Anyone here actually design PCBs and build prototypes?

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Jeff7

Lifer
Jan 4, 2001
41,596
20
81
Lots of great info there. Thanks!

1) Is there a way to make your own solder mask?

2) What could I use to display the SCH (schematic) and LIB (library) files?
From: http://www.crazynation.org/GC/GC_DD_INTERFACE/PROJECT_FILES/SCHEMATICS/
1) Don't know, though I don't know if it'd be necessary for this sort of thing. I've never even seen how they're made professionally.:(

If you're at least looking to gain some FPGA experience, and learn about them, I'd still suggest looking at the development boards that NutBucket suggested. They've already been laid out, and they're designed with the intention of allowing an engineer to evaluate the capabilities of the chip. Some of those Digilent boards are <$100.

Have you ever used circuitboard layouts before? If it's your first time, you are going to make mistakes the first time around, unless you're only wiring about 10 components together. ;)

That's one nice thing about doing boards at work - the first prototype of a new board is done on our board router, and the cost there is very low, especially compared to out-of-house boards. And since the traces are all bare copper, it's easy to solder in new components or wires as needed, in order to refine the design. (That's about where the positive points end though - some of the routed sections leave whiskers of copper here and there which can cause shorts, and there's no through-hole plating.)


Seems silly though. Schematic is what's important. Any monkey can do a layout :p
Though it can be fun to watch EAGLE's autorouter try to figure out anything. Sometimes it can be very quick and do an ok job, but most of the time, I've found it to be as capable of pathfinding as a blind rat that's missing its whiskers and 3 of its legs. :D

In some situations, it routes one trace, but then instead of moving that same trace about 0.1" to the side, it'll route the next trace aaallllllll the way around the perimeter of the board, in order to connect two pads that are less than a half inch apart.

Also, I've read things about ground return paths and so forth, especially where analog signals are being used, and being careful about certain things in high-speed digital circuits.

Incidentally, might you have any recommendations for (relatively inexpensive) books on this sort of thing? This set of books sounds like it'd be terribly useful.....and I had another book in mind, but can't find the link now. I think this is it.

For the basic stuff I do, the snippets I know is adequate, but some of our more advanced projects are starting to require things like ensuring that traces are of perfectly equal length, or else timings start to get screwed up. Granted, I'm not likely to get assigned to those sorts of projects, but I figure it's good (and interesting) stuff to know.
 
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Jeff7

Lifer
Jan 4, 2001
41,596
20
81
Jeff7,

Check this out for plated through holes:
http://www.lpkfusa.com/rapidpcb/throughholeplating/proconduct.htm

It's one of the solutions we use if the board has a lot of through holes. For most boards we use these:

http://www.circuitmedic.com/products/plated_hole.shtml

Basically a copper rivet you press in place and solder.
Most of our routed boards are single-sided anyway - they try to do that as much as possible just so that there's no requirement to flip the board and make sure it's perfectly aligned. The two-sided boards are usually controllers, and when they're routed, they're always just prototypes. Vias there are soldered by hand.

Those mechanical vias, punched or pressed in place, would probably be cheaper and quicker, and just about as effective, I would guess.....but holy crap that's expensive for a little press.

Sure looks handy though. :)
 

NutBucket

Lifer
Aug 30, 2000
27,152
635
126
You don't need the press. The basic kit comes with hand tools to press them in and its more than adequate.