Trying to figure out some sort of method in which it would be possible to detect nearby phone numbers e.g. within a private premises.
My only lead so far is to build a mini mobile base station that would let phones connect to it - even then my theory for this has many holes and blanks.
The above may be completely off or possibly I may be on to something, either way if someone could give me a rough idea of what direction to take it in that would be much appreciated - I do not require any kind of code as I would much rather figure it out myself via a finger pointed in the right direction.
Even if you do not have any solid answers but some tips that could possibly help me piece this together, that'd be great.