Ball Bearing DRO

The ball bearing DRO idea has been on my mind ( although I think a guy
might have to buy a LOT of bearings to get enough the same size ).

I think a sensor could be built using the same sort of idea that metal
detectors use. A small coil is part of an oscillator. The oscillation
frequency changes as a result of proximity to the iron.

Nice side benefit is that no A2D is required - simply a counter. "Counts
per ball" would be determind by uP counter speed/oscillation frequency
( I think ). One of those nice fast scenix chips could be used to
provide clock/dir outputs.

The two problems with this otherwise attractive idea, it seems, would be
oscillator drift as a result of temperature and keeping the two oscillators
at PRECISELY the same frequency. Both are sources of error tha would QUICKLY
throw the count off.

Now, if the balls were magnetized, a pair of hall effect devices could be
used. Here, an A2D WOULD be required.

Just a thought.

Alan

--

Alan Rothenbush | The Spartans do not ask the number of the
Academic Computing Services | enemy, only where they are.
Simon Fraser University |
Burnaby, B.C., Canada | Agix of Sparta