Special Project! Need a Theremin with a big radius of sensitivity and MIDI output!

Hi friends!

I have an old BigBriar Theremin kit and cherish it deeply.  I never modded it for CV output, but now I have a big art project and I'd like to integrate a theremin into it.  The project is a sculpture lit by video projectors.  I want to change the video with a signal coming from a theremin inside of the sculpture.  

TLDR: the closer one gets to the sculpture then affects which video clips are projected.

Questions:

- Can I use my BigBriar Theremin to make a CV output and then convert that to MIDI for the video software?
- Can the capacitive field be "enlarged" so that the theremin begins to react from about 5-8 feet away?
- Is the BigBriar stable enough to use or do I need something more modern that won't drift out of tune / sensitivity?

I enjoy your enthusiasm but like most engineers you have a very weak understanding of what the Theremin Phenomenon is about or how it works.

An approach that might work for you is a forward facing ultrasonic sensor or two. As you get closer (10’ to 1’ or 3.5m to .5m) a voltage level in the circuitry can rise like 1v to 5v volts that can be used to trigger the response you want.

The fact that you have to ask others to design your invention for you is not very encouraging of your skill level to accomplish this task or art.

I do wish you the best of success.

Christopher

Conventional, classic theremins will not cope with this task. They operate in a very small space. 0.5...1 meter.

"- Can I use my BigBriar Theremin to make a CV output and then convert that to MIDI for the video software?"  - JSPorter

Kinda round about, but possible.  Might want to look at the Etherwave hotrodding paper for the CV portion.

"- Can the capacitive field be "enlarged" so that the theremin begins to react from about 5-8 feet away?"

I think this requires a larger surface area "antenna" for interaction, which perhaps requires a larger value coil to keep the Q and voltage swing high.

"- Is the BigBriar stable enough to use or do I need something more modern that won't drift out of tune / sensitivity?"

The farther out you want the interaction, the more touchy the nulling will be.  I was approached by someone who was embedding Theremins in interactive sculptures, but long-term nulling was a huge problem.  I designed an auto-nulling mode for the D-Lev which solved the problem, and it can auto-switch the voice too when the person steps away far enough.  Full featured MIDI out as well, but the internal synth was sufficient for his needs:

I enjoy your enthusiasm but like most engineers you have a very weak understanding of what the Theremin Phenomenon is about or how it works. An approach that might work for you is a forward facing ultrasonic sensor or two. As you get closer (10’ to 1’ or 3.5m to .5m) a voltage level in the circuitry can rise like 1v to 5v volts that can be used to trigger the response you want.The fact that you have to ask others to design your invention for you is not very encouraging of your skill level to accomplish this task or art.I do wish you the best of success.Christopher

Christopher, your flat rudeness is not very encouraging for my introduction to this community.  Did Clara Rockmore have a "strong understanding of the Theremin Phenomenon" in order to create her art?  In my interpretation a forum like this is designed for question, education and the dissemination of knowledge.  As an artist my job is to have a strong concept and to communicate that concept as best as possible.  I reach out to those more informed as I have done here in order to find answers to execute the creative pursuit.  Those honest questions of mine are part and parcel of the creative process.  Attitudes like yours are deeply disappointing and do not serve to breed innovation and growth. Other engineers have been far more encouraging and have some interesting theories about antenna and circuit modifications that would indeed enhance the capacitive range of the Theremin.  Will it work? I don't yet know, but here I am making an honest effort to investigate.  Please feel free to "contribute" elsewhere.

"- Can I use my BigBriar Theremin to make a CV output and then convert that to MIDI for the video software?"  - JSPorterKinda round about, but possible.  Might want to look at the Etherwave hotrodding paper for the CV portion."- Can the capacitive field be "enlarged" so that the theremin begins to react from about 5-8 feet away?"I think this requires a larger surface area "antenna" for interaction, which perhaps requires a larger value coil to keep the Q and voltage swing high."- Is the BigBriar stable enough to use or do I need something more modern that won't drift out of tune / sensitivity?"The farther out you want the interaction, the more touchy the nulling will be.  I was approached by someone who was embedding Theremins in interactive sculptures, but long-term nulling was a huge problem.  I designed an auto-nulling mode for the D-Lev which solved the problem, and it can auto-switch the voice too when the person steps away far enough.  Full featured MIDI out as well, but the internal synth was sufficient for his needs:

Thanks so much for this! I do still have the "Hotrodding" paperwork for this.  In fact, I ordered this from Mr. Bob Moog himself in about 1998 and was honorerd enough to have a brief conversation with him on the phone!  This is valuble input.  I'm going to experiment with extending the antenna first.  For now, I've ordered a Theramini to play with as it has built-in MIDI over USB.  If the range turns out to be so limited, I think it can still be an effective creative piece and I would rather still include a Theremin circuit than turn to other options.  The personal value of using a Theremin is far more charming than laser or ultrasound.

Not being a native speaker, it's hard for me to judge the presence of rudeness, but everything Christopher said was on point and correct.

1. The teremin is not designed for the kind of tasks you suggest, and Christopher offers an adequate alternative.

2. It is sacrilege to use a termenvox for anything other than music. It's like asking violinists on a specialized forum how best to scare cats with a violin.

And I'd also add that Christopher has been around for a very long time and has a lot of experience.

"Thanks so much for this! I do still have the "Hotrodding" paperwork for this.  In fact, I ordered this from Mr. Bob Moog himself in about 1998 and was honorerd enough to have a brief conversation with him on the phone!"  - JSPorter

Wow, that's pretty awesome!

"I'm going to experiment with extending the antenna first."

Try a plate too, maybe something the size of a car license plate.  You'll definitely have to retune it.

"For now, I've ordered a Theramini to play with as it has built-in MIDI over USB.  If the range turns out to be so limited, I think it can still be an effective creative piece and I would rather still include a Theremin circuit than turn to other options."

The Theremini has really weak fields and uses tons of averaging in an attempt to repair the damage.  You might look into the Open Theremin, I believe it also has somewhat weak fields, but you could probably hack the software to do continuous nulling.  It has MIDI out as well, and is quite inexpensive.

"The personal value of using a Theremin is far more charming than laser or ultrasound."

I agree.

Not being a native speaker, it's hard for me to judge the presence of rudeness, but everything Christopher said was on point and correct.1. The teremin is not designed for the kind of tasks you suggest, and Christopher offers an adequate alternative.2. It is sacrilege to use a termenvox for anything other than music. It's like asking violinists on a specialized forum how best to scare cats with a violin.And I'd also add that Christopher has been around for a very long time and has a lot of experience.

I'm moving forward.

Not being a native speaker, it's hard for me to judge the presence of rudeness, but everything Christopher said was on point and correct.1. 

Christopher made the right point, but the way he expressed it was disrespectful. He indiscriminately belittled the intellectual level of ALL engineers wholesale. Why? This is not a healthy generalization. I believe this is what JSPorter defined as rudeness. Fair enough in my opinion)). But of course, in my opinion, it was not something very offensive. Moreover, it was a proposed implementation option for the requested task.
I suggest we write this off as inevitable forum errors and leave it in the past))