S2MIDI is a windows program that attempts to read raw MIDI data coming in on a serial port and send it to an internal MIDI driver.
We wrote it to get MIDI from the Arduino physical computing platform into Windows based music software without the grief of scary unsupported closed source drivers. In theory it can be used for all kinds of things but your mileage will vary.
The Arduino platform can send MIDI data fairly easily via its internal serial port but this approach has two problems. Your computer needs a MIDI port (more hardware to lug around) and you still need to power the Arduino somehow. MIDI adapters don’t generally provide volts. An Arduino with a USB port gets you around both of these problems, but a Windows PC won’t receive MIDI data via a serial port without some scary device drivers. S2MIDI is a little hack that attempts to accomplish this without as much drama. Full Windows C# and Arduino source code are provided.
Warning, this was our first C# project, use at your own risk.