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A Hardware Threepack
Johnath writes: "This just happens to be a great time to be a hardware junkie. For those interested in learning more about the metal under their PC's hood, Tom's Hardware has a great intro to PCB manufacturing, Ars Technica has recently written an architectural study of the P4, and ExtremeTech has a decent look at the South Bridge." The circuit board article is really good - explains it better than the textbooks I've seen.
I think Tom even said it himself:
It's just been a S-L-O-W period in hardware news. The excitement of MP Athlons has subsided, the P4 scene is quiet, the GeForce3 has been out for a while... Honestly, is there anything NEW happening in the hardware world? (Aside from future releases...)
Ian
Yeah, unless you'd actually like some competition in the video card market.
You can buy NVIDIA, or NVIDIA. But hey, there's also NVIDIA! Oh, did I mention NVIDIA?
Free Hans!
Tom's Hardware has a great intro to PCB manufacturing
That was a great intro, well written, and explaining the basics. Not so basic, however, is attempting to make your own PC boards.
It's easy once you've got the practice, and you can get all the stuff you need at Radio Shack (or better places).
Toner transfer is my method of choice. I stuck transparencies, like you'd use in an overhead projector, into my laser printer. I crank up the darkness of the page, so it puts a lot of toner onto the transparency.
Then, I print my board layout, in mirror image, onto the transparency. Rest it on the blank, clean copper-clad board, and run a hot steam iron over it for a few minutes. With some practice, you'll be able to transfer enough of the toner onto the board that when you etch the blank board, your layout comes through.
I've even managed to produce double-sided surface-mount boards for prototyping and testing the high frequency response of a radar video processing system using this technique, before we committed to actually having the boards mass-produced.
Two sheets of transfer sheet, toner side in, aligned very carefully and stapled together, then a nice long pressing.
He thought I was crazy, but I was able to confirm to my boss, before we shelled out $50,000 for the manufacturing run of PC boards, that the layouts we'd designed worked properly.
Multilayer boards, like modern computer components use, are impractical for do-it-yourselfers to attempt, but I once built a 4-layer prototype by carefully aligning two double-sided boards, made as above, over a third (blank, no copper) board, and screwing the whole sandwich together with machine screws. Carefully-installed plate-through holes were accomplished with scraps of wire soldered through. It took four tries before I got the alignment right and made the board useful for building the prototype.
If that sounds complicated, you should see how stuff was built before Westinghouse invented printed circuit boards. Imagine a modern computer built like that. Urk.
All this and I'm still unemployed. Hit my page for my resume and stuff.
Fire and Meat. Yummy.
I have used Express PCB twice and have been happy with their quality and response time. They have a free CAD PCB design tool available for download. This is great for small, do-it-yourself projects requiring better manufacturing than Radio Shack kits can provide. They create two-sided boards complete with vias.
What other services are available?
I have a really great quote, but I'm not going to tell you. -- me
I've done that before, but I found the results not-so-good. Then again, I was using those special transparencies designed for it.
Myself, I go a couple of steps further. I get the presensitised boards and print, using an inkjet printer (I found the Epsons *much* better than the HPs for this), on inkjet transparencies. I then create a sandwich of board, transparency, and some heavy glass on top. Expose to light (a cheap-o $20 desk flourescent has done me well) for a bit, drop it into diluted sodium hydroxide for a few seconds (drain cleaner will work in a pinch, but I don't really recommend that), wash, then etch. I've so far ethched only with ferric chloride, but I've been thinking about going ammonium persulfate, which is supposed to be quicker and easier to use, except that you have to heat it.
After etching, I simply wash with water. I don't bother cleaning off the remaining photoresist (green traces, cool). I simply spray the board with acrylic, drill using a Dremel (get the tiniest bit you can find!), scrape the acrylic off the pads with an X-acto knife, and solder it.
Yes, I'm one of the freaks that had a 'custom fishtank' made.
I've found the results to be extremely good. I've made boards with *really* thin traces and they've always came out perfect.
Of course, I'll have to chase that with some links:
(that lameness filter gets lamer all the time, arrgh)
A conformal coating is a thick, usually clear, protective layer that goes on after the components are inserted and soldered. It protects the board against water and other environmental hazards. Boards in computers usually don't get a conformal coating, but automotive, marine, and aerospace electronics usually do.
You can get conformal coatings in spray cans and do it yourself, which can be useful if you're building electronics that has to survive wet environments.