I have a DIY computer which looks like a 7" tablet, only thicker. The case is plastic, and the whole device is about as thick as a laptop. There are no scary wires popping out and no ticking noises, and there's no problem to turn it on upon request. Opening the case would be a problem though, since it requires a screwdriver and the components (main board, LCD, WIFI antenna, battery) are interconnected by rather fragile cables. All components used to build it are FCC certified, but not the computer as a whole, obviously; and FCC labels cannot be seen without taking it apart. It is powered by a Li-Ion battery of 11'200 mAh and 42 Wh.
Pictures are (c) Dmitry Grigoryev, distributed under CC BY
I use it (among other things) for games and movies, and would like to bring it on my trips. Do you think I may face any issues during security checks, especially considering the latest events? I live in France, so answers about European regulations and practices would be the most relevant. However, I do occasionally have international trips (about 3 per year), and any advice about other countries is welcome as well.
PS: the closest information I've found is this question, but it doesn't really help in my case. Coming to the airport one hour in advance and having the luggage checked by the police is definitively too much trouble, I'd rather bring a book on a flight instead.