I've made an Ethernet shield compatible with the official one on
through-hole components. Works well just like the original E.shield.
Schematics are similar to the official one, but I have 47nf cap
on RST line to avoid the reset problem with W5100.
I've started this project in January 2011 but due to long delays with
PCB manufacturing and other business it reached the real product stage
just now. This was big fun, I had to study datasheets and prior
designs (like Wiznet's reference schematics, Ethernet shields from
Arduino and Freetronics) and learn about PCB routing.
Apart from PCB, total parts cost is about $12 ($6-7 for the IC, $2 for
the pimped RJ-45, the rest is about $3). PCB cost is about $7-10 on
small runs. So total cost is about $20.
Once you solder the 0.4mm-spaced LQFP chip ] (which was a minor pain
even with my burnt to crisp $5 noname iron), the rest of the board is very
easy to assemble even for novice hackers without pro soldering
tools/skills.
I used gEDA suite to produce board schematics and layout, which
required little of custom symbols to be made. I've attached the
schematics image.
A number of problems became evident as soon as I completed my first
assembly.
Things which would make the board better include lower crystal,
regulator leads leaned, bigger holes for ferrite beads and LED silk marks.
There's an updated design which adds SEN=!SCS invertor and merges
grounds, layout has been redone from scratch; I haven't manufactured
any of these.