And we decided to do things our way...

I know it's been a while since my last post but I assure you my work has by no means slowed down. We have now designed a fully functioning dip compatible arduino with USB that that's still packing the DIP 168 (Allowing you to throw the 328 in if you're so inclined). The final layout is found below:

So lets talk about why this thing is the way it is and what functionality we were interested in maintaining from the original Arduino and Really Bare Bones Boards. The latter of which you can find at ModernDevice.com

First of all, our biggest issue with the RBBB as cool as they are was the lack of USB. We're space limited, and cash limited so as many systems as are going to be driven by the Arduinos on the SeaWolf III having to purchase (and find room for) a bunch of TTL to USB cables wasn't high on our list of things to do. We were more interested in dealing with the headache of soldering the FTDI chip directly on board. And yeah... we chose SMD (surface mount device) soldering over running cables as the easy way out.. go figure.

Secondly we wanted to keep the DIP compatibility found in the RBBB, the pin headers are spaced 3/4 of an inch apart with power, digital IO and analog IO pins pinned out. I realize that this is a kind of proprietary pin out but we are intending to design our own daughterboards for different systems and in large, not doing anything thatthere are sheilds readily available for.

Even with the addition of the FDTI TTL-USB chip we wanted to keep the form factor small. Therefor we opted for a 2 layer board with mostly SMD parts (note the amount of space the non SMD diodes take up over the SMD LED). The two layers allowed for drastic reduction of size, and can (or not depending on just how crazy small you're trying to make things) make traces a whole lot easier to run.

Like is found on the Ardunio, we ran a big 'ole grounded heatsink under our voltage regulator. (basically just drew a poly in and filled it with copper under the v-reg). This reduces the chances of one attempting to burn holes in their hand when dealing with boards that have been running flat out in a pelican box all day.

While we're on the subject of V-regs, we're using a very pretty little V-reg manufactured by Analog Devices. We opted to use the ADP3339 due to it's extremely clean power signal and attempts to stop things like reverse bias and overheating.

These are about our biggest changes to the Arduino board, hope you can find some use for it if you feel so inclined. Coming up shortly I'm going to cover a few things I learned in creating this board for future PCB designers. This is my first board so it was in large a learning experience.

Found below is the final Schematic uploaded as a PDF. The Eagle files are attached as a .zip.

SeaDuino Schematic.pdf

SeaDuino 1.2.zip