I need to built a device which can detect the frequency coming to it. I shall make it more clearer, ie the remote controlled device i need to built should have a global transmitter, ie i should be able to assign any transmitter for my device. I may even use my TV remote. So for this thing first i need to detect the signal and save it, now whenever the same frequency is found the ckt is activated. So i need to know how am i going to identify that signal.(i know the programing of mc's). Hope the idea is clear. plz help