I have designed two PCBs for the MSQEQ7 based audio spectrum analyzer I described in my previous post. See it in action here:
The boards are stacked on top of each other. The bottom one contains the analyzer, timer, and LED driver. The top board contains the LED bar graph displays. The boards are 80x49mm in size in order to fit in a DP8049 Sick of Beige case from dangerousprototypes.com.
Design files (eagle), schematic, etc. on github