Bean: Do you mind telling us who did your PCB?
cbmeeks
Posts: 634
Or is that secret?
The reason I ask is that I am doing something similar. Not for resell, but as you may or may not know, I am building my own personal computer.
I am trying to do a modular design. In other words, I want to plug in video cards (and audio, etc). So, once my video system is etched in stone, I want to put it to PCB.
Thanks!
cbmeeks
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http://metroidclassic.com
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DMCA Sucks
RIAA Sucks
The reason I ask is that I am doing something similar. Not for resell, but as you may or may not know, I am building my own personal computer.
I am trying to do a modular design. In other words, I want to plug in video cards (and audio, etc). So, once my video system is etched in stone, I want to put it to PCB.
Thanks!
cbmeeks
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http://metroidclassic.com
=========
DMCA Sucks
RIAA Sucks
Comments
I did the layout and PCBExpress (not expressPCB) manufactured the boards.
Bean.
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"SX-Video·Module" Now available from Parallax for only $28.95
http://www.parallax.com/detail.asp?product_id=30012
Product web site: www.sxvm.com
Available now... SX-Video OSD module $59.95 www.sxvm.com
"I'm a man, but I can change, if I have to, I guess"
Red Green
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Were you satisfied with them? Use them again?
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http://metroidclassic.com
=========
DMCA Sucks
RIAA Sucks
If you can make 1 of your boards using TTS or whatever to make sure it's correct.
Bean.
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"SX-Video·Module" Now available from Parallax for only $28.95
http://www.parallax.com/detail.asp?product_id=30012
Product web site: www.sxvm.com
Available now... SX-Video OSD module $59.95 www.sxvm.com
"I'm a man, but I can change, if I have to, I guess"
Red Green
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Jon Williams
Applications Engineer, Parallax
For example:
2 layer, 4 layer??
silk screening??
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http://metroidclassic.com
=========
DMCA Sucks
RIAA Sucks
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Jon Williams
Applications Engineer, Parallax
Given the choice, I'll always pick a 4 layer board, because it allows me to put power planes on the inside layers, or routing on the inside and ground layers on the top and bottom for critical systems, or 4 layers of routing with integrated planes for dense boards, or...
The main advantage over 2 layer designs is the possibility of increased density and better plane layout, which are often used together to remediate the noise that can crop up when things are packed together very tightly on a board.
The last option I can think of right now is for very high current circuits. I have one spot on a board that will be measuring current in excess of 100A, and I have the copper pours for the connectors and the measurement chip on all 4 layers, with no soldermask on the top and bottom so they'll be coated with solder during the solderwave process and have a little more metal to spread the current out in. Every little bit helps when you're working with BIG power.
Silkscreening is really really really nice to have, and I consider it only slightly less of a requirement than the ubiquitous green LPI (Liquid Photo-Imagable) soldermask. I'm big into labels, legends and notes. Permenant things like copyrights go into the copper layers (one mark on each layer, no grinding one off), along with things like part #s, logos, and things like that (usually on the top or bottom copper layers only). Connector pinouts, component outlines, serial number plate areas, and other things all go on the silk layer.
My $0.02
-dave
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This is not a sig. This is a duck. Quack.
Cool trick to put the copyright on the middle copper layers so you can't grind it off.
Bean.
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"SX-Video·Module" Now available from Parallax for only $28.95
http://www.parallax.com/detail.asp?product_id=30012
Product web site: www.sxvm.com
Available now... SX-Video OSD module $59.95 www.sxvm.com
"I'm a man, but I can change, if I have to, I guess"
Red Green
·
Since I work at a product development/consulting company, our work is almost always for other people. Part of the policy is that our copyright comes off (and the customer's goes on) only after the bill gets paid in full, which is also when we release gerbers, code, and any documentation that was ordered. It was a hard leson learned unfortunately. Our super duper in-house toys get the copyright on all layers (2-10 depending), hidden under the silkscreen on both sides. Part numbers and the website are put right next to it. Consulting is a nasty business sometimes, and you do what you've got to do. I'm working on obfuscating a design for a client right now that's really driving me nuts. Fake chips, phantom traces, bogus routing layers, fake connectors, the works. I've probably got 20 or 30 hours in and it's not even halfway done. Oy.
I've also been known to put some sneaky things into the inner layers, for fun, on projects where it wasn't a big deal.
Images of dinosaurs in PCB revisions of obscenely obsolete products, things like that. My favorite was an anti-riaa image that got snuck into an MP3 player board by one of the other guys here. It was about 2mm square and in the middle of a very dense bunch of traces, and to the best of my knowledge, still exists in the units on store shelves. I haven't cut one up to find out though...engineering doesn't pay quite well enough for me to buy things only to reduce them to rubble
-dave
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This is not a sig. This is a duck. Quack.
2. To render indistinct or dim; darken: The fog obfuscated the shore.
that sounds fun. laying out dummy ckts. can you make them secrety functional to serve a hidden purpose? something like a backdoor in sofware?
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engineer, fireman, bowler, father, WoW addict [noparse];)[/noparse]
The whole point of this exercise is to confuse the living hell out of a reverse engineer, so my 'dummy' circuits are indeed active parts, traces (with pulses), power dissipation, and other things that are on and function, but don't actually serve any purpose except to confuse and distort any information gathered.
There is actually quite a bit of misinformation in the code as well. Dummy functions that serve no purpose but to kill the system if a dummy part is removed, heavily obfuscated real functions, fully unrolled loops throughout, and dozens of dirty tricks I didn't even see at the code review on Monday (I program with solder, not software, at least at work).
It's really amazing. We'll probably end up putting close to 200 hours into obfuscation alone. I'm NDA'd so I can't say much else (and I've left some things out) other than the only way to make it harder to figure out without the design docs would be to custom-mask some ICs with their own obfuscation systems in the silicon.
-dave
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This is not a sig. This is a duck. Quack.
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John J. Couture
San Diego Miramar College
oic. well i atleast hope you get to be creative with your obfuscation because it seems like a great way to put a little personality into your layouts. but even that wont fool ben affleck. ok that was a really lame joke.
cbmeeks,
express pcb has a ~$60 offer for 3 small pcbs. since the software is free its definately worth one prototype design just to check out their service. and even if you you dont use their manufacturing service the expressSCH program is commonly used to generate schematics to share w/ other forum members.
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engineer, fireman, bowler, father, WoW addict [noparse];)[/noparse]
I actually dislike back doors if there isn't a strong argument for them (remote firmware updating or diagnostics are a good example, but they're usually handled with a little more finesse than a simple backdoor). They offer no increase in functionality, and generally compromise security and reliability. I have the same opinion about dummy hardware, and I do it at work is because the customer pays for it, and because obfuscation is fundamentally different from a secret set of hooks or a hidden API. My own projects are clean, simple and unencumbered. Occam's Razor applies here very well.
Then again, I don't do the kinds of things our customers do.
Nick-
I've met a dozen or so obfuscators over the years, and I can tell you that aside from the basic toolkit I mentioned here, there's a lot of personality put into each job. Given a half-dozen samples from eachto study, I could probably pick out the author of an unknown obfuscation pretty easily. That said, an an engineer who does occasional obfuscation, I try very hard to make mine look as vanilla as possible. The more that a product looks reasonably complex once I'm done, the better I've done my job. Anything that sticks out or causes one to notice it is a poor bit of work, because it will rapidly draw the attention of a reverse engineer to a part of the obfuscation that will allow it to be unraveled more quickly. I try to handle things with cleverness and finesse rather than bulk and security through obscurity (tho that is precisely what an obfuscator does in all practicality). And though I'm sure my work has a signature too, no one has ever noted that, and that makes me feel pretty good.
And Ben? He's a hack. A real reverse engineer of that level wouldn't ever agree to memory destruction. The things learned from other products are essential in reversing ever more complex and skillfully obfuscated things. It's like taking classes. You don't forget a 200 level course before your 300 level follow-on, do you? The entire premise bugged me a lot. They got the process all wrong.
-dave
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This is not a sig. This is a duck. Quack.
Post Edited (Dave Paton) : 9/29/2005 2:08:32 PM GMT
Because you don't use ExpressPCB that implies you use a third party software program for designing your PCB's. I tried PCB Wizard 3 ($50) but in order to actually make PCB's you have to upgrade to yet another level (discovered that too late, grrrr). Thus, what do you use?
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John J. Couture
San Diego Miramar College
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As Paul said I use autocad to create boards. Then I have to get the DXF file converted to gerber for the PCB houses. I tried the express pcb software, but didn't care for it. But I guess I should take the time to learn it as they do seem to have the cheapest prices.
Bean.
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"SX-Video·Module" Now available from Parallax for only $28.95
http://www.parallax.com/detail.asp?product_id=30012
Product web site: www.sxvm.com
Available now... SX-Video OSD module $59.95 www.sxvm.com
"I'm a man, but I can change, if I have to, I guess"
Red Green
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Ryan
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Ryan Clarke
Parallax Tech Support
RClarke@Parallax.com
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Post Edited (Paul Baker) : 10/3/2005 7:22:05 PM GMT
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Chris Savage
Parallax Tech Support
csavage@parallax.com
www.sparkfun.com
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Chris Savage
Parallax Tech Support
csavage@parallax.com
I just looked on the website and I didn't see anything about the PCB service being down.
Thanks, PeterM
The PCB service is now frozen. No, not canceled, just frozen. We are launching a new site in the next 3 weeks. If you have an outstanding order, please email protopcb@sparkfun.com to find out the status. We will be happy to service all open orders, but no new ones can be placed until the new website is ready.
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You and Chris are right. I went back again and read all the way to the bottom before I saw the little notice about this. You'd think that the folks at SparkFun would put something this important at the top of the page in big letters of a different color instead of at the bottom in the same color/size text as the rest of the page.
Thanks, PeterM
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