Trying to build a pitch theremin for a school project

Posted: 4/25/2015 11:44:43 PM
tl314

Joined: 4/25/2015

Im trying to find a schematic for this thermin 

https://plus.google.com/u/0/116802649841922513393/posts/BiLEaedygmt?pid=6141825474042479282&oid=116802649841922513393

so I was wondering if yall knew how to do it or could point me in the direction to one similar. I need to build one for a school project. I built a simple optic one but the teacher said I need another that was different. Please any help would be great.

Posted: 4/26/2015 12:20:17 AM
oldtemecula

From: 60 Miles North of San Diego, CA

Joined: 10/1/2014

Why did your teacher not like your Optical Theremin?

I began my journey with a simple optical design, then after finding Clara's voice in the vacuum tube years later I am now (today) revisiting the Optical method for something between a Tannerin and the actual theremin. I am still working out the best approach hoping for input from builders.

Optermen II

Thierry has what you may be looking for.  He is the only engineer I trust today.

 Therrymin

Give us some feedback on what direction you choose.

Christopher

Posted: 4/26/2015 1:30:31 PM
rkram53

From: Northern NJ, USA

Joined: 7/29/2014

Thierry,

You spend so much time on this and then more time answering questions - which is extremely wonderful of you - but I'm curious, why don't you just make a run of PCBs and sell them at the same source you do your ESP modules. You could even package up the parts as a kit with instructions. Likely will be very light so it could mailed around the world without too much extra cost that you would include in the price. It's not out of the question that with the growing interesting in the theremin, this might be included in a lot of high school science curricula - not to mention a ton of folks just wanting to buy it for personal enjoyment.

Seems to me you are the one person in the world who is in the ideal position of creating a company to make world class Thierrymins. 

Rich

 

Posted: 4/28/2015 8:57:41 PM
tl314

Joined: 4/25/2015

i tried building this one but I cant seem to get it to work. 

http://www.thereminworld.com/pics/schematics/simple.jpg

for my output i have a 8 ohm speaker with the black wire hooked to output and red to power rail, for antenna i just have a wire

Posted: 4/28/2015 9:23:32 PM
oldtemecula

From: 60 Miles North of San Diego, CA

Joined: 10/1/2014

tl314 Said: for my output i have a 8 ohm speaker with the black wire hooked to output and red to power rail, for antenna i just have a wire

The digital people will need to give you assistance, maybe a lashing. One hint, the speaker will not get you there, apply the output to an amp or amplified computer speakers.

Good luck

Christopher

 

Posted: 4/28/2015 9:24:32 PM
Thierry

From: Colmar, France

Joined: 12/31/2007

That's normal that it does not seem to work. With a little bit of basic knowledge in electronics, you would understand that you can't hook an 8 Ohm speaker to the output of a CMOS circuit, especially if there is still a low pass filter with a inner resistance of 10kOhm in-between. The 10k resistor forms a voltage divider with the 8Ohm speaker.

The 4077 outputs a signal with 9Vpp which corresponds to 2.25Veff since the audio component is a triangle signal. With 8 Ohms after the 10k resistor, there remains a voltage of 2.25 * 8 / 10008 = 1.8mV which gives an output power of 0.4 uW which is inaudible. Thus you have to hook that simple theremin to an audio amplifier which will be capable to drive an 8 Ohm load. You may use an active speaker from a computer sound system and connect the theremin's output to the tip of the audio jack and the ring to GND.

Then you may already have a working theremin but you will perhaps still not yet hear anything because that circuit has so huge tolerances that the audio signal will be higher than 20.000kHz and thus be inaudible. You will have to connect a frequency counter to pin3 of the first 4093 (the one with the antenna at pin 2) and note the measured frequency. Then you connect the f-counter to pin3 of the second 4093 (the one with the 20k pot) and adjust the pot for a frequency which is equal or only slightly higher (max. +100Hz) than the first reading. That is very tricky and you should use a 10 turn precision ceramic potentiometer for that.

Repeat both measurements and the adjustment a few times and you will (if you made no other mistakes when building the circuit) hear an audible but ugly audio signal from the amplified speaker. 

But very first, you should understand that most of these "simple" circuits have not been designed to be built and played, but rather as theoretical proofs of concept. These are developed by engineers, technicians, or freaks (which is often the same), but not by musicians, thus one should never expect to get a properly working music instrument from these waaaaaays too simplified circuits.

Posted: 4/28/2015 9:33:48 PM
Thierry

From: Colmar, France

Joined: 12/31/2007

I have still a few (3 or 4) Thierrymin circuit boards here and I'm ready to give them away to interested people!

The world class Thierrymin will come one day but that will still consume lots of time and money. And since I have to feed a wife and 4 children, I cannot allow to spend to much of both into projects which most probably will never pay fully back as seen with the RCA, the Ethervox, the Etherwave Pro, and the tVox tour, which all were discontinued because the market was too small.

rkram wrote "Thierry,

You spend so much time on this and then more time answering questions - which is extremely wonderful of you - but I'm curious, why don't you just make a run of PCBs and sell them at the same source you do your ESP modules. You could even package up the parts as a kit with instructions. Likely will be very light so it could mailed around the world without too much extra cost that you would include in the price. It's not out of the question that with the growing interesting in the theremin, this might be included in a lot of high school science curricula - not to mention a ton of folks just wanting to buy it for personal enjoyment.

Seems to me you are the one person in the world who is in the ideal position of creating a company to make world class Thierrymins. 

Rich"

 

Posted: 4/29/2015 2:32:56 AM
tl314

Joined: 4/25/2015

I have still a few (3 or 4) Thierrymin circuit boards here and I'm ready to give them away to interested people!

The world class Thierrymin will come one day but that will still consume lots of time and money. And since I have to feed a wife and 4 children, I cannot allow to spend to much of both into projects which most probably will never pay fully back as seen with the RCA, the Ethervox, the Etherwave Pro, and the tVox tour, which all were discontinued because the market was too small.

rkram wrote "Thierry,

You spend so much time on this and then more time answering questions - which is extremely wonderful of you - but I'm curious, why don't you just make a run of PCBs and sell them at the same source you do your ESP modules. You could even package up the parts as a kit with instructions. Likely will be very light so it could mailed around the world without too much extra cost that you would include in the price. It's not out of the question that with the growing interesting in the theremin, this might be included in a lot of high school science curricula - not to mention a ton of folks just wanting to buy it for personal enjoyment.

Seems to me you are the one person in the world who is in the ideal position of creating a company to make world class Thierrymins. 

Rich"

 

how about this theremin then?

http://www.theremin.us/100/minimum.html#Construction

 

Posted: 4/29/2015 6:33:30 AM
Thierry

From: Colmar, France

Joined: 12/31/2007

Art Harrison's Mini Theremin is already a better approach, since Art has proven to build fine instruments which are appreciated by some musicians. But the principle of operation is the same as in the simpler approach before. That means that you will have to amplify the output signal, too, before feeding it into a speaker. You should strictly respect the suggested circuit board layout to prevent interference and other unwanted side effects.

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