-- forwarded message, please reply to sender and MMD --

I have made a device for my 8 and 10 year old daughters to enable them
to play our piano without any music lessons.  It is a wooden rack that
holds a roll of paper about 36 inches wide.  The wooden rack sits on the
music rack and is removable.  As part of the rack, an idler roller is
placed just above the keys.  The paper roll goes around the idler roller
and is wound up on a take-up spool with a variable-speed motor attached.
I made a marks with a magic marker on the paper.  When a mark reached
the keys, you pressed the key down.  When the mark stopped, the key is
released.

My daughters and their friends enjoyed the music machine, but the paper
would not track.  It would move over to one side and split the paper.  A
friend suggested making a crown on the take-up roller but this didn't
help.  I looked at the tracking mechanism on a player piano and saw the
tracking holes at each end of the row of player holes and the little
bellows which moved the roll to the right or left.  I didn't want
something that elaborate.  I thought about a microswitch at each side of
the roll which would activate an electric motor, but I wonder if there
isn't an easier way?

I found some commercial devices that make the keys of a keyboard light
up when it is time to press the keys.  The problem is that there is no
warning where you need to press the next key.  My device has the supply
roll about 18 inches above the keys, so you have that much look-ahead
time to get ready for the next note to press.

Sincerely,
Hal Waters