Demodulating a laser beam
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Posts: 46,084
Anyone try to shoot a laser beam at a window, have it
reflected, and demodulate it to get audio?
Art
reflected, and demodulate it to get audio?
Art
Comments
Original Message
From: "Art Burke" <pianomanab@s...>
To: <basicstamps@yahoogroups.com>
Sent: Monday, February 04, 2002 3:50 PM
Subject: [noparse][[/noparse]basicstamps] Demodulating a laser beam
> Anyone try to shoot a laser beam at a window, have it
> reflected, and demodulate it to get audio?
>
> Art
>
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>
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->
Original Message
->From: Stephen H Chapman [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=4r6xt_fuKIwqQ9TAos69e_Fg_GCNctTcKz_nXNVXquNA8Y6qCM49aLUz9VnBnaON5aVp6Y-xo_UV_Q]chapman@t...[/url
->Sent: Monday, February 04, 2002 7:08 PM
->To: basicstamps@yahoogroups.com
->Subject: Re: [noparse][[/noparse]basicstamps] Demodulating a laser beam
->
->
->Yes it works. No I will not tell you how to do it.
->
Original Message
->From: "Art Burke" <pianomanab@s...>
->To: <basicstamps@yahoogroups.com>
->Sent: Monday, February 04, 2002 3:50 PM
->Subject: [noparse][[/noparse]basicstamps] Demodulating a laser beam
->
->
->> Anyone try to shoot a laser beam at a window, have it
->> reflected, and demodulate it to get audio?
->>
->> Art
->>
->> To UNSUBSCRIBE, just send mail to:
->> basicstamps-unsubscribe@yahoogroups.com
->> from the same email address that you subscribed. Text in the
->Subject and
->Body of the message will be ignored.
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->http://docs.yahoo.com/info/terms/
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->>
->
->
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-> basicstamps-unsubscribe@yahoogroups.com
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->Subject and Body of the message will be ignored.
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you can buy plans, kits and assembled kits from:
http://www.amazing1.com
and lots of other silly and wierd things.
Original Message
From: "Art Burke" <pianomanab@s...>
To: <basicstamps@yahoogroups.com>
Sent: Monday, February 04, 2002 7:31 PM
Subject: RE: [noparse][[/noparse]basicstamps] Demodulating a laser beam
> I didn't ask you how.....
>
>
> ->
Original Message
> ->From: Stephen H Chapman [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=5LMCXgXkdCrG9NCepsOeXhFWU8cuQFJqYnaPTGU6T8mV7AddtavqZpwKbE56Dqbxx_VCjIoixg]chapman@t...[/url
> ->Sent: Monday, February 04, 2002 7:08 PM
> ->To: basicstamps@yahoogroups.com
> ->Subject: Re: [noparse][[/noparse]basicstamps] Demodulating a laser beam
> ->
> ->
> ->Yes it works. No I will not tell you how to do it.
> ->
Original Message
> ->From: "Art Burke" <pianomanab@s...>
> ->To: <basicstamps@yahoogroups.com>
> ->Sent: Monday, February 04, 2002 3:50 PM
> ->Subject: [noparse][[/noparse]basicstamps] Demodulating a laser beam
> ->
> ->
> ->> Anyone try to shoot a laser beam at a window, have it
> ->> reflected, and demodulate it to get audio?
> ->>
> ->> Art
> ->>
> ->> To UNSUBSCRIBE, just send mail to:
> ->> basicstamps-unsubscribe@yahoogroups.com
> ->> from the same email address that you subscribed. Text in the
> ->Subject and
> ->Body of the message will be ignored.
> ->>
> ->>
> ->> Your use of Yahoo! Groups is subject to
> ->http://docs.yahoo.com/info/terms/
> ->>
> ->>
> ->>
> ->
> ->
> ->To UNSUBSCRIBE, just send mail to:
> -> basicstamps-unsubscribe@yahoogroups.com
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http://docs.yahoo.com/info/terms/
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> ->
> ->
>
>
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I have a book Optoelectronics, Fiber Optics, and Laser Cookbook
by Thomas Petruzzellis it has this very project in it.
looks like no big deal
Original Message
From: "Art Burke" <pianomanab@s...>
To: <basicstamps@yahoogroups.com>
Sent: February 04, 2002 3:50 PM
Subject: [noparse][[/noparse]basicstamps] Demodulating a laser beam
Anyone try to shoot a laser beam at a window, have it
reflected, and demodulate it to get audio?
Art
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on this project.
Bruce
Larry Gaminde wrote:
> Art
> I have a book Optoelectronics, Fiber Optics, and Laser Cookbook
> by Thomas Petruzzellis it has this very project in it.
> looks like no big deal
>
Original Message
> From: "Art Burke" <pianomanab@s...>
> To: <basicstamps@yahoogroups.com>
> Sent: February 04, 2002 3:50 PM
> Subject: [noparse][[/noparse]basicstamps] Demodulating a laser beam
>
> Anyone try to shoot a laser beam at a window, have it
> reflected, and demodulate it to get audio?
>
> Art
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the
> Subject and Body of the message will be ignored.
>
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> http://docs.yahoo.com/info/terms/
>
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> Art
> I have a book Optoelectronics, Fiber Optics, and Laser Cookbook
> by Thomas Petruzzellis it has this very project in it.
> looks like no big deal
Any chance of getting the ISBN # for this book ?
Thanks !
--
Dale Harwood [noparse][[/noparse] N4VFF ]
internet> dale@h...
ax.25> n4vff@n4vff.#cha.tn.usa.noam
#include <std_disclaimer.h>
kidding
its 0-07-049840-7 this number on top ISBN to left
barcode goes here
or 9 780070 498402 This may be the barcode number
Original Message
From: "Dale Harwood" <dale@h...>
To: <basicstamps@yahoogroups.com>
Sent: February 04, 2002 6:23 PM
Subject: Re: [noparse][[/noparse]basicstamps] Demodulating a laser beam
On Mon, 4 Feb 2002, Larry Gaminde wrote:
> Art
> I have a book Optoelectronics, Fiber Optics, and Laser Cookbook
> by Thomas Petruzzellis it has this very project in it.
> looks like no big deal
Any chance of getting the ISBN # for this book ?
Thanks !
--
Dale Harwood [noparse][[/noparse] N4VFF ]
internet> dale@h...
ax.25> n4vff@n4vff.#cha.tn.usa.noam
#include <std_disclaimer.h>
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The Laser Cookbook: 88 Practical Projects
Paperback - 304 pages 1 edition (October 1, 1988)
McGraw-Hill; ISBN: 0071553355
Amazon link:
http://www.amazon.com/exec/obidos/ASIN/0830693904/ref=ase_starwarsportal/102
-0195948-7736137
Original Message
From: Dale Harwood [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=-_-5ttmdME2Fo-E18rqf7ji7ByP4s_CT95_CKx6YaJueGDtbbcQTeehqztkMq3IxS3KxzCLnT_Lh]dale@h...[/url
Sent: Monday, February 04, 2002 9:24 PM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] Demodulating a laser beam
On Mon, 4 Feb 2002, Larry Gaminde wrote:
> Art
> I have a book Optoelectronics, Fiber Optics, and Laser Cookbook
> by Thomas Petruzzellis it has this very project in it.
> looks like no big deal
Any chance of getting the ISBN # for this book ?
Thanks !
--
Dale Harwood [noparse][[/noparse] N4VFF ]
internet> dale@h...
ax.25> n4vff@n4vff.#cha.tn.usa.noam
#include <std_disclaimer.h>
To UNSUBSCRIBE, just send mail to:
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> reflected, and demodulate it to get audio?
>
The ARRL (American Radio Relay League) Handbook has dealt with laser
modulation for communications. Most of that would be applicable. There was
a Radio Electronics Article in teh late 80's that had a complete article on
doing just that.
Mark Hillier, VE6HVW
President, HVW Technologies Inc.
Canadian Distributors of Parallax Products and other Neat Stuff
Tel: (403)-730-8603 Fax: (403)-730-8903
See our NEW FPGA Experimenter Board
http://www.hvwtech.com/intro-fpga.htm
Original Message
From: "Mark Hillier" <Mark@H...>
To: <basicstamps@yahoogroups.com>
Sent: Tuesday, February 05, 2002 11:04 AM
Subject: Re: [noparse][[/noparse]basicstamps] Demodulating a laser beam
>
>
> > Anyone try to shoot a laser beam at a window, have it
> > reflected, and demodulate it to get audio?
> >
>
> The ARRL (American Radio Relay League) Handbook has dealt with laser
> modulation for communications. Most of that would be applicable. There was
> a Radio Electronics Article in teh late 80's that had a complete article
on
> doing just that.
>
>
> Mark Hillier, VE6HVW
> President, HVW Technologies Inc.
> Canadian Distributors of Parallax Products and other Neat Stuff
> Tel: (403)-730-8603 Fax: (403)-730-8903
> See our NEW FPGA Experimenter Board
> http://www.hvwtech.com/intro-fpga.htm
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
where some one is talking. Then look at the reflected beam with a
telescope or binoculars and feed this light output to a photo cell
sensitive to the frequency of the laser, to a low amplitude amplifier.
Amplify the signal enough and you might say, "wow there's people in
there".
regards,
leroy
<SNIP>
several advertisements for such a device along with a rather terse
warning that using it to listen in on conversations in a room was
illegal and subject to prosecution.
--- In basicstamps@y..., Leroy Hall <leroy@f...> wrote:
> I suspect the general procedure is to shine a laser beam on a window
> where some one is talking. Then look at the reflected beam with a
> telescope or binoculars and feed this light output to a photo cell
> sensitive to the frequency of the laser, to a low amplitude
amplifier.
> Amplify the signal enough and you might say, "wow there's people in
> there".
>
>
> regards,
>
> leroy
>
> <SNIP>
beam with a sample of the transmitter beam. The reflected beam would be
phase modulated with respect to the transmitted beam.
John
--
John Fletcher
say about operations of a laser
modulation.
"The sound waves generated by nearby conversations will cause the glass in a
window to vibrate very slightly. If
a laser beam is bounced off the window, its reflection will be modulated by the
vibrations. All that's needed to
hear what is being said is a demodulating device that extracts the audio from
the reflected laser beam. " ( a
phototransister driving a audio amplifier)
They do show using the device with a rifle scope.
An interesting side note, the article indicates that using the device is not
illegal. BUT that was 1987 !
Present day law states that using a electronic device to intercept private
conversation is ILLEGAL. This would
be fun to play with, just don't use it to monitor the mating habits of your
neighbor. Even having to explain
aiming a rife scope at someone's house would be bad.
This article appeared just a few years after the US Embassy in Moscow accused
the Russians of using lasers to
eavesdrop back in the cold war.
Bruce
John Fletcher wrote:
> I haven't tried it but I would guess that you have to mix the reflected
> beam with a sample of the transmitter beam. The reflected beam would be
> phase modulated with respect to the transmitted beam.
>
> John
> --
> John Fletcher
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and Body
of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
I don't need no stinking laser to here them!!
Original Message
From: "Bruce" <bsnowde@a...>
To: <basicstamps@yahoogroups.com>
Sent: February 07, 2002 1:15 PM
Subject: Re: [noparse][[/noparse]basicstamps] Re: Demodulating a laser beam
I dug out my copy of Radio-Electronics dated October 1987. To
quote what they say about operations of a laser
modulation.
"The sound waves generated by nearby conversations will cause the
glass in a window to vibrate very slightly. If
a laser beam is bounced off the window, its reflection will be
modulated by the vibrations. All that's needed to
hear what is being said is a demodulating device that extracts
the audio from the reflected laser beam. " ( a
phototransister driving a audio amplifier)
They do show using the device with a rifle scope.
An interesting side note, the article indicates that using the
device is not illegal. BUT that was 1987 !
Present day law states that using a electronic device to
intercept private conversation is ILLEGAL. This would
be fun to play with, just don't use it to monitor the mating
habits of your neighbor. Even having to explain
aiming a rife scope at someone's house would be bad.
This article appeared just a few years after the US Embassy in
Moscow accused the Russians of using lasers to
eavesdrop back in the cold war.
Bruce
John Fletcher wrote:
> I haven't tried it but I would guess that you have to mix the
reflected
> beam with a sample of the transmitter beam. The reflected beam
would be
> phase modulated with respect to the transmitted beam.
>
> John
> --
> John Fletcher
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the
Subject and Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/
To UNSUBSCRIBE, just send mail to:
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only if the rifle is still attached, and they can see the red
dot!
Original Message
From: "Bruce" <bsnowde@a...>
To: <basicstamps@yahoogroups.com>
Sent: February 07, 2002 1:15 PM
Subject: Re: [noparse][[/noparse]basicstamps] Re: Demodulating a laser beam
I dug out my copy of Radio-Electronics dated October 1987. To
quote what they say about operations of a laser
modulation.
"The sound waves generated by nearby conversations will cause the
glass in a window to vibrate very slightly. If
a laser beam is bounced off the window, its reflection will be
modulated by the vibrations. All that's needed to
hear what is being said is a demodulating device that extracts
the audio from the reflected laser beam. " ( a
phototransister driving a audio amplifier)
They do show using the device with a rifle scope.
An interesting side note, the article indicates that using the
device is not illegal. BUT that was 1987 !
Present day law states that using a electronic device to
intercept private conversation is ILLEGAL. This would
be fun to play with, just don't use it to monitor the mating
habits of your neighbor. Even having to explain
aiming a rife scope at someone's house would be bad.
This article appeared just a few years after the US Embassy in
Moscow accused the Russians of using lasers to
eavesdrop back in the cold war.
Bruce
John Fletcher wrote:
> I haven't tried it but I would guess that you have to mix the
reflected
> beam with a sample of the transmitter beam. The reflected beam
would be
> phase modulated with respect to the transmitted beam.
>
> John
> --
> John Fletcher
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the
Subject and Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/
To UNSUBSCRIBE, just send mail to:
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such a device. Having said that, there are both State Specific and Federal laws
which apply to using any surveillance type equipment in general. There are
certain specific circumstances that allow for the interception of private
conversations. One circumstance might include the monitoring of an individual
who has physically threatened your life, you had better be able to prove it, and
you better check the laws in your area first.
Larry Gaminde <lgaminde@t...> wrote: aiming a rife scope at someone's
house would be bad
only if the rifle is still attached, and they can see the red
dot!
Original Message
From: "Bruce"
To:
Sent: February 07, 2002 1:15 PM
Subject: Re: [noparse][[/noparse]basicstamps] Re: Demodulating a laser beam
I dug out my copy of Radio-Electronics dated October 1987. To
quote what they say about operations of a laser
modulation.
"The sound waves generated by nearby conversations will cause the
glass in a window to vibrate very slightly. If
a laser beam is bounced off the window, its reflection will be
modulated by the vibrations. All that's needed to
hear what is being said is a demodulating device that extracts
the audio from the reflected laser beam. " ( a
phototransister driving a audio amplifier)
They do show using the device with a rifle scope.
An interesting side note, the article indicates that using the
device is not illegal. BUT that was 1987 !
Present day law states that using a electronic device to
intercept private conversation is ILLEGAL. This would
be fun to play with, just don't use it to monitor the mating
habits of your neighbor. Even having to explain
aiming a rife scope at someone's house would be bad.
This article appeared just a few years after the US Embassy in
Moscow accused the Russians of using lasers to
eavesdrop back in the cold war.
Bruce
John Fletcher wrote:
> I haven't tried it but I would guess that you have to mix the
reflected
> beam with a sample of the transmitter beam. The reflected beam
would be
> phase modulated with respect to the transmitted beam.
>
> John
> --
> John Fletcher
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the
Subject and Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/
To UNSUBSCRIBE, just send mail to:
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Do You Yahoo!?
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[noparse][[/noparse]Non-text portions of this message have been removed]
someone listening to my conversations, not that they would want to
<GRIN>. Just like the gun laws, only crooks carry guns, but of course
that's OK because they are crooks anyway.
Troy S wrote:
>
> I would hope that the moral issues should make someone think twice about using
such a device. Having said that, there are both State Specific and Federal laws
which apply to using any surveillance type equipment in general. There are
certain specific circumstances that allow for the interception of private
conversations. One circumstance might include the monitoring of an individual
who has physically threatened your life, you had better be able to prove it, and
you better check the laws in your area first.
>
> Larry Gaminde <lgaminde@t...> wrote: aiming a rife scope at someone's
house would be bad
>
> only if the rifle is still attached, and they can see the red
> dot!
>
>
Original Message
> From: "Bruce"
> To:
> Sent: February 07, 2002 1:15 PM
> Subject: Re: [noparse][[/noparse]basicstamps] Re: Demodulating a laser beam
>
> I dug out my copy of Radio-Electronics dated October 1987. To
> quote what they say about operations of a laser
> modulation.
>
> "The sound waves generated by nearby conversations will cause the
> glass in a window to vibrate very slightly. If
> a laser beam is bounced off the window, its reflection will be
> modulated by the vibrations. All that's needed to
> hear what is being said is a demodulating device that extracts
> the audio from the reflected laser beam. " ( a
> phototransister driving a audio amplifier)
>
> They do show using the device with a rifle scope.
>
> An interesting side note, the article indicates that using the
> device is not illegal. BUT that was 1987 !
> Present day law states that using a electronic device to
> intercept private conversation is ILLEGAL. This would
> be fun to play with, just don't use it to monitor the mating
> habits of your neighbor. Even having to explain
> aiming a rife scope at someone's house would be bad.
>
> This article appeared just a few years after the US Embassy in
> Moscow accused the Russians of using lasers to
> eavesdrop back in the cold war.
>
> Bruce
>
> John Fletcher wrote:
>
> > I haven't tried it but I would guess that you have to mix the
> reflected
> > beam with a sample of the transmitter beam. The reflected beam
> would be
> > phase modulated with respect to the transmitted beam.
> >
> > John
> > --
> > John Fletcher
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@yahoogroups.com
> > from the same email address that you subscribed. Text in the
> Subject and Body of the message will be ignored.
> >
> >
> > Your use of Yahoo! Groups is subject to
> http://docs.yahoo.com/info/terms/
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
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>
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>
>
> Do You Yahoo!?
> Send FREE Valentine eCards with Yahoo! Greetings!
>
> [noparse][[/noparse]Non-text portions of this message have been removed]
>
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