Electronics for Theremins – 1

Posted: 2/7/2011 4:59:55 AM
FredM

From: Eastleigh, Hampshire, U.K. ................................... Fred Mundell. ................................... Electronics Engineer. (Primarily Analogue) .. CV Synths 1974-1980 .. Theremin developer 2007 to present .. soon to be Developing / Trading as WaveCrafter.com . ...................................

Joined: 12/7/2007

**REMOVED**

Posted: 2/7/2011 7:59:37 AM
coalport

From: Canada

Joined: 8/1/2008

Fred, posting your ideas in a public forum will not protect them from those who might want to "lift" them, patent them, and then claim proprietorship.

If you were to post an un-copyrighted original musical or literary work, and if this work was later taken from the internet and used by someone else who claimed authorship, you would certainly have grounds for a lawsuit, but IDEAS are something else.

The only thing posting an idea to a public access website (like Theremin World) would do, is protect, under certain provisions of the Berne Convention, the written expression of the idea, but not the idea itself.

Posted: 2/7/2011 3:56:42 PM
FredM

From: Eastleigh, Hampshire, U.K. ................................... Fred Mundell. ................................... Electronics Engineer. (Primarily Analogue) .. CV Synths 1974-1980 .. Theremin developer 2007 to present .. soon to be Developing / Trading as WaveCrafter.com . ...................................

Joined: 12/7/2007

**REMOVED**

Posted: 2/7/2011 4:47:39 PM
FredM

From: Eastleigh, Hampshire, U.K. ................................... Fred Mundell. ................................... Electronics Engineer. (Primarily Analogue) .. CV Synths 1974-1980 .. Theremin developer 2007 to present .. soon to be Developing / Trading as WaveCrafter.com . ...................................

Joined: 12/7/2007

**REMOVED**

Posted: 2/7/2011 6:18:49 PM
GordonC

From: Croxley Green, Hertfordshire, UK

Joined: 10/5/2005

[i]I wonder if there is anywhere in the universe which has a 'nice' version of evolution !?[/i]

We are all composite creatures, made up of billions of individual cells that live and die, each of which has evolved to function as a specific component within the body, and which depends on the others for its survival.

(Sponges, which predate us by a long time and have less highly specialised cells, can be put through a blender, separating every cell, and will reform just as it was pre-blending.)

Without evolving cellular co-operation and dependancy there would be only single-cell life.

Similarly we, like many other species, have evolved into communities.

Nature is by no means exclusively red in tooth and claw.

Do any of the open source communities on the 'net offer advice to the inventor who cannot afford the protection of the law?
Posted: 2/7/2011 6:44:05 PM
FredM

From: Eastleigh, Hampshire, U.K. ................................... Fred Mundell. ................................... Electronics Engineer. (Primarily Analogue) .. CV Synths 1974-1980 .. Theremin developer 2007 to present .. soon to be Developing / Trading as WaveCrafter.com . ...................................

Joined: 12/7/2007

**REMOVED**

Posted: 2/8/2011 8:16:55 PM
FredM

From: Eastleigh, Hampshire, U.K. ................................... Fred Mundell. ................................... Electronics Engineer. (Primarily Analogue) .. CV Synths 1974-1980 .. Theremin developer 2007 to present .. soon to be Developing / Trading as WaveCrafter.com . ...................................

Joined: 12/7/2007

**REMOVED**

Posted: 2/28/2011 7:13:47 PM
FredM

From: Eastleigh, Hampshire, U.K. ................................... Fred Mundell. ................................... Electronics Engineer. (Primarily Analogue) .. CV Synths 1974-1980 .. Theremin developer 2007 to present .. soon to be Developing / Trading as WaveCrafter.com . ...................................

Joined: 12/7/2007

**REMOVED**

I will not be visiting or contributing to TW much in 2013, and am unlikely to be replying to any threads.

Please feel free to contact me by email.

My email address is shown on my avatar.

it is:

fred

at

fundes

dot

co

dot

uk

Posted: 5/24/2011 11:37:42 PM
torceador

From: Mountain View, AR

Joined: 5/24/2011

MC14584 Serendipity

I was interested in the Glasgow digital theremin front end, to create a control voltage to put through a PIC-based Fourier synthesis engine I'm playing with. I didn't have any CD4093s in my junkbox. After I ordered some, I still wanted to tinker with the concept while I waited. I had some MC14584 chips which were also CMOS Schmitt trigger hex inverters with an identical pinout, so I made up a pitch and volume oscillator. I used the 15K Ohm resistor and a 22pf mica capacitor as shown on the schematic.

The oscillators fired up immediately at over 6 MHz. I thought whaaa? After a quick look at both data sheets, I found that the MC14584 Schmitt trigger voltage levels were a lot closer together than the CD4093. Hmmm. I increased the resistor value to 330K Ohm, and got the pitch oscillations around the 500 KHz area when I had an oldtemecula 'Lev' antenna connected.

With the voltage swing smaller, and the resistance about 20x greater, this oscillator is SENSITIVE. I get an initial frequency delta at about five feet. The total swing I get is 20-25 KHz. This may be WAY too sensitive to use its direct mixed output for a musical instrument, since Clara's instrument is really the least sensitive of popular ones, but if you are simply looking to maximize sensitivity, I've not seen any pitch oscillator with this much delta.

The CD4093s have come in, so I'll fab them up and just see which is more useful after going though the mixer/tachometer section of the Glasgow design. I hope I can get a fairly linear slope out to utilize.

This will be my first digital attempt at a Theremin. Thanks for starting the thread.

torceador

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