Greg,

What about mounting eight small mirrors; one on each face of an
octagonal piece of wood rotated by a small motor. One face is
perpendicular to the floor and each successive face is tilted
upwards slightly.  An optical sensor establishes the position of
each mirrored face.

Then as the block spins you need only modulate the laser on and
off.  As face number one rotates into view, you display the
bottom row of 'pixels'.  Then as the second face comes into view
you send the second row.  Because the second mirror is tilted
upwards a bit, these 'dots' form the second row.  Etcetera.

I don't recall where, but I've seen a few articles and/or web
pages on this approach.

Andrew







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---- On    , Greg Miller (gmiller@GREGMILLER.NET) wrote:

>         I thought it'd be fun to use a mirror to scan a laser
across a
> wall for a display.  I've had several ideas for how to make
the mirror
> scan the beam across and up and down, but they all seem a bit
beyond
> my mechanical abilities.  The latest idea I've come up with is
to put
> four permanent magnets on the back of a mirror, and a coil
behind each
> magnet to push/pull the mirror which is mounted on a pivot in
the
> center.  Will that actually work?  Is there an easier way?
>
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