What does the invisible man play? An invisible instrument

To date, we've been calling our instrument a "shadow harp".
While this is accurate - the instrument detects the presence of shadows in order to play notes - we've been undecided about the name for a while. Really, because Peter DeSimone has already created an instrument he calls a shadow harp (albeit one that was abandoned and replaced with his "pocket harp") and although this instrument was inspired by his, it really is a different project (more in-line with his original pin-hole light harp than his final shadow harp solution).

After a bit of debate and a few beers (ok, a few cups of tea) we decided to call our version the "invisible instrument". It's a specific enough name to convey what the instrument does (it's an instrument but the playing surface is invisible) but vague enough to allow for modifications and changes to the design and behaviour in future revisions!

So from now on, any references to a "shadow harp" are purely accidental - we mean, of course, "the invisible instrument".