He reckons it cost him about $5 to build each of his cheap USB MIDI adapters which receive notes and pedal data from the keyboard’s MIDI OUT and transmit them to a computer Besides the Pro ...

but their Casio keyboard only had MIDI over USB available. To get around this, [adriangin] set out to add a standard MIDI Out port to the Casio PX410R. If you want to be a hardware hacker ...