I'll try to address the comments on here, so ask any questions you have!
My approach is a tad different though. My approach works by using the microphone. And I have the code to extract notes from a microphone via a FFT. Allowing for typing with say a guitar.
Extracting single notes works quite well. I haven't gotten around to test chords just yet, but I think I have the fundamentals there.
I'm a bit short on musical knowledge and instruments so so far I've only tested it with my voice (ugh), synthesized sounds and partially filled water bottles.
Also I have a suggestion for a graphical interface that would make the learning curve easier and making it language/alphabet independent.
Please reply to this comment if you are interested in integrating this.
In the long run as I wrote I am aiming to support chords so that'll be necessery.
Would AMDF make the response time quicker?
For what purpose are you doing pitch detection?
RE: integration with what I did - I'm hoping to release the source code one day, then you'd most likely be free to use that code however you want (I'll probably MIT-license it). But as for my involvement, I'd like to be done with this project.
Slight tangent--I've often wondered if the principles behind audio keyloggers, where you record typing sounds and try to reconstruct what was typed, could be used to make a wireless computer keyboard that never needs batteries. Seems like you're attacking an inverted version of that problem.
Interesting stuff, thanks!
Kudos!
Which can be seen in action here: https://www.youtube.com/watch?v=HrUNrb3ihl0
And no, no April Fools here ;-)
Q: Can you play a real song so that we can see what it types out?
A: This isn't as satisfying as you may think since the entire typing range is only about two octaves, and most songs exceed that range, so nothing actually gets typed when you play those notes. Anyway, here's Wonderwall: Iuiuigaezobzgbxgebiuiuigaezobzgbegz
(that's actually the right hand of Für Elise)
There are many things that I would like to say to you, but I don't know how.
As for making something like this harmonically pleasing, it's been touched on here in other threads, but I think the whole project would require a redesign. If you were still aiming for a one-to-one mapping of piano keys to letters, then I think you would end up sacrificing both learning speed and typing speed.