Pacemaker and Theremin

Posted: 5/4/2008 2:49:34 PM
Thierry

From: Colmar, France

Joined: 12/31/2007

Sorry for my bad English, but I'll give it a try...

Thresholds for interference resistance of pacemakers:

The fixing of these thresholds comprises static magnetic fields and also elctromagnetic fields.
...

Low frequency fields
The interference threshold of pacemakers is 6000V/m at 50Hz.

Modulated magnetic fields
The interference threshold with modulated magnetic fields in a lower frequency range <10kHz is 80A/m which corresponds to 100uT. The threshold for higher frequencies >10kHz is 1A/m.

High frequency fields
The threshold for higher frequencies will only be given in V/m because there is a fixed relationship between electric and magnetic fields at those frequencies (> 150kHz). Pacemakers resist to a field of 100V/m at their inputs.


Ron, I think you risk nothing with a normal Theremin operating at low voltage. Even if you would be in front of a vacuum tube theremin with an anode voltage of 75V with the tank circuit in the anode circuit at full amplitude (which is never the case!) you would not reach the 100V/m.

So don't worry and enjoy your theremin.
Posted: 5/4/2008 2:50:23 PM
Thierry

From: Colmar, France

Joined: 12/31/2007

Edited / Deleted

(double posting)

Perhaps too much vibrato on the return key... ;-)
Posted: 5/4/2008 5:21:10 PM
Jeff S

From: N.E. Ohio

Joined: 2/14/2005

Thierry...you're begining to stutter. ;-) (That's a joke....double post)

(Not to belittle his condition) another little joke...

If it does happen to have some effect on your pacemaker...that would be one way the "make your heart sing"!
Posted: 5/4/2008 8:27:02 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

"Ron, I think you risk nothing with a normal Theremin operating at low voltage. Even if you would be in front of a vacuum tube theremin with an anode voltage of 75V with the tank circuit in the anode circuit at full amplitude (which is never the case!) you would not reach the 100V/m."

Thierry is absolutely right about this! there is NO chance of reaching anywhere near 100V/m..

A LC oscillator on a semiconductor oscillator is unlikely to output more than about 30V Peak - and this is at such high impedence that touching the antenna will drop this level drastically. The radiated (V/m) signal will tail off following inverse square law .. You have almost no chance of exposing yourself to even 10V/m unless you were to insulate the antenna and insert it into your body.. and even if you did this, you could not reach 100V/m !

I understand your fear - but it is unfounded.. You are being 'blasted' continuously with signals far exceeding what you could ever get from a Theremin.. Even a faulty theremin is EXTREMELY unlikely to put out anything which could cause you any problem.

To be safest and surest, get a Theremin which has passed emmissions testing (anything having a CE mark must far exceed the emmissions criterion required by your pacemaker)

Posted: 5/5/2008 1:52:22 AM
Thierry

From: Colmar, France

Joined: 12/31/2007

[i]"You have almost no chance of exposing yourself to even 10V/m unless you were to insulate the antenna and insert it into your body.."[/i]


Dear Friends, hmmm, no, hmmm, I decided to not to write down my sloppy thoughts after reading this... :-)))
Posted: 5/5/2008 2:28:20 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

"Dear Friends, hmmm, no, hmmm, I decided to not to write down my sloppy thoughts after reading this... :-)))"

Ahhh.. Now I fully understand this (probably wise) reaction...

But may I be so bold as to ask.. Do you agree with my assessment? :-) ?
Posted: 5/5/2008 5:53:39 AM
Thierry

From: Colmar, France

Joined: 12/31/2007

Fred, how couldn't I agree with you?

I want just to note in this context that absorption and attenuation depend strongly on the environment's humidity...

OK, OK, I'll stop now!
Posted: 5/5/2008 9:54:41 AM
Ron Winkler

From: Germany

Joined: 5/1/2008

hello all.

@thierry: thank u for the translation. it is a good one.

in spite of everything i wonder, that i am the lonely only with a pacemaker who is interested in playing the theremin and the influence of the em-fields.

but so what, all my questions are answered and i can start. i will let hear u the results of crossing the sound of my hurdygurdy with the theremin.

greetings
Ron





Posted: 5/9/2008 4:10:42 PM
omhoge

From: Kingston, NY

Joined: 2/13/2005

Yes am also sure you are not the only person with a pacemaker playing theremin, maybe they're just not here or on-line.

But that's great news Ron!

I'm very glad you're getting started with the theremin.
Please keep us posted, can't wait to hear the first results.

Posted: 5/9/2008 5:31:01 PM
djpb_designs

From: Escondido, CA

Joined: 2/6/2008

I would hazard a guess that a cellphone creates a lot more radiation than any theremin ever made!

The original pacemaker vs. RF source caution was with regards to microwave ovens with leaky seals as I remember. There was a period of time where you would see signs warning: "Caution microwave oven in use".

You don't see those around here anymore.

Don

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