Upvote:2
You will definitely not be allowed to use your custom device on your Easyjet flight. They list what can be used, and specifically say that devices without a "Flight Safe" mode must be switched off.
Upvote:7
There aren't any regulations I know of specifically covering bringing DIY electronics (it would be a weird thing to make a regulation about). I've carried them many times, and only had something inspected once: They swabbed it with an explosive detection swab, waited for the beep, and let me go on my way.
Actually using such a thing on a plane may be different. I'm gonna go waaaay out on a limb and guess that you haven't subjected that thing to EMF testing.