For my project, I made a dog/cat/some 4 legged thing up to the viewers interpretation. The emotion that is portrayed is fear.
It starts off on alert, with pulsing orange lights. Once it calms down, the lights turn off. At this point, if it detects any motion it goes crazy until it wears itself out, and the cycle continues.
There were a couple of technical issues that had to be solved, like servos not playing nice with neopixels on the arduino at the same time, but nothing super serious.
video – https://drive.google.com/file/d/0B6bFUuOZ0DHJRjI0amFveDNjUnc/view?usp=sharing
code – https://drive.google.com/file/d/0B6bFUuOZ0DHJeXFSZGVZLTNXa1k/view?usp=sharing