"Eric Meurville" wrote in message
...
It would be great if the position sensor output could toggle every
360/2^N°, with e.g. N=6 (that means every 5.625°). More would be better.

If the rotor is a two pole magnet, perhaps you could surround the rotor with
say 64 hall effect sensors. Scan and convert the analog value of each sensor
many times a second and "plot" a graph. Do averaging to improve S/N ratio
and curve fitting to look for the maximium and minimium flux positions
(indicating where the north and south poles are).

However I think I would investigate using something else in the rotor -
perhaps a directional antenna/coil that's externally excited? It's usually
better to start with an AC signal rather than a DC signal if you think you
are going to have S/N ratio problems.