Midi decoder boards

What is a midi decoder board used for? 

Forming the interface between your computer (or player as MIDILECTOR Midi) and your mechanical musical instrument (organ, piano, accordion ..). You plug a MIDI cable / USB from the computer to the MIDI board input socket. Connect an electromagnet to each board output. These solenoids open valves or pull on levers to produce notes on the instrument. The board’s job is to switch on or off the electromagnet corresponding to the note read in the MIDI file on the computer or SD player.
You can also drive DC lights, within the board’s current limits.  220 volt lights can be driven by the use of relays.

There are 12, 16, 32 or 64-output Midi decoder boards with 500mA up to 2000mA current per output.