[LAU] Wah update

[James Cameron]

On Thu, Aug 20, 2009 at 05:21:10PM -0700, Ken Restivo wrote:
> On Fri, Aug 14, 2009 at 10:19:25PM +0100, Folderol wrote:
> > Double Hmmm
> > Fix it so that the index pulse is at exactly the halfway point in the
> > travel, and it will 'silently' re-calibrate itself every time you pass
> > throgh that point.
> 
> I don't know what an "index pulse" is. If you could point me to some
> good introductory reading material on dealing with encoders, I'd find
> it very interesting indeed.

An index pulse is a unique output of the encoder that can be recognised
by the microcontroller for some purpose.  Usually to recognise a home
position.

The other pulses emitted by the encoder correspond to movement in a
position beyond the index pulse position.

Obviously, you'd need an encoder that has this feature.  There are very
simple encoders that don't have it ... e.g. the X and Y optical encoders
in older "non-optical" ball mice.

-- 
James Cameron
http://quozl.linux.org.au/