I was taking apart a Grinnel Bros. player piano and I found that
someone had equipped it with a very sloppy electrical system created
sometime during the 1960s.  After I stopped choking from the sight of the
dust / damage, I remembered that people are always talking about
converting rolls to MIDI.

I suppose all you're all after is an electric signal every time a
key goes down right?  This piano had an enclosed system where every time
a key went down, either by hand or automatically played, a corresponding
light would illuminate.  The system was very well done.  I figured it
could have great midi application.  The system was installed on an
upright, where the keyboard cover (fall board I think it's called) was
previously.

For further info, like drawings, e-mail me.

Damon Atchison
Damon66@juno.com