. (More in a moment.)
A means of 'printing' the image onto the board. (Again, more in a moment.)
What you do...
(None of this, by the way, needs to be done in a photographic darkroom. Do minimize the photosensitive materials' exposure to bright light, though.)
Put the positive image of the tracks against the prepared board. The image should have black where you want copper at the end of the day. The 'black' needs to be opaque to UV light.. some photocopiers and laser printers leave you with a pretty 'thin' 'black'. There are service bureaus which will prepare gorgeous artwork for you from CAD files on floppy disc, though the time I did this, the combination of my software and service bureau meant that there were no drilling guide holes in the pad centers. Be sure you put the artwork on the board the right way 'round!
Now shine ultraviolet light on the board, through the artwork. Some people claim satisfactory results with sunlight... but I fear that approach must require a pretty good knack. Care: The UV bulbs made for the purpose emit light which is not good for you. Professionals use a purpose built device called a lightbox.
Immerse the board in the developer. This stage is rather like the ordinary etching stage. You can see the progress of the process, at least with the materials I used.
Wash... with care.. the etch resist material is delicate at this stage.
Proceed with normal etching and PCB fabrication.
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