I'm Conor Patrick. Former {FTC OTRI, JHUAPL} intern. I support open source development. I do research for Secure Embedded Systems at Virginia Tech. You can follow me on Twitter.

My experience with DirtyPCBS.com

13 March 2016

Dirty Cheap Dirty Boards

If you want to order custom made PCB’s for a small price, Dirty PCB’s is probably your cheapest option. This used to just be a service that was internal to Dangerous Prototypes to make cheap boards for their own projects. Now it’s public and they make dirty cheap boards for anyone.

To get an idea, you can buy ~10 boards that are 5x5 cm for $14 (free shipping). You can get more boards, larger sizes, and more layers as well for relatively cheap prices.

Here I’ll share my experience with Dirty PCB’s and photos of a U2F 2FA token I’ve been working on. I ordered the same boards from Seeed Studio as well to compare.

The revisions

This is my first PCB so the first one is pretty dirty by design and not just because of Dirty PCB’s. The next revision is a better layout.

Revision 1 from Dirty PCB’s

R1 Dirty PCB's front

high resolution

R1 Dirty PCB's back

high resolution

Revision 1 from Seeed Studio

R1 Dirty PCB's front

high resolution

R1 Dirty PCB's back

high resolution

You can see that the layout is pretty poor. None of the traces really make 45 degree angles or care about what angle they cross over each other between layers.

Also there is no ground plane. I don’t really need one but decided to add one later.

There isn’t too much of a difference in quality between the two boards. But you can still see why Dirty PCB’s is cheap:

Look at both board pictures in new tabs and you can see these differences in quality for yourself.

At the time Seeed was a little more expensive ($10 for 10 boards + $10 shipping) and charged more for 2mm thick boards which is necessary for me because they fit best in a USB socket. Now it seems their pricing is similar to Dirty PCB’s.

After revising my layout design, I made two more orders from Dirty PCB’s.

Revision 2 Dirty PCB’s

R2 back

high resolution

R2 back

high resolution

I’m not sure what happened to the silkscreen on this one. It seems any traces or ground plane overlapped the silkscreen. I suspect it was an issue at the board house since the next revision, (which is really the same layout, just a different color) did not suffer this problem.

Revision 3 Dirty PCB’s

R3 back

high resolution

R3 back

high resolution

Where to get PCB’s

Overall, small PCBs are pretty cheap. I think Seeed will offer slightly higher quality for a similar price. Dirty PCB’s will charge less for other options like color and stencils and will be quicker out of the board house.

If you PCB design isn’t crazy on tolerances you can’t go wrong with either one.

** Update

Based on replies I’ve gotten, here are some other places to check out for maxing out cheapness and quality:

Check out PCBshopper.com to query the price of most fabs for a given board.