Googling... Hey that's a very pretty microphone.

There's a "instructables" page which describes the conversion process but don't follow that one. It's terrible because it's just gutting the mic and putting a cheap plastic computer mic in place of the original D104 innards. I mean, that would work, but then it's not a D104 any more, just a shell with a lower-quality piezo mic inside.

I'd rather figure out how to adapt a D104 to a USB audio interface. I don't see anything on that topic yet, but it seems these mics are popular and I'll bet someone's done it somewhere.