Build a working compact circuit board with bluetooth

I have built a prototype however it is big and cumbersome. I would like to have a printed circuit board with a back up or redundant system. It needs to be a finished product in an enclosed metal or plastic box. The box would need a fire burn rating.

As this is going into an aircraft all components would need to have some sort of burn rating. I really if we can have this in a small self contained housing. The one I built was a 3 wire unit however I think a 4 or 6 wire may be easier to work with.