I need help in wireless Distance proportional Signal System

What i need is clearly explained in this diagram

Now, What i need is two circuits A and B

As show in the diagram B must be a emitter or watever
A must get the signals from B and must display (or output a value to Micro Processor) which is proportional to the distance between A and B.
So when i move the circuit B .. the value in A must change accordingly

I need your suggestions and help
I am a complete Noob in this, I am from Computers department

Hoping for help
Thanks


( Sorry , If I posted in wrong forum )

 

You didn't say how far "x" might be, and what interference there might be between A and B. For short and unobscured distances, you could just get one of those ultrasonic range finders or laser "tape measure".

 

15 Feet range
No Obstacles
Thank You

 

waiting for someone to help :\

 

What's wrong with the suggestions you were already given?