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Most ribbon controllers are linear, but the one on the Otamatone behaves like a guitar or a cheap theremin, with higher notes closer together. Can it be made linear?

Mark Green
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  • Hi Mark. Can you clarify what you are asking. You have 2 questions here. – Doktor Mayhem Apr 24 '16 at 16:29
  • Ribbon controllers are basically unrolled potentiometers and, as far as I know, a "Linear Pot" can be converted to a logarithmic one by adding a resistor. Presumably the opposite can also be achieved. – Yorik Apr 26 '16 at 19:02

2 Answers2

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To quote Wikipedia,

The ribbon controller is deliberately delinearized to resemble a guitar, so there is a shorter distance between higher notes than between lower ones. - https://en.wikipedia.org/wiki/Otamatone

Basically, they're doing it on purpose because it's how most intonation-based instruments behave. You'll notice that people who play string instruments may be better at playing the, uh, whatever the Otamatone is. I don't really want to call it an instrument, but in light of evidence, I must say that it is fairly capable. ;-)

General Nuisance
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  • Thank you for the reference, however, I added that to Wikipedia based on information elsewhere. – Mark Green Aug 15 '16 at 19:54
  • Aha! (That's fairly awkward...) Would it be too much to ask for you to post the original source just for reference? After all, that's the point of this site. – General Nuisance Aug 16 '16 at 02:37
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Ok, I think I figured this out. It's not deliberately made like a guitar: it's the same principle as a guitar.

To go down by one octave, the frequency must be halved. On a guitar, to halve the frequency, the length of the vibrating string must double. Since it takes more extra length to double a longer length than a shorter one, the lower notes are further apart.

On the Otamatone, instead of strings there's soft potentiometer (which a teardown video confirmed is a sheet of Velostat with rods to hold it straight) and it works the same way. The lower the note the Otamatone plays, the higher the resistance of the soft pot must be. To play an octave lower, the frequency must halve, so the resistance must double, and your finger must move twice the distance than the previous octave.

It's interesting to follow up and ask if the otamatone could be modded to linearise it.

Mark Green
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