About 10 days ago I was traveling and posted an off hand comment asking if anyone had experience getting an arduino through airport security. Today I started reading Mikal Hart's fascinating puzzle box story
http://arduiniana.org/projects/the-reverse-geo-cache-puzzle/
and I see that he took considerably more than the arduino alone to France. He remarks that he disassembled his project to increase his chances.
It still seems like a risky proposition. I'm curious what experiences people have had.
I was traveling with my project once, as long as it's in a neat case and doesn't look like a bomb or anything dangerous, they will let it through.
Another tip would be to make the project easily open-able so that they could see your electronics. If you do that, it'll be proved not to be a bomb or anything against TSA regulations, and you'll be let through.
Keep in mind, BE PREPARED to have it shipped back to house if they do not let it through, that has NEVER happened to me but it's a good idea to expect the worse... (-:
Elijah