I have MIDI keyboard (MIDI interface, not MIDI through USB) and want to make it to control 12 colored lights (LEDs probably as incandescent bulbs may not be fast enough to follow the music), one per musical halftone. The LED should light when the key is pressed down and go off when the key is released up.
One of the approach would be connecting the musical keyboard to PC through adapter, write some software and add USB to relays controller to control the lights. This adds the complexity of the whole personal computer (ok, maybe laptop) involved. I would strongly prefer to have the independent device instead.
Is it possible to build such a controller without building and using a PC?