While I wait for my new audio power amp chips to arrive, I’ve started looking at making a custom PCB or two for BMOW’s various buttons, connectors, and jacks. I plan to use a pizza-box case from an old X-terminal that’s the perfect size, and already has case cut-outs for VGA and keyboard connectors, and other goodies. I could try to use all panel mount connectors with wires running back to the BMOW board, but some parts like the VGA and keyboard connectors typically only come in PCB-mount varieties.

I plan to design a simple PCB of about 1×5 inches, which will hold the various connectors, as well as the audio amplifier and related circuitry. It will be a long narrow board mounted in the back of the case, right next to the cut-outs, with headers for connecting cables internally back to the BMOW board. Of course I don’t really need to do this, but it’ll help make everything look neat and professional, and I’ve been looking for an excuse to design a PCB for a while. I know nothing at all about the design process, but I’m interested to learn. I will definitely keep this to a 2-layer or even 1-layer design, to keep it as simple as possible.

I wrote a little bit about some PCB manufacturing options in a comment to a posting last summer: /2008/08/17/wire-wrapping-pain . At this point I think I’ve narrowed the choices to ExpressPCB and their free, proprietary CAD tools, or the free version of Eagle PCB and Futurlec’s manufacturing service.

ExpressPCB looks very easy to use, and easy to submit designs, with very quick turn-around on manufacturing and shipping. That’s pretty important, because I’m notoriously impatient. Their “miniboard” package gives you three copies of a 3.8 x 2.5 inch board for $51 plus shipping. Unfortunately their software seems pretty basic, and its built-in library of components isn’t great. It also locks you in to their proprietary file format, with no easy way to export your design to other programs and manufacturers later.

Eagle PCB seems to be the standard tool for hobbyists making PCBs. It looks more full-featured, but with a steeper learning curve for newbies like me. The free version has a size limit of 8×10 cm (3.9 x 3.1 inches). Futurlec will accept Eagle files, and turns around orders in 7-10 business days. The cost for a single board comparable to ExpressPCB’s miniboard is $31, or $43 for three of them, plus shipping. They’re in Thailand, but were able to ship my last parts order to me in just two days, and it had some cool elephant stamps on the package to boot.

Given these size constraints compared to my desired 1×5 board size, I’ll probably try to design a board with half the connectors on one side and half on the other, and get two of them. Then I’ll put the two boards side-by-side with one rotated 180 degrees, and populate half of each board with the appropriate connectors. It’ll be two 3.8 x 1.25 logical boards sharing each 3.8 x 2.5 physical board.

I’m leaning towards Eagle PCB + Futurlec, but I plan to play around with them both for a while, and see what sticks. It should be fun!