This is an old design of a microtonal keyboard designed in 1850 by Mr.Bosanquet in London.
A Touchboard of this kind could be easily constructed by using a 1V/Octave resistive voltage divider with 1/48 increments. However, due to the resistors tolerances varying wildly, the pitch would 'nt be entirely correct. A better approach - and much more expensive- would be to have one trimpot per key : each key could then be tuned ,according to any harmonic or inharmonic scale , such as in an unquantized 48 steps sequencer.
