Kindle 3 serial plug designs
I thought i might as well post the mechanical design I use for my Kindle serial plug since the other plug designs i have seen here do not contain the notch you need to insure a good connection with the 2 serial pins.
You can see why you need the notch when you take apart the socket the K3 has. I wish i had done that at the start because i had lots of headscrating moments why the damn plug would work one moment and not the next.
It also led me to discard a perfectly good sparkfun level converter as "broken".
Right now i use a Bus Pirate to interface the kindle.
To etch you need the following:
Etching solution (natriumpersulafte)
a single sided copper clad board (a really small piece of that board really)
a page of *inkjet* glossy photo paper
an old toothbrush
print the .brd file with EAGLE in Black+White to the paper and iron it to the copper side of the board. The printout should look like the png I included.
use some warm running water and the toothbrush to remove the paper.
etch the board in the etching solution and then cut the board down like the one in the attached photo. Your board will also be probably too thick. you need to file it down by 1/3 if you have standard thickness board.
after that attach a suitable 1.8v serial adapter or level converter and enjoy.
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