Frets and strings
Control and indications
Algorithm of note detection
All what is needed for MIDI-OUT implementation is already present: ground, +5 V and onboard asynchronous transmitter. Data transfer rate of 31,250 bps is easily achievable. Photon-coupled pair is required by MIDI standard at MIDI-IN, so it is not required in Tryndelka.
MIDI-OUT of Tryndelka is laughable simple. It is shown at the right. (inlets of female DIN-5 are looking to us). Signal is transmitted by two pins, 4 and 5. Pin 2 (ground) is to be connected with cable shield which is not used for signal transmission. "220" means 220 Ohms, not 220 Volts as someone could consider.
In order to connect Tryndelka to PC game port, standard MIDI-to-PC cable should be used with PCP implemented on PC side.