Arduino midi controller (but special)

Using Arduino Audio
1

recently i looked into getting a keyboard midi controller. we already have a piano but a piano doesnt have ports, so, i looked into getting a keyboard. however, keyboards are expensive, and i would prefer NOT to spend hundreds - potentially thousands - of dollars on somthing that would just be a little convenience thing for when i write songs. so, now i had the idea to take a microphone, run the frequencies through a couple calculations and output a midi or usb signal compatible with musescore and maybe garageband. i would have some switches on top for whether to output notation or audio or none at all, and maybe a couple potentiometers for tune and stuff like that. im not very experienced with audio though, and have no idea how to give a usb signal, never mind one thats compatible with other programs.

as you can probably tell by my description, im quite inexperianced in this field. i would like advice on which calculations to use in order to round to a perfect frequency, how to give a usb signal (thats compatible with other programs), and maybe some part suggestions. thanks!

2

You've chosen one of the most difficult problems in audio. Even programs costing loads of money with the full resources of a top-end PC to work on only get it right about 85% of the time. Any real music note contains lots of different frequencies and just identifying them all then working out which one is supposed to be the "note" takes a lot more than "a couple calculations".

If you're talking about an electronic piano then maybe there is a way to get inside and work out which note is being pressed then go from there. That is done fairly often.

Steve

3

I think this would require months of research and development, maybe years. With the greatest of respect, I think it's a non-starter.

I don't think keyboards are expensive, so long as you buy secondhand. Look at this one, for £50 (UK pounds):

This is identical to mine, which I use for MIDI development work.

4

If you want an insight into the problems of pitch detection, this paper might give a hint of the real world performance possible: https://web.ece.ucsb.edu/Faculty/Rabiner/ece259/Reprints/107_comparative%20pitch%20detectors.pdf

Its an old paper, but the cutting edge hardware back then is a rough match to cheap microcontrollers of today in performance :slight_smile:

Slightly more modern take: http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.58.834&rep=rep1&type=pdf

6

Each piano key does not produce a single note. Each one produces a complex pattern of many notes. When two keys are played at once, each produces it's own pattern of notes and a third pattern of notes is formed by the combination of the first two patterns. If 3 keys are played at once, 3 patterns of notes are produced and 3 more patterns are formed from each combination of 2 of the 3 notes. If 4 keys are played at once....

That couple of calculations probably turns out to be a couple of million calculations, and you need a university degree in maths to understand them.

It would indeed be "special"!

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