AVR-Chat

Jim Wagner said:
>
> Javier -
>
> Doing what you suggest is difficult. It is not difficult to
> measure signal strength (of many signals, including radio).
> The problem is that, at almost all frequencies (from audio
> to light) there are reflections that result in constructive
> or destructive interferance. Light tends to be less
> susceptable because of the short wavelength. You could use
> a light source (LED) and pulse it. The pulse signature
> could be used to separate the desired signal from the
> background (ambient). But, sensing the signal over a wide
> field of view isn't so easy.
>
> Just an idea. Maybe others will have more suggestions.

I'm not sure that I remember the original question, but:

At work, we use quadrant detectors for laser tracking.

Imagine a detector array that looks like this:


      AB
      CD

Where A, B, C, and D are separate (but usually on the same
substrate) light sensors.

Up and down detection is given by:     (A+B) - (C+D)
Left and right detection is given by:  (A+C) - (B+D)

With some decent detectors and optics, you can get a
quasi-proportional output to steer your gimbal mechanism.

Equal output on each of the four sensors is achieved when
you are dead on target.

A fellow on eBay with an id of: thane*grooms  has occasionally
had some PIN diode quadrant detector arrays for sale with
integrated optics.

Mike