i'm working on an art project and i need to design a circuit that will change the volume of an audio signal relative to the distance between 2 points in space.
...4 small portable transmitters (probably RF) send out signals to recievers which they are tuned to...the closer the transmitter gets to its reciever, the louder the corresponding audio signal.
i would like this to be all analogue.
can anyone point me in the right direction as far as what electronic concepts would be involved? where i can find circuit designs that achieve at least part of this effect?
any help would be greatly appreciated,