Let's Design and Build a (mostly) Digital Theremin!

"I don't know what you're talking about!"  - tinkeringdude

It's a reference to an old Twilight Zone episode "It's a Good Life": https://www.imdb.com/title/tt0734580/

"Maybe adding some nose resonances, if you found what they are, to make it closer?
I guess the nose part is a part of the normal formants, so only a part of them gets shut off when the mouth closes...?"

Yes, I've already got a nasal formant for the basic, non-humming voice.  For the humming variant adding another higher up seems to make it a bit more realistic.  It's hard to know where to stop with adding minor formants, and the more you add the more they have to be balanced with the others in terms of levels, and even three can be a juggling act to find what you're looking for (which often narrows down from "this specific voice" to "anything realistic sounding").  I wish there were software that could take a voice recording and spit out formant frequencies, levels, and dampings.  PRAAT is sort of OK at the frequencies, but there's a lot of detail left to dial in monte-carlo style.

You've given me some good suggestions (mama and nose pinch), I'll try them via recordings of my own voice today.  Thanks!

D-Lev is D-LIVE!

While I'm coming up to speed on the ins and outs of our shiny web v2.0 world, I stuck a placeholder here: https://d-lev.com/

But where are the sound samples?  Without sound samples this smells like vaporware to me .

Did you end up going the route we were talking about or something else (you don't have to divulge details, just yes or no is fine)?

I have a feeling that we're all going to have plenty of time on our hands to build theremins and polish websites. It was going to be either this or a zombie apocalypse, and right now I'm sort of wishing it was the latter.  At least you can see them coming.

"Did you end up going the route we were talking about or something else (you don't have to divulge details, just yes or no is fine)?"  - pitts8rh

Got some advice to check out Bluehost, which I did, but iPage was a shade cheaper for Domain re-up, and the 3 year deal for $71.64 was hard to beat / resist.  And I didn't get lost on the iPage website while trying to give them my dang money, which I appreciated.  Have to start paying the $18 re-up fee in a year, and the price spikes like an Olympic volleyballer at the end of the 3 year deal, but whattayagonnado.

I looked at Wordpress but couldn't tell from their site what the download was exactly?  (Being on a Linux machine, one must scrutinize these things so as not to waste time downloading Win exe's.)  It's like I missed an entire chapter out of the book or something when it comes to new web tech, so much is assumed.  I'm going to try riding bareback for a while (HTML) and see how far it can take me before I'm tearing my hair out (devil you know).  I'm not anticipating anything interactive or point-of-sale, more of a showcase with some technical background and contact info.

"I have a feeling that we're all going to have plenty of time on our hands to build theremins and polish websites. It was going to be either this or a zombie apocalypse, and right now I'm sort of wishing it was the latter.  At least you can see them coming."

Yes, but I'm not getting anything done for gawking at it. 

Well, I did get a bit of work done on the librarian:

The slots list is now saveable as a *.bnk (bank) file, which is just a list of *.dlp preset file names.  The presets listed in a bank file can be uploaded to the D-Lev slots, starting wherever one wishes.  So you can list a section (or all) of the slots on the D-Lev with STOL, then save the list to a bank file with LTOB, perhaps edit it with a text editor, then upload the presets listed in the bank file to a given section of slots with BTOS.  This mechanism can pump all the presets at once in a new D-Lev, or can pump them in sections.  I want to use F4 to list bank files and software files, but after that I think it will be done enough for a while.

[EDIT] I added *.bnk and *.spi files to the F2 file list - now they can be deleted, copied, renamed, etc.  So no need for a separate F4 listing screen.  Always looking for ways to keep things minimal (a lost art - or even goal - it seems).

"I looked at Wordpress but couldn't tell from their site what the download was exactly?" - Dewster

Hopefully you started at the correct Wordpress page:  https://wordpress.org/support/article/how-to-install-wordpress/

*Note that it is wordpress.org, NOT .com. 

I just noticed that the recommended MySQL version is correct for my server but the PHP version is older (mine is 5.5.22; Wordpress recommends 7.3).  I was just on with support and could have asked them, but if any issues come up you might check into this.

Oscillation Vascillation

With the librarian coding feeling more or less behind me, I'm considering the oscillator again.  Here is the basic topology from before:

And here is a librarian screen to show the user interface knobs:

The 0_OSC and 1_OSC pages control the oscillator parameters.

0_OSC, left:
hmul : osc 0&1 harmonic multiplier (all, odd, etc.)
hmul : osc 2 harmonic multiplier (all, odd, etc.)
vmod : vol axis modulation for xmix
xmix : xmix (crossfade between osc 0&1 and osc2)

0_OSC, right:
sprd : osc 0&1 spread (+/- offset of pitch)
offs : osc 2 offset (* offset of pitch, +/- 1 octave)
pmod : pitch axis modulation for xmix

1_OSC, left:
harm : osc 0&1 harmonic level
vmod : vol axis modulation for osc 0&1 harmonic level
vmod : vol axis modulation for osc 2 harmonic level
harm : osc 2 harmonic level

1_OSC, right:
oct : octave (for all oscillators)
pmod : pitch axis modulation for osc 0&1 harmonic level
pmod : pitch axis modulation for osc 0&1 harmonic level

The thing that's nagging me: I never find myself adjusting the harmonic levels, nor the modulation of them, differently for osc 0&1 and osc 2.  That is, when setting the harmonic & mod levels, I always set them the same for both osc 0&1 and osc 2.  So why not combine these 6 knobs to 3 and use the remaining 3 knobs for something more useful?

Two uses I can think of are:
1. Explicit pmod & vmod control over the oscillator amplitude - right now the oscillator amplitude is always controlled by the volume axis.  For example, I've got explicit pmod & vmod control on the noise generator and pitch preview, so you can control how they mix in/out via the two axes.
2. Fractional pmod & vmod control over hmul - I had this in an earlier incarnation of the oscillator and it was a blast to play with, kind of a ring modulator or sync effect.  Not very "musical" though.  And which oscillator(s) should it be applied to?

Boaty McBoatface

Got the Ender-3 3D printer yesterday, put it together, adjusted as many things as I could, fired it up, ran a gcode program that helped me level the bed, then I went to bed.  Roger recommended I download Cura, so I did that today.  It's an Appimage in Linux, so it's just one executable file (love those).  I downloaded the 3dbenchy boat file, sliced it in Cura, and exported it to a gcode file - this was literally like 5 totally painless brain-in-neutral mouse clicks, unbelievably straightforward.  Figured I had just enough plastic to print it (a little bit comes in the Ender-3 box, and Cura said it would take 4 meters).  Two hours later and Et Voila!:

Call me a geek, but I watched every second of those two hours!  I got real lucky on this as the boat bottom just about fell off the table at the very end.  And I had maybe 10" of plastic left.  It's really weird watching it bridge huge gaps in space.  The boat looks a lot better in person than in my picture above, not sure why that is.

We honestly don't know how good we've got it with Roger here, he's an amazing resource for all things fabrication.  Thank you Roger!  Stay well everyone!

Hehe, I was about to mention that thing, I know someone who has this, wasn't  sure how well suited and for what exactly of your prototype building it might be. After all, it can't do that big parts, although one could print interlocking parts to make one bigger part I guess.
What *do* you actually plan to do with it?

There are some funny materials out there, someone on YT printed rubber shoes and ran in them. (I have a feel I mentioned this before somewhere).

More impressive than the boat I found a gearbox that actually worked, once some grit inside was removed.
I guess you are aware of thingiverse.com?

Apparently, with a bit of hacking, one get get Fusion 360 to run in Wine:
https://gist.github.com/probonopd/0fab254aa0b6fc371d8db641822bd530
I haven't looked in a while, but last I checked there was no nice open source mech CAD program out there...
Unless you like it procedural: https://www.openscad.org/
Some people make the IMO pointless attempt to use Blender with some trickery to enter somewhat precise units and all that... but it's just not a solid-geometry model program, it's for smoke & mirrors stuff.

Anyway: One thing I remembered from trials was that a print can become bad if there is air draft from open windows that cools parts of a thing being printed. E.g. might skew.
Also sometimes things would not stick to the plate and go loose and it was ruined, influenced by plate temperature. There is an optional plate from a different material I believe. Or was it just a mat... don't remember.
For a plastic material that melts at a higher temperature than the cheapest stuff (when printing, as well as when stored in your car in the summer!) also is harder to work with, some build an enclosure (plexi glas?) with somewhat higher, more stable / controlled temperature inside than just having it stand around in a big room.
Takes some experience to know what kind of density of "3D cobweb" structure you need for something to be as stable as you need it.
And to get a feel for making a repeatably stable process for certain requirements.
And one needs to not forget that you can't apply the same force in all dimensions without it snapping.
How well the layers stick to each other, I imagine, would be influenced by how quickly the ambient temperature cools down the spot just printed & how much it manages to still melt the cold layer's spot under it.

And I, too, watched the first print in full

EDIT:
Apparently, bed height adjustment is critical for good results. And easiest to get right in the beginning is PLA material.

Ah, right, there are a few things (the designers of them think might be able) to improve the device - by printing the parts for itself, by itself.
Just make sure you don't go so far to enable the thing to self-replicate and unleash the apocalypse of zombie printers!

https://www.thingiverse.com/thing:2920060

https://www.thingiverse.com/thing:2917932

https://www.thingiverse.com/thing:2858209

https://www.thingiverse.com/thing:2935204

As for staying well - I have here a few pounds of dark chocolate, and bought a bunch of extra packs of T-paper, well before the inevitable mass hoarding started.
So if they further decrease the freedom of movement, well, I'm ready!
(so far we're still going to work, a guy who was in Italy and tested negative still isn't allowed to come, others who usually are in a sports team or music group don't do such activities anymore, schools, kindergarten closed, cashiers in supermarkets now have plexi glass spit barriers in front of them and wear gloves - no idea how much remains for someone to infect colleagues (with high chance), other than outright reckless behavior now, but let's see.)

"Ah, right, there are a few things (the designers of them think might be able) to improve the device - by printing the parts for itself, by itself."  - tinkeringdude

Thanks!  I'm watching a lot of excellent videos by "Teaching Tech" - this one's a little dated, but covers many of those self-printed upgrades:

https://www.youtube.com/watch?v=fq2IKp3jeaY

"...cashiers in supermarkets now have plexi glass spit barriers in front of them and wear gloves"

Talk about being on the front lines!  I think I'd have to quit that job...  I read an absolutely hair-raising article on Covid-19 last night:

https://www.propublica.org/article/a-medical-worker-describes--terrifying-lung-failure-from-covid19-even-in-his-young-patients

An excerpt (my bold):

"The ventilator should have been doing the work of breathing but he was still gasping for air, moving his mouth, moving his body, struggling. We had to restrain him. With all the coronavirus patients, we’ve had to restrain them. They really hyperventilate, really struggle to breathe."

Ventilators set to 11 for weeks blowing out lungs, with everyone on them restrained, ye gods...  It's no wonder they don't let relatives see what's going on back there.

Flu, my ass.  We just got two cases reported yesterday in my little town of 8000.  This is like a nightmare, I can't believe the US took so long to ramp up testing, it's absolutely criminal.