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Author Topic: Can A Noise Be Turned Into Electrical Energy ?  (Read 7330 times)

Offline neilep

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Can A Noise Be Turned Into Electrical Energy ?
« on: 02/10/2007 13:39:49 »
Dear Sound Engineers,

My daughter just asked me if it's possible to convert sound waves into energy ?...well..i don't know !!

But doesn't a sound get converted when you speak into a microphone ?...could that be stored as energy in a battery ?....it's electrical impulses isn't it ?
...it could make loud places fuel efficient !!...after all noises break things don't they ?...so..that must mean they are a source of energy !!

whajafink ?


 

Offline Karen W.

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Can A Noise Be Turned Into Electrical Energy ?
« Reply #1 on: 02/10/2007 16:08:40 »
Sounds good to me.. how do we store our jabberbox energy though! How would we capture our gift of gab and store it in cells or batteries!
 

Offline syhprum

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Can A Noise Be Turned Into Electrical Energy ?
« Reply #2 on: 02/10/2007 16:43:53 »
Loudspeakers are very inefficient devices for turning electrical energy into sound only 2 or 3% so if we use them as moving coil microphones presumably we get very little out.
The only application of converting sound energy into power was in some clocks that were powered by variation in atmospheric pressure which of course is a very low frequency sound wave but the power was only in the region of microwatts.
 

another_someone

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Can A Noise Be Turned Into Electrical Energy ?
« Reply #3 on: 02/10/2007 17:46:45 »
I suppose you could convert the power of an earthquake into a reasonable amount of energy (earthquakes are themselves sound waves).

There is not a lot of energy to be had in ordinary atmospheric sound (if you had megawatts of energy in the sound, you would blow your ears out, and probably destroy much of your internal organs).

http://www.sengpielaudio.com/TableOfSoundPressureLevels.htm
Quote
Table of sound levels L and corresponding
sound pressure and sound intensity
ExamplesSound Pressure
Level Lp dBSPL
Sound Pressure p N/m2 = PaSound Intensity I
W/m2
Jet aircraft, 50 m away140200100
Threshold of pain13063.210
Threshold of discomfort120201
Chainsaw, 1m distance1106.30.1
Disco, 1 m from speaker10020.01
Diesel truck, 10 m away900.630.001
Kerbside of busy road, 5 m800.20.0001
Vacuum cleaner, distance 1 m700.0630.00001
Conversational speech, 1m600.020.000001
Average home500.00630.0000001
Quiet library400.0020.00000001
Quiet bedroom at night300.000630.000000001
Background in TV studio200.00020.0000000001
Rustling leaf100.0000630.00000000001
Threshold of hearing00.000020.000000000001

Loudspeakers have various design criteria, and linear frequency and phase response is generally more important than energy efficiency.  No doubt one could improve the energy efficiency if one throws acoustic fidelity out of the window.

Nonetheless, even if one had a 100% efficient conversion of sound energy, you would need t look at structures several square metres across, situated in an airport, in order to begin to capture appreciable amounts of energy (even in the kilowatt region).
 

Offline eric l

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Can A Noise Be Turned Into Electrical Energy ?
« Reply #4 on: 02/10/2007 18:25:24 »
I think that sound detecting system that was used in the days of the Battle of Brittain, as an alternative to the primitive radar, was in a way an application.  It needed large parabolic sound mirrors. 
But I have a problem finding documentation on it.
 

Offline syhprum

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Can A Noise Be Turned Into Electrical Energy ?
« Reply #5 on: 02/10/2007 20:08:15 »
 

Offline eric l

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Can A Noise Be Turned Into Electrical Energy ?
« Reply #6 on: 02/10/2007 20:14:14 »
Take a look here

http://www.ajg41.clara.co.uk/mirrors/
Thank you !  Never thought they were as old as that !  WW1, that means they must have been built to hear the zeppelins approaching (as well as airplanes).
 

lyner

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Can A Noise Be Turned Into Electrical Energy ?
« Reply #7 on: 03/10/2007 13:26:55 »
Sound as an energy resource: think about it this way.
A transistor radio may use 1W of electrical power - producing , say 50mW of sound power. If you stand within a metre or so, even that will sound quite loud. If you gathered all of that sound energy - not just the bit getting into your ears- you could only get 50mW.
A loudspeaker  system in a club might produce 1000 times that level (your poor ears). But that would only get you 50W of energy to play with.
The only mechanical waves around that are worth tapping into are Sea waves. Now that's another story.
 

another_someone

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Can A Noise Be Turned Into Electrical Energy ?
« Reply #8 on: 03/10/2007 13:32:38 »
A loudspeaker  system in a club might produce 1000 times that level (your poor ears). But that would only get you 50W of energy to play with.

Actually, I rather suspect you would get more energy from the foot impact of the dancers (piezo-electric carpets?).
 

Offline neilep

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Can A Noise Be Turned Into Electrical Energy ?
« Reply #9 on: 03/10/2007 16:39:11 »
THANK YOU THANK YOU ALL for a fascinating thread !

Thanks for the mirrors link Syhprum, and thank you for the graph George
« Last Edit: 03/10/2007 16:42:11 by neilep »
 

Offline neilep

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Can A Noise Be Turned Into Electrical Energy ?
« Reply #10 on: 03/10/2007 16:44:13 »
so, really, using sound as an energy resource is ineffective !

Good..I'll pass this info onto wifey.....perhaps it'll shut her up for once !!.. ;)
 

Offline Karen W.

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Can A Noise Be Turned Into Electrical Energy ?
« Reply #11 on: 03/10/2007 16:46:57 »
Loudspeakers are very inefficient devices for turning electrical energy into sound only 2 or 3% so if we use them as moving coil microphones presumably we get very little out.
The only application of converting sound energy into power was in some clocks that were powered by variation in atmospheric pressure which of course is a very low frequency sound wave but the power was only in the region of microwatts.

That is interesting..sorry  I understand this is a unit of measure in electrical lingo, but exactly what is a microwatt, I have never heard the term. Is it conducive of its name meaning a tiny piece of wattage?? Sorry?
 

Offline Karen W.

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Can A Noise Be Turned Into Electrical Energy ?
« Reply #12 on: 03/10/2007 16:50:41 »
George what are (piezo-electric carpets?).
 

Offline eric l

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Can A Noise Be Turned Into Electrical Energy ?
« Reply #13 on: 03/10/2007 18:12:54 »
"Piezo-electric" means that pressure is converted into electricity.
In practice, pressure difference (over time) create differences in tension.
The old pick ups (you know, from the days of viny records) had either piezo-electric or magneto-dynamic cells. 
With those piezo-electric cells, the needle's tip touched the record at the bottom of the track, while the top of the needle touched a crystal.  This crystal was piezo-electric, which means that pressure differences due to the unevenness engraved in the track created a kind of alternating tension as the needle went through the track, and this alternating tension could be amplified and converted into sound by the loudspeakers.
 

Offline Karen W.

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Can A Noise Be Turned Into Electrical Energy ?
« Reply #14 on: 03/10/2007 18:20:07 »
Pick ups = turn tables or the record players arms??

The explanation is good thank you I understand better now!
 

Offline syhprum

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Can A Noise Be Turned Into Electrical Energy ?
« Reply #15 on: 03/10/2007 19:46:14 »
Karen I am amazed that you are not familiar with the prefix micro, it simply means that you multiply the following unit by 10^-6 (are you having me on!)
 

Offline Karen W.

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Can A Noise Be Turned Into Electrical Energy ?
« Reply #16 on: 03/10/2007 19:59:19 »
Micro to me means tiny, by how much I haven't a clue, and when you use


math I have even less of a clue! LOL! Sorry Thats what I am here for to

learn more! LOL I was never a good science student and took an interest

as an adult learning to teach very young children about science.. LOL Most of it is

over my head even as an adult and I am in no way embarrassed by it!

It is a fact I hated science as a kid and would have done most anything

to avoid it. I had horrible science teachers who were so dry in their

presentation that they took no fun in doing any hands on experiments to

teach relatively easy theories for YOU.. not so easy for me.

Now the term micro to me I guess I could have looked up but know it

normally refers to something tiny in size.. NO...NOT JOKING, sorry I

can't even read your equation~! LOL

I read wiki's meaning and basically what I knew was this:

MICRO is an English prefix of Greek origin that refers to an object as being smaller

than an object or scale of focus, in contrast with macro.

I did not ever know the rest! LOL And still would not be able to do the math.. LOL 

what does the upside down v tell you to do?
« Last Edit: 04/10/2007 05:52:52 by Karen W. »
 

another_someone

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Can A Noise Be Turned Into Electrical Energy ?
« Reply #17 on: 03/10/2007 21:05:29 »
Micro is generically used to mean very small, but the precise meaning for SI units of measure is one millionth, so a microwatt is one millionth of a watt.

The upside down 'V' (technically a caret) is a symbol used by some computer languages to mean to the power of (what here is shown as 10^-6, in other computer languages would be shown as 10**-6, but in conventional mathematical nomenclature would be 10-6).
 

Offline syhprum

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« Reply #18 on: 03/10/2007 21:32:03 »
Why I use 10^-6  is because to write a high small 6 is beyond my typographical skills, I can manage 10‾6 but not the high 6 even If I try to use 'cut and paste' it does not come out right
 

another_someone

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Can A Noise Be Turned Into Electrical Energy ?
« Reply #19 on: 03/10/2007 21:42:36 »
Why I use 10^-6  is because to write a high small 6 is beyond my typographical skills, I can manage 10‾6 but not the high 6 even If I try to use 'cut and paste' it does not come out right
Use 10[sup]-6[/sup]

Suggest you read http://www.thenakedscientists.com/forum/index.php?action=help;page=post#bbcref
 

Offline syhprum

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« Reply #20 on: 03/10/2007 21:52:43 »
10-6 Thanks, it seems to work!
 

Offline Karen W.

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Can A Noise Be Turned Into Electrical Energy ?
« Reply #21 on: 04/10/2007 05:57:02 »
Why I use 10^-6  is because to write a high small 6 is beyond my typographical skills, I can manage 10‾6 but not the high 6 even If I try to use 'cut and paste' it does not come out right
Use 10[sup]-6[/sup]

Suggest you read http://www.thenakedscientists.com/forum/index.php?action=help;page=post#bbcref

I DID NOT KNOW ABOUT THAT PAGE GEORGE!
 

Offline Karen W.

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« Reply #22 on: 04/10/2007 05:59:15 »
IS 10 TO THE 6TH POWER 60.. OR AM I STILL NOT REMEMBERING MY MATH VERY WELL?
 

Offline syhprum

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« Reply #23 on: 04/10/2007 07:23:31 »
Karen

Ten to the power of 6 means 10 multiplied by its self 6 times i.e 1,000,000

if the power is negative it means that you raise it to the sixth power making 1,000,000 then take the inverse making the result being 0.000001

If you had been educated in pre calculator times and had to work with logarithms you would be familiar with these concepts
 

Offline Karen W.

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« Reply #24 on: 04/10/2007 10:19:35 »
Syhphram I hated math! LOL Decided to go back to college as an adult at 41 years old only a couple classes at a time I have basically completed all but 1 class in all my Early child development and need to do all my general ed. I have run into health complications and cannot continue at this point. That doesn't mean I am against learning though ..LOL

I seemed to have remembered multiplying, but I was multiplying 10x6 not 10 x itself. Thanks for the explanation. we were never allowed a calculator in school or at home. I am not a youngster, just not any good at all in math! LOL I know where my weaknesses are and there are many!
« Last Edit: 04/10/2007 18:18:28 by Karen W. »
 

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Can A Noise Be Turned Into Electrical Energy ?
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