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

Yikes!  I was fine until the octave shifts.

"Yikes!  I was fine until the octave shifts."  - pitts8rh

Yeah, that final +3 can really tweak your auditory subsystems!  You were warned! ;-)

Notice though, amidst all the ear bleeding, that there's no audible aliasing (something I've worked diligently to minimize).

[EDIT] It's interesting to set the octave to +3 and take quick swipes at the pitch plate, which leaves the oscillator phases in random states: [MP3].

Playing The Damned Game

I know that I haven't brought anything to market, but at this point I do have some observations regarding what it takes to be a Theremin designer.  Here's the bare (damned) minimum IMHO:

#1 : You have to be able to play the damned thing.
Even if it's just a barely recognizable "Mary Had A Little Lamb" there's no excuse for a designer to not be able to play.  Would you buy a guitar from a luthier who couldn't play?  Would you buy a harpsichord from a builder who couldn't play?  Can you really trust a piano tuner who can't really play?  Theremin himself could play quite well, and toured the world giving concerts.  Moog could play.  Dominik can play.  Thierry can play.  Urs Gaudenz can play.  Art Harrison can play.  Even I can play (after a fashion).  Development is a great time to learn, actually, so if you can work your practice into that you're killing two birds.  Designers who can't play have no way to gauge any feedback they might get.  And you need to be able to do a proper show-and-tell for anyone who will listen.  You'll be forever searching for others to showcase your design if you can't be arsed to learn how to play it even a little.  I mean, come on, have a little respect for your creation.

#2 : You have to be able to read and draw a damned schematic.
Who decides to be an author thinking "I don't need those pesky written word things"?  Who goes into symphonic composing thinking "I can't be bothered with those stupid note symbols"?  It's absurd on its face.  If you can't read a schematic you can't easily tap into the vast knowledge that's out there, and job one is scouring every schematic you can get your hands on for insight.  If you can't draw a schematic you can't convey your own thoughts and ideas to others, which will likely frustrate all involved.  If you never learn to read and draw a schematic you'll be forever searching for others to interpret your (probably lame) designs.  Schematics are the bread and butter of electronics for entirely practical reasons, avoid them at your extreme peril.

#3 : You have to be able to take some damned criticism.
All criticism (unless it comes from a fanboy or a hater) is useful.  The customer is in some sense always right - certainly if they are taking the time to tell you something then you should listen.  You're building a musical instrument, where feelings and emotions can run high.  You're designing something electronic, and there will always be people who understand elements of your design better than you do - that's just a fact of life.  If you can't take even gentle constructive criticism from players and your peers, this isn't the field for you.  You should go way out of your way to get all the feedback you possibly can, and negative feedback is probably the most valuable, should you choose to heed it.

#4 : You have to be able to live in this damned reality.
Do magnets seem like magic?  Yes!  Does radio seem like magic?  Yes!  Does precision capacitive sensing at a distance seem like magic?  Yes!  But they're not!  All have been adequately explained by physics for quite some time now.  At the end of the day, a Theremin is a small pile of electronic components, no more, no less.  You would be right in your expectation to be able to replicate it 100% if given the components and the schematic and some instruction, so where's the room for magic in that?  It's god of the gaps, and all the gaps in the physics of electronics closed long ago.  If you can't accept this corner of reality, then you have no business in this business.  This is a golden age of information, there's little excuse for absolute ignorance if you have the desire to understand, an internet connection or decent library near you, and some time on your hands.

#5 : You need a damned oscilloscope.
You'll be flying blind without one.  2 channels are enough.  It doesn't have to be fancy, but don't throw your money away on a toy.  You also need an OK quality DMM, and if you're winding coils you need an inexpensive LC meter.

Dewster, I like your thoughts.

I think you are more of a creative and developer than a businessman. Marketing of a product belongs on another frames. Beware there is a need of the new product. What is the unique selling proposition?

You need the best players, or at least some entusiastic promoters for the new development. That costs a lot of money, nobody deals without advantage for himself. 

"I think you are more of a creative and developer than a businessman." - JPascal

You're right.  Though I do think I can handle the business side, particularly if it is rather one-off.

"Marketing of a product belongs on another frames. Beware there is a need of the new product. What is the unique selling proposition?"

Linearity (the real deal, not "ideal")!  Many acoustic and woo-woo voices!  Ease of ownership (no internal calibration)!

"You need the best players, or at least some entusiastic promoters for the new development. That costs a lot of money, nobody deals without advantage for himself."

But first, I need a cabinet! ;-)  A cabinet, a cabinet!  My kingdom for a cabinet! 

The eternal - and very real - problem is cabinetry, which is ergonomics made flesh.  Many (most?) designers don't seem to put adequate time into this IMHO.  E.g. most Moog products place the knobs at your navel.  The Pro is really pretty, but I'm not sure I'd take one even for free (well, sure, for free - I'd play with it for a day or two, open it up and photograph it, then sell it - like I did with the Theremini).

I think the fact that you have gone from knowing nothing about theremins (at some point I'm sure this is true) to having created the D-Lev to its present level of refinement shows that you are probably capable of doing anything that you set your mind to. It's not like you have had a great deal of community support as this evolved, although you've had plenty of critiquing by those that have never had a chance to try it out. 

But when it comes to the other areas of expertise needed to get something to market, or at least available in some form even if only on a custom basis, it would make sense to ask if you should even try to set your mind to them or open up to acquiring some help.

There are the things that that for now only you can do - continued development and maintenance of software, support, and writing a detailed user manual which should probably have some heft to it given that there is quite a bit of depth to the UI, and many examples and intuitive tips are needed.   And regarding product support, think about how much time you spent holding my hand to get my prototype to this point.  Of course the stability of the design and availability of that TBD manual will change the game quite a bit, but I could see a large amount of time spent supporting your next customer.

Then there are the tasks that you could offload (or not): board design, cabinet design & fabrication, and assembly, among others.  If you do all of these things you may get spread a little thin.  We have already talked about what would be necessary to come up with a releasable board set and I'm flexible on helping with that if I get the software that I need, although I'm becoming notoriously unreliable these days with both age and my own to-do list getting in the way :|. 

But the other things may be a problem....

But first, I need a cabinet! ;-)  A cabinet, a cabinet!  My kingdom for a cabinet! 

I think about this a lot, trying to look at some path that would work for you.  There is a conflict here between an easy and attractive design, and designing and fabricating even what would be considered an "easy" Etherwave-style enclosure is I think more than you want to do yourself. Yes, you can do it, but do you want to? You have to like fabrication, and if you don't you should farm it out.  I'm a woodworker, but there is still a lot of tedious work involved in building multiples of any given thing.

I had hoped to help with this part of the project but it's pretty clear that we don't have much common ground on what the cabinet should look like.  We'll never even agree on the issue of plates versus rods, even though a cabinet could certainly be designed to have either option.  I know that you have had a desire to take a fresh or even radical approach to the enclosure design, and that's very much needed considering what else is or was out there (except for Moog designs). But I would be cautious that going so far as having an aversion to the traditional rod and loop might be against your own best interests. I do think you need to have more outside feedback on this; certainly more than mine, and not just your own gut, because going the wrong way here could be a deal-breaker for some I am sure. 

I know that you would agree that it would be beneficial some design help on this, even if only as "hired help" to actually just do the work to implement your own design concept.  In my opinion the D-Lev is fundamentally a solid and capable theremin design and deserves something unique and attractive, preferably without plumbing fittings or anything that obviously looks like it was adapted from parts found at Home Depot. But we've been over this, and that dead horse is indeed dead and has suffered enough.

It comes down to 1) doing yourself, 2) paying someone to do it for you, or 3) finding an enthusiastic, skilled, and altruistic partner that's willing to make your vision turn into reality for the good of theremin-kind. And there are problems with all of these whether it's financial investment with little hope of return on this niche product, or conflict or potential loss of control and rights by opening up to another party.  I've always been an advocate of #1, but this theremin needs to get packaged up and in the hands of at least a few more users soon, and it takes time to do everything serially.  Some fresh feedback from other users might confirm that it's ready or in need of something that has been missed.

Anyway, we've had these discussions before, so I'm probably not adding anything.  But I'm pretty sure that the enclosure problem isn't going to be solved by off-the-shelf items unless you are very good at disguising your work. It would be nice if you could get more player feedback on some of the ergonomics issues. Even though this thread is often at the top of the Recent Posts, I know of several users that have no idea what a D-Lev is and have never read the thread at all.  Perhaps it would be helpful to start a new player-oriented thread in some other category?  

"There are the things that that for now only you can do - continued development and maintenance of software, support, and writing a detailed user manual which should probably have some heft to it given that there is quite a bit of depth to the UI, and many examples and intuitive tips are needed."  - pitts8rh

Nice post!  I'm not planning on shirking my duty on the manual, but have you glanced at the Theremini manual?  It's almost nothing, and the synth in there might be around the same complexity, though its axis settings are quite a bit less comprehensive.  Anyway, the improvement to LibreOffice have me stoked again regarding documentation, and the open office format hopefully means it they might survive in an editable form for a while.

"I'm a woodworker, but there is still a lot of tedious work involved in building multiples of any given thing."

All the physical stuff can get tedious.  I just stuffed the main and tuner boards you kindly sent and that took most of the day (though some of that was removing parts from the first prototype, and repairing the pins I snipped long ago).  Board stuffing can happen while other things are going on (paint drying, etc.) but I was hoping for more like 1/2 day for the electronics.

"...I'm pretty sure that the enclosure problem isn't going to be solved by off-the-shelf items unless you are very good at disguising your work."

I'm not currently planning on using plumbing or commercial boxes or other stuff, for the main reason that nothing out there seems usable, and then there's the prop department issues, as you point out.

"It would be nice if you could get more player feedback on some of the ergonomics issues."

Amen!  I'm not intentionally dragging my feet, but it seems the cabinetry has to be more nailed down than it is before I can mail a demo somewhere.  First impressions are unfortunately all too important, even at this stage.  I have an idea for the configuration of the elements that might be a finalist, will post a sketch soon.  Having the second prototype has emboldened me to dismantle and use parts from the first prototype in a third.  I'm not 100% happy with the second prototype, but it's playable and the ergonomics are OK.  It's interesting to go from it to the first prototype, which makes it clear that the plates on the first were spaced somewhat too far apart, and the pitch plate too low.  As it's just a box, prototype 2 could be fairly easy to build, and it could accept any type of antenna, and who knows, maybe that's where things will end up.  But I don't like the plates hanging out in space where they are easily damaged, and I don't like the coils inside the box as they themselves are C sensitive, so ideally would be co-located with the antennae.

Out With The Old...

Seeing as how I have a comfortably working second prototype (P2 - many, many thanks to Roger for the stuffed PWBs!), I figured it was high time to cannibalize the first prototype (P1) and work on a third (P3).  The DuPont wiring in P1 was becoming increasingly cantankerous connection-wise, and having too many FPGA pinouts skulking around gets real confusing real fast (version control is a job, I tells ya).  The end of an era, good ole P1 went to Theremin heaven, he was a jolly good fellow, and so say all of us (*sniff*).  In a century, the docents at the dewster museum (& nail salon) will have to inform all (2) of the visitors gazing disappointedly at shoe boxes on a stick: "No, sorry, that's not the real P1, but a mock-up of what we think it probably looked like.  P1 was destroyed when the inventor rashly decided to use parts of it to construct the disastrous P3, and the rest is history.  Which reminds me: your tickets get you into the Titanic museum across the street at half price."

In With The New...

At my request, Roger exceedingly kindly sent me some of his PWBs (For free!  Along with a bunch of other cool stuff!) and I populated the main and tuner ones with many of the components from P1 (LEDs, ICs, some passives, along with physical components Roger provided like connectors and such), then repumped the FPGA and EEPROM with the latest FW & SW loads - success!  The LCD is just supported by the pins at this point.  The CAT5 cable end is cut off and wired directly to the tuner, something I may do again (unless someone stops me!) as it makes the connection angle more manageable.  Coming to a prototype near you!

Next up is populating the encoder PWBs, connecting them (via DuPont), and hooking up the old AFEs & plate boxes to make sure it's 100% functional.  Then on to a new P3 physical configuration that the world has never before seen, nor could even imagine (insert maniacal laughter here). (I keed.)

I'm In The Mood

It's pretty easy to play - I heard it last night in a movie and picked it up today without really even trying: [MP3] (with some added reverb).

Because of the Theremin I'm seeing these hokey old songs in a different light, they have really nice melodies.

dewster that was very nice, a timbre to die for. It brought back memories.

Christopher

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