Child Proof Theremin

Looking for plans to build a child proof theremin that would be located in a children's museum.  Mostly concerned with children bending or breaking off the antenna(s).  Does anyone have any plans or ideas that would work in this environment?

Plates. See e.g. Harrison Instruments 302 (which I haven't played but there's a guy here who can tell you all about it)

Plates. See e.g. Harrison Instruments 302 (which I haven't played but there's a guy here who can tell you all about it)

Thank you very much.  This looks possible, but may be out of the budget.  Was looking maybe for a low cost home built possibility.

Mike welcome to the madness,

Keeping a theremin in tune is the biggest issue; I used a remote method so the docent could check and tune it from her desk. I had the oscillators lock onto one another around 100 Hz so it was quiet when no one was around.

For a child you need a Pitch only theremin as Volume control serves no purpose. They are not going to be making music just fascinated by the sound effect.

When I did the theremin in my Imagination Workshop I used a large mirror with a nice frame. As the kids approached and peered through the looking glass the Pitch rumble very low as I divided the audio signal by four so 200 Hz is heard as 50 Hz. This was mounted on a 4” wood platform with speaker/sound transducer so the floor would shake.

What you are doing is not a simple project yet can be magical. Most engineers fail at theremin design as it is more complicated than they imagined and often outside of the realm of their knowledge. I admire your enthusiasm. You need to have advanced electronic building skills with a little woodworking thrown in?

If you were local to me I could help a bit more but Father Time has taken his toll.

Christopher   
www.Hwy79.com

dewster why do you always go weird on me? You got six months left.
.

"Most engineers fail at theremin design as it is more complicated than they imagined and often outside of the realm of their knowledge."  - oldtemecula

Too bad Theremin was an engineer, imagine the wondrous instruments he could have built if only he (like yourself) had known almost nothing about electronics.

Mike, maybe the Thierrymin with (as bendra suggested) a plate antenna:

http://www.thereminworld.com/forums/T/29231?post=201239#201239

I would electrically insulate the outside of the plate to help keep ESD from killing it.

dewster said:  “Too bad Theremin was an engineer, imagine the wondrous instruments he could have built if only he (like yourself) had known almost nothing about electronics.”

dew - You need to move beyond insulting people and always posting unproven ideas.... demonstrate something that actually works properly.
-----------

In Moscow 1979 Lev Sergeyevich spent his time in his shop in an attic of the Department of Physics building. His Theremins including the most complicated one, which to the best of my knowledge, was never finished. Could it have been the foundation for the Phoenix?

Many of Lev Sergeyevich Termen's later theremin experiments through the 70's & 80's were built using parts from the toy department (Detskii Mir) in Moscow and at this time nobody in Moscow was interested in his work. He actually slept in his lab in the attic and had a pet mouse which he trained to come out to the certain tone of the Theremin!

Edited: Leon Theremin’s grand-son is very active in the theremin community today and will read this and maybe add a little more to this short story that happened before he was born. All of the components in my own original Classic design Leon Theremin was very familiar.......... 

Christopher
www.Hwy79.com

Edit: In a museum today I would use the Volume Control side circuit only which brings up a prerecorded sound or tune when approached. This way the docent will know when it is out of tune as she will hear it and then remotely make an adjustment to quiet it back down.

Another project approach is in the digital realm using an Ultra Sonic transducer. Just call it a theremin as who is going to know. Then have it make goofy nasal or kazoo sounds when approached. This would not need tuning so maybe the best idea yet.

Edit2: ILya I always admired Natalia Theremin who is beautiful. When I wrote that it was her birthday, maybe I revealed too much.
.

"Two of Leon Theremin’s grand-sons are very active in the theremin community today"  - oldtemecula

I know just one (grand-grand-son), who is the second?

You're hiding something!
Мaybe yourself had a secret romantic relations with a Theremin’s daughter?

Child-proof Theremin, eh?

Install a sound playing module in the Theremin that, upon too close contact of a child, being identified by a camera + AI in one corner, would make the device say: "If you touch me, you're going to eat brussel sprouts with spinach sauce for the next three weeks".
That ought to do it.
Oh wait... not that kind of child proof?

I guess a plate antenna has different characteristics from the classical ones, and may not easily fit classical designs one is looking for, so there would be more EE design effort, or not so classical open source circuits need to be used?
(I don't know, just wondering - an EE might easily suggest something which requires this without thinking much of it. I know nothing about the background of the OP, but it could add burden)

Would it be feasible to put the pitch antenna into a thick plexiglas pipe with somehow rounded-off top lid,
and plexiglas walls around the volume antenna with, if necessary, the center part cut out to be able to grab into the loop for max coupling?
Kinda like some graphics cards have the plastic shield around the electronics, with a circular cutout for the fan.
Especially the classic volume loop antenna looks kinda cool. (although I guess one could design neat looking plate things, too - just not square, literally, hah)

I disagree that building basically one of those good-for-nothing toy Theremins with only a pitch antenna would be a good idea.
It would mean that you can switch this either hard off or on, and when it's on, it's making noise, all the time. I don't know for how long the children might find this funny, but the accompanying adults, and especially people working in the museum, probably not so much.

I'd just make the polarity of the volume antenna such that getting closer to it makes it louder, i.e. if nobody is standing close to it, it is quiet by default, i.e. most of the time.
And I'm not sure why changing the volume of the sound with touchless hand movements would be any less fun than changing the pitch to kids. They're not going to play proficiently either of those aspects at first (lack of, haha) contact. But I guess it's easy enough to keep the left hand somewhat still to play roughly at constant volume and concentrate on the pitch hand when desired. At least I found it easy on the EW Standard.

"I guess a plate antenna has different characteristics from the classical ones, and may not easily fit classical designs one is looking for, so there would be more EE design effort, or not so classical open source circuits need to be used?  (I don't know, just wondering - an EE might easily suggest something which requires this without thinking much of it. I know nothing about the background of the OP, but it could add burden)"  - tinkeringdude

For this application I'd pick a simple Theremin oscillator circuit (without series EQ) which would be largely agnostic regarding antenna area / geometry.  A plate would probably increase the interaction distance, which would make for a more impressive installation.

"I'd just make the polarity of the volume antenna such that getting closer to it makes it louder, i.e. if nobody is standing close to it, it is quiet by default, i.e. most of the time."

That's a great suggestion!