From Schematic to PCB -- How do you do it

[ethniccheese]

How does everyone go from Schematic to those pretty PCB layouts?  I know you can use tools like OrCAD (which is prohibitively expensive and difficult to use), but I don't think everyone uses expensive software to do it.  I have a hard time knowing where to start if I'm drawing the traces from just looking at the schematic.  I usually end up missing a few here and there.

[Peter Snowberg]

I don't etch my own boards anymore for a number of reasons, but I still do all the layout. I have used the services of ExpreccPCB a bunch of times and have been very happy with the results (surface mount parts, plated through holes, double sided boards, solder masks).

The really cool thing about ExpressPCB is that they give you some pretty decent free CAD software for layout. (if you use Windoze) It's very easy to learn and amazingly powerful for a free program. It isn't perfect, but it works for 99+% of what I do.

http://www.expresspcb.com/

They have a "proto service" that will give you three boards of 2.5 x 3.8 inches, 2 sides with plated through holes, for $66.65 (shipped to California). It may seem expensive, but if you make your layouts small, you can fit a few in that space and then you get three copies. I cut them out with a table saw or dremel. Tin snips will also work fine if you leave .2" between the designs and then file down the edges to make them look pretty.

When you factor in the cost of setting up (dishes, air pump, heater, etchant, press-n-peel transfer material, laser printing, etch resist pen, drills, and blank PCB), and then add the cost of reject boards and most importantly for me lost time, the ExpressPCB deal becomes a real bargan. Plus, you don't any toxic waste left over, they recycle the copper they etch off, the boards come coated with tin so they last, and you can also use trace sizes that you could never get away with if you etch your own.

The only downside to them that I have found is that you cannot export your layouts to another CAD program or use another board house with their software.

I still recommend them 100%. Dozens of boards, fast service, and never a single problem.

Like playing music, the most important way to get the hang of it is to practice until you get a feel for it. Your inspiration will take you from there.

Take care,
-Peter

[gez]

From schematic to ugly layout you can do the following:

lay out your components on graph paper and make little crosses where the holes are to be drilled.  Photo copy it and make a little 'map' showing which components goes where and draw thin lines where the traces connect from hole to hole.  

Using another copy, tape it to the surface of your board and drill.  Once done, peel it away and use a ferric resistant marker pen to join the dots on the board, following your map as a guide.  Stare at it for a good few mins and work out where you can make the traces thicker.  If you make a mistake just use an ear bud and solvent to clean off the ink.

For more than one board, place a transparent sheet over the finished board and go over it with a pen, then use the sheet with photo board to make as many copies as you like.

You can buy transfers with pin outs of ICs which can be used for the detailed bits.  I like this method as I hate learning how to use new software, plus I can make traces really large and odd shaped, round off all the corners etc - the whole thing looks 'art nouveauxish' when finished!

[nightingale]

hello~
i learned from RG's PCB book... very good info...plus he binds them in his garage... check his site: www.geofex.com
hope this helps,
~ryanS

[ExpAnonColin]

I've tried CAD programs, but we just weren't compatable.  I'm on OSX so I use PCB warrior.  It's just too galdarn hard to make sure all the holes are the right distance apart for ICs, transistors, pots and the like.  I think I'll stick to premade boards like these:


Works just fine for now.  Is there anywhere that I can send my drawn and scanned PCB layouts and have them make a few (maybe 10-20) of them for me?

-Colin[/img]

[bwanasonic]

The really cool thing about ExpressPCB is that they give you some pretty decent free CAD software for layout. (if you use Windoze) It's very easy to learn and amazingly powerful for a free program. It isn't perfect, but it works for 99+% of what I do.

I don't don't even etch my own boards, but I find the combination of ExpressSch and ExpressPCB very useful even for my perf layouts. I draw/redraw the schematic in SCH and when I go to PCB, it helps remind me what goes to what, and generally adds to the *idiotproof* factor. What would you consider the lower limit of complexity where having boards made is cost effective? I'm still working through the evolutionary stages of FF/Rangemaster/ O Squeezer/ Mosfet Boost, and now the Tycobrahe Octavia. I still don't feel I've reached a point where etched PCBs are worth the hassle, and I don't I have any circuits I could really call *my own*. When I design something original is when I'll start looking seriously at getting PCBs made.

Kerry M

[Marek]

an example:

http://wind.prohosting.com/tpabap/od1.html

M.

[Mark Hammer]

Although I rarely, if ever, design my own boards, I do have a copy of RG's book on designing PCBs for pedals, and it's very good. He really has become a marvelous technical writer over the years.  It also includes layouts for some favourites as tutorial examples.

There are a great many circuits that are essentially just as easy to make on perfboard as with a PCB.  A lot of them are simple boosters or distortion devices.  Once you get beyond that, however, perfboard starts to become a nuisance, or at least requires just as much planning to avoid clutter as planning out a PCB.  The other nice thing about PCB's is that once you have a layout, if someone says "Jeez I love that pedal", you can just sell/give it to them, knowing that it is a trivial matter to throw another board together from the existing layout.

Part of what the PCBs offer, on top of ease of wiring is mechanical stability, since all components are effectively secured to the board.  If you don't want/need to design/make a PCB, then the pad-per-hole boards provide a nice compromise since they allow you to secure components to the board via the pads.  The other nice thing is that the alphanumeric grid they use makes it possible to easily keep track of what goes where.  Great for when you get interrupted.

Radio Shack sells them, as do many oher commercial providers.  I have to put in a plug for the ones that Steve Daniels sells at Small Bear though.  He sent me some samples and these kick the ass of the RS boards around the block and down the stairs.  Much much higher quality, and available in a variety of sizes, both single and double-sided.  A pleasure to work with.

[ethniccheese]

Thanks everyone for your help.  The article Marek posted was of a lot of help and I intend to try creating the layout first and then going to pad-per-hole board if/when I get too frustrated.  I really appreciate your help.

[ErikMiller]

Surprised that nobody has chimed in with EagleCAD. That's my favorite, although I haven't used the schematic capture part, just the board layout.

They have a freeware version, and a reasonably priced Light version.