The "How To" of Stepper Motor Music - Part 1: Note Frequencies and Accuracy

[usernameunave0]

Lastly, and sorry for the flood, but I easily noticed the difference between 880/890, and personally I find even a 10 cent difference noticeable. It's especially grating to me with synthesized music where you can have extremely fine-tuned control over the exact frequency you play each tone at. I get that both your motor and controller dictate the exact frequencies you're capable of playing, but why not take that into account and scale up until you reach high enough that it's less of an impact?

[cmhiekses]

@usernameunave0 Yes, the difference between 880 Hz and 890 Hz is noticeable and bothersome to everyone. BUT, if one of those two notes came at you surrounded by others in the context of the mario video, you probably wouldn't have noticed (for several reasons, many of which have nothing to do with your ear).

Your question is an intelligent one and is serving as inspiration to make another video (maybe even today). The idea you've got is the right one but there are some practical problems. :)

[usernameunave0]

@cmhiekses Interesting, I can't wait to see it when you're finished. I assume, at least in the context of using floppy drives, that one might be the fact that when you move the motor forward or back a step, you're actually moving the read/write head, which can only move so far before needing to reverse direction like a violin's bow? I have seen videos of people "playing" 3.5" drives with the tops removed, and there seems to be a noticeable change in sound between one direction and another.

[usernameunave0]

Also, holy crap. Although it's been ages since I seriously played anything, I like to tinker with the piano roll in FL Studio to make little mini-arrangements and stuff, and when you mentioned A4 there, I found myself instinctively whistling it, then you played that 440 Hz tune, and I was almost spot-on. Guess some things you never un-learn huh?

[cmhiekses]

@usernameunave0 Pitch identification is something you can actively work on and practice. If there were any pitch you'd know by heart, I'd expect it to be A4 (people with a band background can usually summon up an F or a Bb without too much difficulty as well).

[usernameunave0]

Heh, I have a pitifully short (~8 years playing various instruments from 6y/o) and for a second there when you mentioned "knowing the difference between an F# and a G" I thought you were pulling some kind of fast one like "the difference between E# and F", and then had to spend a few minutes seeing if there was some kind of high-level music theory that actually differentiated those.

[cmhiekses]

@usernameunave0 There actually is a difference between an E# and an F and, yes, it is a high-level music theory explanation for a different time.  I do encourage you to go look it up on your own, though. The mathematics of harmony are really fascinating.

[hattentojou]

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[acealexander702]

You look like my band teacher :3

[Jakub1POLSKAnew]

Waiting for the next part :>

[MusicGaming1]

CLARINET HERO!

[jcayer2]

Excellent tutorial !!!

Thanks !!!

[rbertoche]

I'll start with something that will probably be ugly with PC-Speakers, then i'll play with an CNC set with 5 steppers directly plugged on a parallel port.

[rbertoche]

Hey, i'm planning on doing something alike. Can you publish the code with the information about how long you wait for each note to end, and the frequency or the period of each note?

It looks like you've done an excellent job on that, much better than all those engineers that knows a lot about CNCs and how to get good torque with steppers but nothing about music and polyphony.

[denimslugs]

sod the maths.....just look at this chart i found. w w w phy mtu edu / ~ suits / notefreqs (take out the spaces)

[KoMaHu3aM]

dude u rock ...

[com3t]

AAWWWWW you put part one up but not part two!?!?!?!?!?

[jimday666]

will be more parts to this tutorial?

[irontiger444]

Wow. Quite the informative video.  Very interesting!

[tsport100]

Classic Engineer egg head, thinks all life is a math equation.

Give us a link to a freq chart of the keyboard and forget the formula.

[Zombunist]

Great vid and good luck on your PhD!

[danz409]

iv never noticed how much math there was in music... thanks for pointing this out ^^;

[Bp1033]

This really helps me with what I'm doing which is kinda sorta (not really) close to stepper music. I'm making pc beeper music in QBasic but the hard way. No Play command for me! I was digging all over the net for this info. Thank you!

[danz409]

this video is bufferfucked, aka. even with a 10 meg connection it doesn't load but 20 seconds of video in 10 min. might want to re upload or contact you tube on this one

[darky10121987]

o.o i almsot passed out brain fry

[AlonTavor]

6 months have passed....

Where is the next video? :(

[cmhiekses]

Sorry! Working on my PhD has sort of taken over my free time. I'll try to get a new video up soon.

[konayasai]

@cmhiekses 16 months have passed. No pressure :) but how's part 2 coming along?

[cmhiekses]

@konayasai Expect another video in February (after I've finished my PhD).

[djguyndai]

*waits on next video*

[explodingPSYCH]

how well can you do portamento and vibrato with these motors? i'm curious about the physical limitations of using motors like this, but i'm not familiar with them. thanks!

[cmhiekses]

The biggest limitation on these motors is acceleration. Without the right kind of hardware to provide current the motors properly, they will lock up if you try to jump them from zero up to some very high rpm.

Portamento and vibrato would be difficult. The only real control you have over the motors is the timing of the steps. In general, there is no way to control dynamics. These motors are essentially frequency actuators.

[barnumeffect5]

440 MHz is what the ISO adopted as a standard. It was different during the baroque era. they used a meantone temperament, which was the basis for the picardy 3rd. because due to the temperament V- I cadance sounded more in tune than a V-i cadance.

This is very good and rare info. the 12th root of 2 is describing just intonation.

if you are majoring in music i wanna know what ur major is. I'm an acoustican. i wanna study this cause it makes me happy. and what i'm studying now barely does that.

[cmhiekses]

@barnumeffect5 I am not majoring in music. I am working on my PhD in Aerospace Engineering. I am a rocket scientist.

[XdontUworryX]

lol owned

[invisiblegecko]

then you have the right to say "duh...its not rocket science" lol

[stolevole]

@barnumeffect5 440MHz is standard for birds and dogs, humans are ok with 440Hz :)

[ueberRegenbogen]

Wouldn't a certain amount of timbre/amplitude control be possible by stepping and quickly counter stepping (somewhat like the quarter tracking of floppy drives that was used in some of the copy protection schemes of the early '80s, and, for that matter, timbre control of the Apple II's flip-flop driven speaker)?

[PokeParadox]

Thanks for this video... while I have no intention of ever making music with stepper motors, I did want to code my own little crude sound library for fun! This explanation clarifies a lot of the problems I would have had to work out, so again thank you!

[LinkinParkGameFan]

Interesting shit, I'd like to know more about the calculations myself.

[bgriggstwcny]

Excellent video and explanation of how you are generating music with steppers. I have been looking for some information about this topic for months. Thank you.

[homogeneousally]

Way awesome explaination! I love the Clarinet Hero shirt too! I want one!

[counterfeitcoin]

wow, a little physics, music theory, and algebra all rolled up into one; thanks mr. stepper motor man.

[clubpenguin1help]

Its much clearer now, I finally understand how it works...

[linuxlove4004]

i'm no musician but i have a good sense of pitch. i also need to pay more attention to my math wotk :o

[cmhiekses]

A few of the strange sounding notes are due to the motors buzzing on the table at certain frequencies. What I really need is a sheet of aluminum that I can screw the brackets into.

[pdmillar]

I thought the intonation sounded kind of funny on the Mario video, but that added to the charm for me. Kind of like the low frequency resolution of Atari 400/800 music. Do you use a lookup table for the note periods?

[cmhiekses]

Yes. On that particular video I was running a timer interrupt every 40 microseconds and then deciding whether or not it was time to step each motor. This means that my note period resolution was only 40 microseconds.

If you speed up the interrupt, your resolution improves, but the interrupt starts to take up too much time in general and the timing suffers. The atmega328 on the arduino starts to have trouble when I get close to 25 microseconds on the timer interrupt.