I wanted a compact solution to the breadboarded rat's nest that currently controls my rig (sorry, it was intentionally left out of the pictures in other threads). After seeing that Sparkfun's BatchPCB
service was pretty cheap, I thought I'd try my hand at PCB design. I used the freeware version of Eagle and a template from Lady Ada
. I ordered two Arduino shields and two accelerometer breakout boards (I got some sample accelerometer chips and want to see how they work). The designs were submitted on New Year's Day, and 3 weeks later, I received four of each board. BatchPCB sends extras if they are forced to run extra panels due to flaws. Sweet!
The good news is that the shields fit perfectly, and they all test good for continuity. The bad news is that my circuit design was slightly flawed. It's nothing that can't be overcome with a few solder bridges (visible on pins 1 and 2 of the SO-8 ICs) and a little creativity. My biggest mistake was isolating some of the ground plane pour from an actual connection to ground. I also wish that I'd provided some headers for PWM output. I've likely violated some design rules since I have no formal training in PCB design. Silly mistakes notwithstanding, I'm very happy with the results. I can read four separate thermocouples using SPI, and I have simple connections for all of the analog pins and a few digital pins.
Here's a pic of the results. I kept a few prototyping features on the board just in case I want to change the configuration later. A MAX6675 chip is missing - one of them tested bad.