Anyone have experience with analog Hall Sensors?

[n8cutler]

Good to see you back on here!

I've done very little with Hall Effect sensors.  But, I have built two of these: http://zeltom.com/products/magneticlevitation
I can tell you that the Hall Effect sensor will pick up a small neodymium magnets several inches away, and these sensors are well under $10.  The resolution is good enough to be able to adjust the electromagnet to keep the magnet suspended in air.

By "rotation of the magnets", you are describing the magnets rotating around what they are mounted on, correct?  In other words the axes of rotation is external to the magnet (like Earth orbiting around the Sun), not a magnet spinning around an axis through the magnet (like Earth spinning on it's axis)?  If you have a quick sketch, that may help.  Depending on how your objects are rotating, it may require two sensors per on if you want to detect rotation beyond 180 degrees.

With the Hall Effect sensors I am using, I believe there is a way to configure them to do what you desire.  The sensitivity and resolution would support it, provided the proximity, etc. were designed properly.  I'll look around to see if I have any extras around.  I know I originally bought more than two.