Is there such a thing as an acoustic array/matrix ?
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Posts: 46,084
I was looking over the CMUcamera example, about how it
divides everything into a grid, so it can track the
color blob
Well, can you do this with sound? In a compact way, I don't
want some big honkin thing, just a little-ish device.
I want to build something that can zero in on birds.
And then of course, either take their picture, or
eviscerate them with a laser. -just kidding
divides everything into a grid, so it can track the
color blob
Well, can you do this with sound? In a compact way, I don't
want some big honkin thing, just a little-ish device.
I want to build something that can zero in on birds.
And then of course, either take their picture, or
eviscerate them with a laser. -just kidding
Comments
and N is determined by environmental factors and mike
sensitivity/slectivity. On open prairie or water, 2 mikes or 2 human
ears (with normal hearing) would do the task. Ask any duck hunter. [noparse]:)[/noparse]
Dennis
Original Message
From: rdenn25 [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=CDsISYSq3BjC2hHrUVgs9XVtbcHvsXSCnsEkDyo9cKsZz1yd6P2N9BqlmgBpJqmQMkVtJw]rad0@a...[/url
Sent: Friday, June 20, 2003 5:02 PM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] Is there such a thing as an acoustic array/matrix
?
I was looking over the CMUcamera example, about how it
divides everything into a grid, so it can track the
color blob
Well, can you do this with sound? In a compact way, I don't want some
big honkin thing, just a little-ish device.
I want to build something that can zero in on birds.
And then of course, either take their picture, or
eviscerate them with a laser. -just kidding
To UNSUBSCRIBE, just send mail to:
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wrote:
> This would require an array of N directional microphones, where N
> 1,
> and N is determined by environmental factors and mike
> sensitivity/slectivity. On open prairie or water, 2 mikes or 2
human
> ears (with normal hearing) would do the task. Ask any duck
hunter. [noparse]:)[/noparse]
>
> Dennis
>
bear with me. are you saying that I could make an
acoustic 'pointer/tracker' with two or three microphone?
are there any examples of this thing for stamps or microcontrollers?
thanks
Graf Pen) from the early 1980s. The pen contained a spark source that
emitted a sharp audible click when a button was pressed, or at a known
rate in a "free run" mode. The detectors were bar microphones
surrounding the digitizing area, oriented in either an X-Y, or X-Y-Z
configuration. Tracking of the stylus pointer was based on acoustic
delay to the microphone detectors. The 2-dim system is about 36" x 36",
and the 3 dim system is about 12" cubed.
It could be done accurately with a fast microcontroller, running at 20
MHz or more. The expensive part is probably the microphones.
Dennis
Original Message
From: rdenn25 [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=yZ25wh9mCoVAopHW0u6ATdxO2wpBH45Irj5skIdFFscQ8jztVq-w2iuxxSXsXhsoldEfRsw]rad0@a...[/url
Sent: Friday, June 20, 2003 7:56 PM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] Re: Is there such a thing as an acoustic
array/matrix ?
--- In basicstamps@yahoogroups.com, Dennis O'Leary <doleary@e...>
wrote:
> This would require an array of N directional microphones, where N
> 1,
> and N is determined by environmental factors and mike
> sensitivity/slectivity. On open prairie or water, 2 mikes or 2
human
> ears (with normal hearing) would do the task. Ask any duck
hunter. [noparse]:)[/noparse]
>
> Dennis
>
bear with me. are you saying that I could make an
acoustic 'pointer/tracker' with two or three microphone?
are there any examples of this thing for stamps or microcontrollers?
thanks
To UNSUBSCRIBE, just send mail to:
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>I was looking over the CMUcamera example, about how it
>divides everything into a grid, so it can track the
>color blob
>
>Well, can you do this with sound? In a compact way, I don't
>want some big honkin thing, just a little-ish device.
>
>I want to build something that can zero in on birds.
>And then of course, either take their picture, or
>eviscerate them with a laser. -just kidding
You can do this sort of thing with triangulation by measuring
the intensity of three directional microphones arranged 120
degrees facing away from center. I did this as a kid with
thunder and lightning to pinpoint direction as well as distance
of a strike.
-Beau Schwabe
(difference in arrival times) at each microphone, then
swing the two microphones to zero out the phase
difference -- or use the phase difference to get
a direction to the source. I'm not sure this
is a task for the BS2, since in a 'noisy'
environment determining the identity of a single
sound, to find the start time of it,
could be difficult.
Human hearing is VERY good at differentiating
sounds, and using the phase difference to
determine a direction to the sound. That
doesn't mean it's easy for a CPU.
The CMU-Cam has an on-board processor which
processes the pixels for you, to determine
locations and movement for you.
--- In basicstamps@yahoogroups.com, "rdenn25" <rad0@a...> wrote:
> --- In basicstamps@yahoogroups.com, Dennis O'Leary <doleary@e...>
> wrote:
> > This would require an array of N directional microphones, where N
> > 1,
> > and N is determined by environmental factors and mike
> > sensitivity/slectivity. On open prairie or water, 2 mikes or 2
> human
> > ears (with normal hearing) would do the task. Ask any duck
> hunter. [noparse]:)[/noparse]
> >
> > Dennis
> >
>
> bear with me. are you saying that I could make an
> acoustic 'pointer/tracker' with two or three microphone?
>
> are there any examples of this thing for stamps or microcontrollers?
> thanks
instead of a microphone, to hook to the stamp,
it would take an 'ear' to go to the stamp
this doesn't exist, does it...
thanks for the explanation
Original Message
From: "Allan Lane" <allan.lane@h...>
To: <basicstamps@yahoogroups.com>
Sent: Monday, June 23, 2003 4:07 PM
Subject: [noparse][[/noparse]basicstamps] Re: Is there such a thing as an acoustic array/matrix
?
> The goal here would be to measure the phase difference
> (difference in arrival times) at each microphone, then
> swing the two microphones to zero out the phase
> difference -- or use the phase difference to get
> a direction to the source. I'm not sure this
> is a task for the BS2, since in a 'noisy'
> environment determining the identity of a single
> sound, to find the start time of it,
> could be difficult.
>
> Human hearing is VERY good at differentiating
> sounds, and using the phase difference to
> determine a direction to the sound. That
> doesn't mean it's easy for a CPU.
>
> The CMU-Cam has an on-board processor which
> processes the pixels for you, to determine
> locations and movement for you.
>
>
> --- In basicstamps@yahoogroups.com, "rdenn25" <rad0@a...> wrote:
> > --- In basicstamps@yahoogroups.com, Dennis O'Leary <doleary@e...>
> > wrote:
> > > This would require an array of N directional microphones, where N
> > > 1,
> > > and N is determined by environmental factors and mike
> > > sensitivity/slectivity. On open prairie or water, 2 mikes or 2
> > human
> > > ears (with normal hearing) would do the task. Ask any duck
> > hunter. [noparse]:)[/noparse]
> > >
> > > Dennis
> > >
> >
> > bear with me. are you saying that I could make an
> > acoustic 'pointer/tracker' with two or three microphone?
> >
> > are there any examples of this thing for stamps or microcontrollers?
> > thanks
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
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>
>
acoustic sonar array
acoustic sensor array
phased array microphone.
For example:
http://www.jamminpower.com/PDF/Phased-Array%20Microphone.htm
These things exist . They are used for sonar detection and for acoustic lab
work, such as automobile noise analysis.
rad0 <rad0@a...> wrote:
Yeah OK, I see what you are saying
instead of a microphone, to hook to the stamp,
it would take an 'ear' to go to the stamp
this doesn't exist, does it...
thanks for the explanation
Original Message
From: "Allan Lane"
To:
Sent: Monday, June 23, 2003 4:07 PM
Subject: [noparse][[/noparse]basicstamps] Re: Is there such a thing as an acoustic array/matrix
?
> The goal here would be to measure the phase difference
> (difference in arrival times) at each microphone, then
> swing the two microphones to zero out the phase
> difference -- or use the phase difference to get
> a direction to the source. I'm not sure this
> is a task for the BS2, since in a 'noisy'
> environment determining the identity of a single
> sound, to find the start time of it,
> could be difficult.
>
> Human hearing is VERY good at differentiating
> sounds, and using the phase difference to
> determine a direction to the sound. That
> doesn't mean it's easy for a CPU.
>
> The CMU-Cam has an on-board processor which
> processes the pixels for you, to determine
> locations and movement for you.
>
>
> --- In basicstamps@yahoogroups.com, "rdenn25" wrote:
> > --- In basicstamps@yahoogroups.com, Dennis O'Leary
> > wrote:
> > > This would require an array of N directional microphones, where N
> > > 1,
> > > and N is determined by environmental factors and mike
> > > sensitivity/slectivity. On open prairie or water, 2 mikes or 2
> > human
> > > ears (with normal hearing) would do the task. Ask any duck
> > hunter. [noparse]:)[/noparse]
> > >
> > > Dennis
> > >
> >
> > bear with me. are you saying that I could make an
> > acoustic 'pointer/tracker' with two or three microphone?
> >
> > are there any examples of this thing for stamps or microcontrollers?
> > thanks
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
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[noparse][[/noparse]Non-text portions of this message have been removed]
you need at least 2 "receivers" (ears, microphones, or whatever), plus
some electronic processing method of detecting small time differences in
when the sound arrives at each receiver. Also, note that the
"processor" must know the location of each of the receivers, and then
solve some trigonometric equations to localize the sound source. Sounds
simple, but solving trig equations is not what the Stamp is good at.
Dennis
Original Message
From: rad0 [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=4iHAiQl_FJaOmKBd4X1v7khUC9OY5XdaikUuYQMSz3JIGq8tnHjpSx7M9q0Fk7WFNkE4pDpdgGDd]rad0@a...[/url
Sent: Monday, June 23, 2003 2:50 PM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] Re: Is there such a thing as an acoustic
array/matrix ?
Yeah OK, I see what you are saying
instead of a microphone, to hook to the stamp,
it would take an 'ear' to go to the stamp
this doesn't exist, does it...
thanks for the explanation
Original Message
From: "Allan Lane" <allan.lane@h...>
To: <basicstamps@yahoogroups.com>
Sent: Monday, June 23, 2003 4:07 PM
Subject: [noparse][[/noparse]basicstamps] Re: Is there such a thing as an acoustic
array/matrix ?
> The goal here would be to measure the phase difference (difference in
> arrival times) at each microphone, then swing the two microphones to
> zero out the phase difference -- or use the phase difference to get
> a direction to the source. I'm not sure this
> is a task for the BS2, since in a 'noisy'
> environment determining the identity of a single
> sound, to find the start time of it,
> could be difficult.
>
> Human hearing is VERY good at differentiating
> sounds, and using the phase difference to
> determine a direction to the sound. That
> doesn't mean it's easy for a CPU.
>
> The CMU-Cam has an on-board processor which
> processes the pixels for you, to determine
> locations and movement for you.
>
>
> --- In basicstamps@yahoogroups.com, "rdenn25" <rad0@a...> wrote:
> > --- In basicstamps@yahoogroups.com, Dennis O'Leary <doleary@e...>
> > wrote:
> > > This would require an array of N directional microphones, where N
> > > 1, and N is determined by environmental factors and mike
> > > sensitivity/slectivity. On open prairie or water, 2 mikes or 2
> > human
> > > ears (with normal hearing) would do the task. Ask any duck
> > hunter. [noparse]:)[/noparse]
> > >
> > > Dennis
> > >
> >
> > bear with me. are you saying that I could make an
> > acoustic 'pointer/tracker' with two or three microphone?
> >
> > are there any examples of this thing for stamps or microcontrollers?
> > thanks
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
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> and
Body of the message will be ignored.
>
>
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> http://docs.yahoo.com/info/terms/
>
>
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this is very complicated, I thought that using loudness measurement
might work, but that's very complicated too
A simple approach to this would be to ignore phase and instead use amplitude
to determine direction. Using two microphones, you would need circuitry to
amplify (and adjust gain to balance the microphones) and a means to
determine amplitude of the two microphone signals (possibly a window
comparator circuit), then, the noise is coming from the general direction of
the louder signal. Move the microphone pair toward the louder noise and
when equal that is the direction to the noise source. It is best if the
noise is filtered to a narrow spectrum for best results as this would tend
to eliminate some interference from random environmental noise. Phase
comparison assumes that there are no reflective surfaces near the source or
receiver (mic) and the characteristics of the noise is known, however, using
phase along with amplitude can result in excellent performance but with more
extensive circuitry and signal processing. All the above circuitry can be
done with op-amps. I know that this involves analog design, but the real
world is analog, not digital.
jim
http://www.geocities.com/jimforkin2003/
Original Message
From: Allan Lane [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=S87djQ0zEBIpkAQ9Wi2klmLb8le40ZQFSld2-byFvoPsQpU7gIBPyXtqZ7bntOG2AjS5S_xN9gdT8kCFTIlKANBEU4pn]allan.lane@h...[/url
Sent: Monday, June 23, 2003 5:08 PM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] Re: Is there such a thing as an acoustic
array/matrix ?
The goal here would be to measure the phase difference
(difference in arrival times) at each microphone, then
swing the two microphones to zero out the phase
difference -- or use the phase difference to get
a direction to the source. I'm not sure this
is a task for the BS2, since in a 'noisy'
environment determining the identity of a single
sound, to find the start time of it,
could be difficult.
Human hearing is VERY good at differentiating
sounds, and using the phase difference to
determine a direction to the sound. That
doesn't mean it's easy for a CPU.
The CMU-Cam has an on-board processor which
processes the pixels for you, to determine
locations and movement for you.
--- In basicstamps@yahoogroups.com, "rdenn25" <rad0@a...> wrote:
> --- In basicstamps@yahoogroups.com, Dennis O'Leary <doleary@e...>
> wrote:
> > This would require an array of N directional microphones, where N
> > 1,
> > and N is determined by environmental factors and mike
> > sensitivity/slectivity. On open prairie or water, 2 mikes or 2
> human
> > ears (with normal hearing) would do the task. Ask any duck
> hunter. [noparse]:)[/noparse]
> >
> > Dennis
> >
>
> bear with me. are you saying that I could make an
> acoustic 'pointer/tracker' with two or three microphone?
>
> are there any examples of this thing for stamps or microcontrollers?
> thanks
To UNSUBSCRIBE, just send mail to:
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as I suggested earlier which involves taking a reading of all three at once
through a "Peak Detector" circuit (one for each mic), or a "digital snapshot"
of the ADC output at each mic. I was revisiting this idea last night, knowing
that the next question on this list would probably be how to interpret the
three vectors produced from each microphone into one solid vector representing
the sound origin... following up with this I will post a small visual demo
program I was playing with last night that lets you control where the source
is originating and "see" the amplitude each sensor experiences in relation to
the position of the sound source. This exercise is very intuitive to writing
STAMP/PIC code to decipher the location of a sound source based on the results
from your sensors. In a nutshell, it comes down to determining one of three
quadrants (? tri-rants ?) by a simple process of elimination. The remaining
two are weighted as a ratio of one another. By doing this you can negate any
amplitude variations that will most likely be varying at the source (Bird)
without effecting the direction results.
-Beau Schwabe
>Allan's, Beau's and my comments about sound localization all reduce to:
>you need at least 2 "receivers" (ears, microphones, or whatever), plus
>some electronic processing method of detecting small time differences in
>when the sound arrives at each receiver. Also, note that the
>"processor" must know the location of each of the receivers, and then
>solve some trigonometric equations to localize the sound source. Sounds
>simple, but solving trig equations is not what the Stamp is good at.
>
>Dennis
>
>
Original Message
>From: rad0 [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=2d9IH5bvmoiZedKZW-qkp3rj05MKze0SCA3OuEpt5mQ5C7TY0WnhrghLs1yIS1bD00EKuQ]rad0@a...[/url
>Sent: Monday, June 23, 2003 2:50 PM
>To: basicstamps@yahoogroups.com
>Subject: Re: [noparse][[/noparse]basicstamps] Re: Is there such a thing as an acoustic
>array/matrix ?
>
>
>Yeah OK, I see what you are saying
>
>instead of a microphone, to hook to the stamp,
>it would take an 'ear' to go to the stamp
>
>this doesn't exist, does it...
>
>thanks for the explanation
>
>
Original Message
>From: "Allan Lane" <allan.lane@h...>
>To: <basicstamps@yahoogroups.com>
>Sent: Monday, June 23, 2003 4:07 PM
>Subject: [noparse][[/noparse]basicstamps] Re: Is there such a thing as an acoustic
>array/matrix ?
>
>
> > The goal here would be to measure the phase difference (difference in
> > arrival times) at each microphone, then swing the two microphones to
> > zero out the phase difference -- or use the phase difference to get
> > a direction to the source. I'm not sure this
> > is a task for the BS2, since in a 'noisy'
> > environment determining the identity of a single
> > sound, to find the start time of it,
> > could be difficult.
> >
> > Human hearing is VERY good at differentiating
> > sounds, and using the phase difference to
> > determine a direction to the sound. That
> > doesn't mean it's easy for a CPU.
> >
> > The CMU-Cam has an on-board processor which
> > processes the pixels for you, to determine
> > locations and movement for you.
> >
> >
> > --- In basicstamps@yahoogroups.com, "rdenn25" <rad0@a...> wrote:
> > > --- In basicstamps@yahoogroups.com, Dennis O'Leary <doleary@e...>
> > > wrote:
> > > > This would require an array of N directional microphones, where N
> > > > 1, and N is determined by environmental factors and mike
> > > > sensitivity/slectivity. On open prairie or water, 2 mikes or 2
> > > human
> > > > ears (with normal hearing) would do the task. Ask any duck
> > > hunter. [noparse]:)[/noparse]
> > > >
> > > > Dennis
> > > >
> > >
> > > bear with me. are you saying that I could make an
> > > acoustic 'pointer/tracker' with two or three microphone?
> > >
> > > are there any examples of this thing for stamps or microcontrollers?
>
> > > thanks
> >
> >
> > 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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>
>
>
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degrees apart. You should be able to write 3 equations, enter the trig values
for sines & cosines (angles are fixed) and invert the matrix. Then the problem
is reduced to multiplications.
Dennis O'Leary <doleary@e...> wrote:Allan's, Beau's and my comments
about sound localization all reduce to:
you need at least 2 "receivers" (ears, microphones, or whatever), plus
some electronic processing method of detecting small time differences in
when the sound arrives at each receiver. Also, note that the
"processor" must know the location of each of the receivers, and then
solve some trigonometric equations to localize the sound source. Sounds
simple, but solving trig equations is not what the Stamp is good at.
Dennis
Original Message
From: rad0 [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=LjiwhJDkt0_1vR5nJXfFaMeuCPZ-WIlsUY8I0Y65KOhWHd2pR1l487FQyulX3SThPkRfT1L2XQ]rad0@a...[/url
Sent: Monday, June 23, 2003 2:50 PM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] Re: Is there such a thing as an acoustic
array/matrix ?
Yeah OK, I see what you are saying
instead of a microphone, to hook to the stamp,
it would take an 'ear' to go to the stamp
this doesn't exist, does it...
thanks for the explanation
Original Message
From: "Allan Lane"
To:
Sent: Monday, June 23, 2003 4:07 PM
Subject: [noparse][[/noparse]basicstamps] Re: Is there such a thing as an acoustic
array/matrix ?
> The goal here would be to measure the phase difference (difference in
> arrival times) at each microphone, then swing the two microphones to
> zero out the phase difference -- or use the phase difference to get
> a direction to the source. I'm not sure this
> is a task for the BS2, since in a 'noisy'
> environment determining the identity of a single
> sound, to find the start time of it,
> could be difficult.
>
> Human hearing is VERY good at differentiating
> sounds, and using the phase difference to
> determine a direction to the sound. That
> doesn't mean it's easy for a CPU.
>
> The CMU-Cam has an on-board processor which
> processes the pixels for you, to determine
> locations and movement for you.
>
>
> --- In basicstamps@yahoogroups.com, "rdenn25" wrote:
> > --- In basicstamps@yahoogroups.com, Dennis O'Leary
> > wrote:
> > > This would require an array of N directional microphones, where N
> > > 1, and N is determined by environmental factors and mike
> > > sensitivity/slectivity. On open prairie or water, 2 mikes or 2
> > human
> > > ears (with normal hearing) would do the task. Ask any duck
> > hunter. [noparse]:)[/noparse]
> > >
> > > Dennis
> > >
> >
> > bear with me. are you saying that I could make an
> > acoustic 'pointer/tracker' with two or three microphone?
> >
> > are there any examples of this thing for stamps or microcontrollers?
> > thanks
>
>
> 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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[noparse][[/noparse]Non-text portions of this message have been removed]
implementing 3 mics arranged 120 deg apart. The only real
thing to consider mechanically is that the mics are directional.
A simple solution would be to cut the bottom 1-2 inches off of
an 8 inch diameter plastic barrel and place your three mics
about 8 and 3/8 inches apart along the circumference. Or some
other "circular" form in place of the barrel.
'
QBASIC program Starts here
Pi# = ATN(1) * 4
'
Screen Setup
SCREEN 12
WINDOW (-266, -200)-(266, 200)
FOR Deg = 0 TO 360 STEP .5
Rad# = (Deg / 180) * Pi#
X1 = COS(Rad#) * 74
Y1 = SIN(Rad#) * 74
X2 = COS(Rad#) * 86
Y2 = SIN(Rad#) * 86
PSET (X1, Y1), 14
PSET (X2, Y2), 14
NEXT Deg
LOCATE 3, 59: PRINT "A B C Sensor values."
LOCATE 4, 58: PRINT "-"
LOCATE 15, 58: PRINT "+"
LOCATE 2, 1: PRINT "Use '+' and '-' keys to move source"
LOCATE 3, 1: PRINT "Use 'Esc' key to exit"
LOCATE 5, 1: COLOR 14: PRINT "Yellow"; : COLOR 15:
PRINT " bar in the circle is the Signal source."
LOCATE 6, 1: COLOR 1: PRINT "Blue"; : COLOR 15:
PRINT " bar in the circle points to the Calculated source."
'
Calculate Fixed sensor position and Draw
Rad1# = (0 / 180) * Pi#
Rad2# = (120 / 180) * Pi#
Rad3# = (240 / 180) * Pi#
Xsensor1 = COS(Rad1#) * 65
Ysensor1 = SIN(Rad1#) * 65
Xsensor2 = COS(Rad2#) * 65
Ysensor2 = SIN(Rad2#) * 65
Xsensor3 = COS(Rad3#) * 65
Ysensor3 = SIN(Rad3#) * 65
CIRCLE (Xsensor1, Ysensor1), 5, 14
LOCATE 15, 49: PRINT "A"
CIRCLE (Xsensor2, Ysensor2), 5, 14
LOCATE 12, 37: PRINT "B"
CIRCLE (Xsensor3, Ysensor3), 5, 14
LOCATE 19, 37: PRINT "C"
'
Main Program Loop
Deg = 0
WHILE Z <> 1
Z = INP(&H60)
Z$ = INKEY$
WAIT 986, 8 'screen refresh delay
'
Keypress logic
IF Z = 78 OR Z = 13 THEN '+' Key
Deg = Deg + 5
IF Deg >= 360 THEN Deg = 0
END IF
IF Z = 74 OR Z = 12 THEN '-' Key
Deg = Deg - 5
IF Deg <= 0 THEN Deg = 360
END IF
'
Calculate Source Location and Draw indicator
Rad1# = (Deg / 180) * Pi#
XsourceOld1 = Xsource1
YsourceOld1 = Ysource1
XsourceOld2 = Xsource2
YsourceOld2 = Ysource2
Xsource1 = COS(Rad1#) * 75
Ysource1 = SIN(Rad1#) * 75
Xsource2 = COS(Rad1#) * 85
Ysource2 = SIN(Rad1#) * 85
IF XsourceOld1 <> Xsource1 OR YsourceOld1 <> Ysource1 THEN
LINE (XsourceOld1, YsourceOld1)-(XsourceOld2, YsourceOld2), 0
LINE (Xsource1, Ysource1)-(Xsource2, Ysource2), 14
END IF
'
Calculate Each Sensor Distance from Source Location
DX1Old = DX1
DX2Old = DX2
DX3Old = DX3
DX1 = INT(SQR((Xsource1 - Xsensor1) ^ 2 + (Ysource1 - Ysensor1) ^ 2))
DX2 = INT(SQR((Xsource1 - Xsensor2) ^ 2 + (Ysource1 - Ysensor2) ^ 2))
DX3 = INT(SQR((Xsource1 - Xsensor3) ^ 2 + (Ysource1 - Ysensor3) ^ 2))
'Note there is an inversion that takes place here between the relationship
'of equating Distance to Amplitude that should be considered.
'---Determine Sensor that is furthest away ...Notice >= positioning...
IF DX1 >= DX2 AND DX1 > DX3 THEN
C1 = 12
Position = 1 + (DX2 / (DX2 + DX3))
ELSE
C1 = 10
END IF
IF DX2 > DX1 AND DX2 >= DX3 THEN
C2 = 12
Position = 2 + (DX3 / (DX1 + DX3))
ELSE
C2 = 10
END IF
IF DX3 >= DX1 AND DX3 > DX2 THEN
C3 = 12
Position = 0 + (DX1 / (DX1 + DX2))
ELSE
C3 = 10
END IF
'---Calculate Source direction from the two closest sensors and display---
'
'In this example the Calculated value is in Radians...
'
'...if you want Degrees:
'
' DEGPosition = (Position * 360) / 3
'
'...if you want a value ranging from 0 to 100 then...
'
'
' Percent = (Position * 100) / 3
'
OldXPos = XPosition
OldYPos = YPosition
RADPosition# = (Position * Pi# * 2) / 3
XPosition = COS(RADPosition#) * 40
YPosition = SIN(RADPosition#) * 40
IF OldXPos <> XPosition OR OldYPos <> YPosition THEN
LINE (OldXPos, OldYPos)-(0, 0), 0
ELSE
LINE (XPosition, YPosition)-(0, 0), 1
END IF
'
Visually indicate Furthest sensor
PAINT (Xsensor1, Ysensor1), C1, 14
PAINT (Xsensor2, Ysensor2), C2, 14
PAINT (Xsensor3, Ysensor3), C3, 14
'
Visually indicate each sensors strength
IF DX1Old <> DX1 THEN
LINE (120, 150)-(125, DX1Old), C1, BF
LINE (120, 0)-(125, DX1), 0, BF
END IF
IF DX2Old <> DX2 THEN
LINE (134, 150)-(139, DX2Old), C2, BF
LINE (134, 0)-(139, DX2), 0, BF
END IF
IF DX3Old <> DX3 THEN
LINE (148, 150)-(153, DX3Old), C3, BF
LINE (148, 0)-(153, DX3), 0, BF
END IF
WEND
'
QBASIC program Ends here
it, it might be done with a Stamp if you skip the graphics.
Dennis
Original Message
From: Beau Schwabe [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=r_6WWa__0sKqQ6m8ZnzT4-WcEPOplGQeZbR5mYhLN7UkQ2p8MihtJLY2fUwbsNJUmlheMxdjx64MNx26v4VvF_Kl]bschwabe@a...[/url
Sent: Wednesday, June 25, 2003 7:28 AM
To: basicstamps@yahoogroups.com
Subject: RE: [noparse][[/noparse]basicstamps] Re: Is there such a thing as an acoustic
array/matrix ?
Here is the QBASIC program that I have been twiddling with implementing
3 mics arranged 120 deg apart. The only real thing to consider
mechanically is that the mics are directional. A simple solution would
be to cut the bottom 1-2 inches off of an 8 inch diameter plastic barrel
and place your three mics about 8 and 3/8 inches apart along the
circumference. Or some other "circular" form in place of the barrel.
'
QBASIC program Starts here
Pi# = ATN(1) * 4
'
Screen Setup
SCREEN 12
WINDOW (-266, -200)-(266, 200) FOR Deg = 0 TO 360 STEP .5
Rad# = (Deg / 180) * Pi#
X1 = COS(Rad#) * 74
Y1 = SIN(Rad#) * 74
X2 = COS(Rad#) * 86
Y2 = SIN(Rad#) * 86
PSET (X1, Y1), 14
PSET (X2, Y2), 14
NEXT Deg
LOCATE 3, 59: PRINT "A B C Sensor values."
LOCATE 4, 58: PRINT "-"
LOCATE 15, 58: PRINT "+"
LOCATE 2, 1: PRINT "Use '+' and '-' keys to move source"
LOCATE 3, 1: PRINT "Use 'Esc' key to exit"
LOCATE 5, 1: COLOR 14: PRINT "Yellow"; : COLOR 15:
PRINT " bar in the circle is the Signal source."
LOCATE 6, 1: COLOR 1: PRINT "Blue"; : COLOR 15:
PRINT " bar in the circle points to the Calculated source."
'
Calculate Fixed sensor position and Draw
Rad1# = (0
/ 180) * Pi# Rad2# = (120 / 180) * Pi# Rad3# = (240 / 180) * Pi#
Xsensor1 = COS(Rad1#) * 65 Ysensor1 = SIN(Rad1#) * 65 Xsensor2 =
COS(Rad2#) * 65 Ysensor2 = SIN(Rad2#) * 65 Xsensor3 = COS(Rad3#) * 65
Ysensor3 = SIN(Rad3#) * 65 CIRCLE (Xsensor1, Ysensor1), 5, 14 LOCATE 15,
49: PRINT "A" CIRCLE (Xsensor2, Ysensor2), 5, 14 LOCATE 12, 37: PRINT
"B" CIRCLE (Xsensor3, Ysensor3), 5, 14 LOCATE 19, 37: PRINT "C"
'
Main Program Loop
Deg = 0
WHILE Z <> 1
Z = INP(&H60)
Z$ = INKEY$
WAIT 986, 8 'screen refresh delay
'
Keypress logic
IF Z = 78 OR Z = 13 THEN '+' Key
Deg = Deg + 5
IF Deg >= 360 THEN Deg = 0
END IF
IF Z = 74 OR Z = 12 THEN '-' Key
Deg = Deg - 5
IF Deg <= 0 THEN Deg = 360
END IF
'
Calculate Source Location and Draw indicator
Rad1# = (Deg / 180) * Pi#
XsourceOld1 = Xsource1
YsourceOld1 = Ysource1
XsourceOld2 = Xsource2
YsourceOld2 = Ysource2
Xsource1 = COS(Rad1#) * 75
Ysource1 = SIN(Rad1#) * 75
Xsource2 = COS(Rad1#) * 85
Ysource2 = SIN(Rad1#) * 85
IF XsourceOld1 <> Xsource1 OR YsourceOld1 <> Ysource1 THEN
LINE (XsourceOld1, YsourceOld1)-(XsourceOld2, YsourceOld2), 0
LINE (Xsource1, Ysource1)-(Xsource2, Ysource2), 14
END IF
'
Calculate Each Sensor Distance from Source Location
DX1Old = DX1
DX2Old = DX2
DX3Old = DX3
DX1 = INT(SQR((Xsource1 - Xsensor1) ^ 2 + (Ysource1 - Ysensor1) ^ 2))
DX2 = INT(SQR((Xsource1 - Xsensor2) ^ 2 + (Ysource1 - Ysensor2) ^ 2))
DX3 = INT(SQR((Xsource1 - Xsensor3) ^ 2 + (Ysource1 - Ysensor3) ^ 2))
'Note there is an inversion that takes place here between the
relationship 'of equating Distance to Amplitude that should be
considered.
'---Determine Sensor that is furthest away ...Notice >= positioning...
IF DX1 >= DX2 AND DX1 > DX3 THEN
C1 = 12
Position = 1 + (DX2 / (DX2 + DX3))
ELSE
C1 = 10
END IF
IF DX2 > DX1 AND DX2 >= DX3 THEN
C2 = 12
Position = 2 + (DX3 / (DX1 + DX3))
ELSE
C2 = 10
END IF
IF DX3 >= DX1 AND DX3 > DX2 THEN
C3 = 12
Position = 0 + (DX1 / (DX1 + DX2))
ELSE
C3 = 10
END IF
'---Calculate Source direction from the two closest sensors and
display--- ' 'In this example the Calculated value is in Radians... '
'...if you want Degrees: '
' DEGPosition = (Position * 360) / 3
'
'...if you want a value ranging from 0 to 100 then...
'
'
' Percent = (Position * 100) / 3
'
OldXPos = XPosition
OldYPos = YPosition
RADPosition# = (Position * Pi# * 2) / 3
XPosition = COS(RADPosition#) * 40
YPosition = SIN(RADPosition#) * 40
IF OldXPos <> XPosition OR OldYPos <> YPosition THEN
LINE (OldXPos, OldYPos)-(0, 0), 0
ELSE
LINE (XPosition, YPosition)-(0, 0), 1
END IF
'
Visually indicate Furthest sensor
PAINT (Xsensor1, Ysensor1), C1, 14
PAINT (Xsensor2, Ysensor2), C2, 14
PAINT (Xsensor3, Ysensor3), C3, 14
'
Visually indicate each sensors strength
IF DX1Old <> DX1 THEN
LINE (120, 150)-(125, DX1Old), C1, BF
LINE (120, 0)-(125, DX1), 0, BF
END IF
IF DX2Old <> DX2 THEN
LINE (134, 150)-(139, DX2Old), C2, BF
LINE (134, 0)-(139, DX2), 0, BF
END IF
IF DX3Old <> DX3 THEN
LINE (148, 150)-(153, DX3Old), C3, BF
LINE (148, 0)-(153, DX3), 0, BF
END IF
WEND
'
QBASIC program Ends here
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sophisticated, but I'm looking at the output of a pulsed ultrasound
emitter, as received by a mike attached to a 'scope input. The space
is a room with sheet rock walls and lots of other reflecting
surfaces. The amplifier gain is turned way up. The ultrasound is so
directional that often the echo is much stronger than the direct beam.
-- Tracy
>Here is the QBASIC program that I have been twiddling with
>implementing 3 mics arranged 120 deg apart. The only real
>thing to consider mechanically is that the mics are directional.
>A simple solution would be to cut the bottom 1-2 inches off of
>an 8 inch diameter plastic barrel and place your three mics
>about 8 and 3/8 inches apart along the circumference. Or some
>other "circular" form in place of the barrel.
>...
reflect sound as though you are in a concrete box.
Let me re-think this...
>I wonder how to deal with echoes? I haven't done anything this
>sophisticated, but I'm looking at the output of a pulsed ultrasound
>emitter, as received by a mike attached to a 'scope input. The space
>is a room with sheet rock walls and lots of other reflecting
>surfaces. The amplifier gain is turned way up. The ultrasound is so
>directional that often the echo is much stronger than the direct beam.
>
> -- Tracy
>
>
> >Here is the QBASIC program that I have been twiddling with
> >implementing 3 mics arranged 120 deg apart. The only real
> >thing to consider mechanically is that the mics are directional.
> >A simple solution would be to cut the bottom 1-2 inches off of
> >an 8 inch diameter plastic barrel and place your three mics
> >about 8 and 3/8 inches apart along the circumference. Or some
> >other "circular" form in place of the barrel.
> >...
The original post (not from me) was asking about bird calls.
Definitely not ultrasound. I'm interested in bats. Of course, bats
are quite good at the echolocation based on two ears. I'm even more
amazed when I look at ultrasound echos on a 'scope. Must be some
good "neurodigital" processing going on. Right now we have
microphones that simply tell if they are there or not. The mike is
placed low and looking up over a water surface. People always ask
about automatic localization.
Here is a funny thing that happened to one of the microphones:
<http://www.emesystems.com/bathat.htm>
-- Tracy
>Ultrasound is a different story... It makes just about everything
>reflect sound as though you are in a concrete box.
>
>Let me re-think this...
>
>>I wonder how to deal with echoes? I haven't done anything this
>>sophisticated, but I'm looking at the output of a pulsed ultrasound
>>emitter, as received by a mike attached to a 'scope input. The space
>>is a room with sheet rock walls and lots of other reflecting
>>surfaces. The amplifier gain is turned way up. The ultrasound is so
>>directional that often the echo is much stronger than the direct beam.
>>
>> -- Tracy
>>
>>
>> >Here is the QBASIC program that I have been twiddling with
>> >implementing 3 mics arranged 120 deg apart. The only real
>> >thing to consider mechanically is that the mics are directional.
>> >A simple solution would be to cut the bottom 1-2 inches off of
>> >an 8 inch diameter plastic barrel and place your three mics
>> >about 8 and 3/8 inches apart along the circumference. Or some
>> >other "circular" form in place of the barrel.
>> >...
>
>
>
>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/
(HRTF) which is a mathematical model of how we hear a 3D world binaurally
with only two ears. By calculating timing/phase cues, amplitude differences,
and comb filtering effects (due to the folds inside our ears), we can easily
localize a full surround field. The room reflections are indeed a part of
what our brain learns about its immediate environment, making it much
quicker at locating an object in a room we've acclimated to. It's also why
we move our heads from side to side to help figure out where a sound is
coming from. We're scanning the room and building a model of it in our
heads.
So by using a binaural head, something like a plastic dummy head with a pair
of mic elements in the ear canals, and applying an HRTF function, it should
be possible to determine the location of a sound source with XYZ
coordinates.
Now, this is probably not a simple thing you can do in a stamp. It usually
taxes the processing power of a souped up P4 or dedicated DSP chip. Still,
it's something to think about for this sort of thing. There may be a way to
strip this down to the basic formula if only a single frequency, or perhaps
multiple tones, were involved.
Mike Sokol
www.modernrecording.com
mikes@m...
301-739-6842 voice/fax
301-964-5682 mobile
Original Message
From: "Sadler Porter" <porter.sadler@s...>
To: <basicstamps@yahoogroups.com>
Sent: Wednesday, June 25, 2003 5:47 PM
Subject: RE: [noparse][[/noparse]basicstamps] Re: Is there such a thing as an acoustic
array/matrix ?
> Yes you have access to very good one. (your ears). Your mind note the
> slight differences in the time the sound reaches your two ears and that
give
> you the since of direction for the source.
>
>
Original Message
> From: rdenn25 [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=NAq61xKKaWH5Y1FImNEh1m6YWTGaq54vCTg2i0ZRik3oQi93CvtBRwK5lwmY9YT6asfEgPx0YZM]rad0@a...[/url
> Sent: Friday, June 20, 2003 10:56 PM
> To: basicstamps@yahoogroups.com
> Subject: [noparse][[/noparse]basicstamps] Re: Is there such a thing as an acoustic
> array/matrix ?
>
>
>
> bear with me. are you saying that I could make an
> acoustic 'pointer/tracker' with two or three microphone?
>
> are there any examples of this thing for stamps or microcontrollers?
> thanks
>
>
>
> 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/
>
>
>
> [noparse][[/noparse]Non-text portions of this message have been removed]
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
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Body of the message will be ignored.
>
>
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>
microphone(s) into discrete frequencies or pigeonholes?
> I wonder how to deal with echoes?
>
> -- Tracy
>
Could you deal with the echo by using a special horn? A shaped
inlet for the microphone, simulating the bats' ear lobe. You could
make a complex shape using fiberglass or composites. I've never
understood why microphones don't look more like ears.
The first thing a dog does when he hears something, is reposition
his ear lobes (horn) and cock his head. The head cock may be more
communication or emotion than a refinement of his hearing apparatus
though.
problem that much. That the ear canal does is cause a frequency dip around 3
kHz or so for sounds located directly in front... at 0 degree axis. Sound
sources at 90 and 180 degree axis (directly beaming into your ear canal)
sound "brighter" due to this effect. The pinnae, ear canal, etc., all
interact to cause a constantly changing panorama of frequency response,
phase shifts, and temporal (timing) cues that allow us to localize sources
quite easily.
See
http://human-factors.arc.nasa.gov/ihh/spatial/papers/pdfs_db/AEStutorial10.0
2_USETHIS.ppt
for a pretty good paper on the subject.
Mike Sokol
www.modernrecording.com
mikes@m...
Original Message
From: "rdenn25" <rad0@a...>
To: <basicstamps@yahoogroups.com>
Sent: Wednesday, June 25, 2003 10:28 PM
Subject: [noparse][[/noparse]basicstamps] Re: Is there such a thing as an acoustic array/matrix
?
> --- In basicstamps@yahoogroups.com, Tracy Allen <tracy@e...> wrote:
>
> > I wonder how to deal with echoes?
> >
> > -- Tracy
> >
> Could you deal with the echo by using a special horn? A shaped
> inlet for the microphone, simulating the bats' ear lobe. You could
> make a complex shape using fiberglass or composites. I've never
> understood why microphones don't look more like ears.
>
> The first thing a dog does when he hears something, is reposition
> his ear lobes (horn) and cock his head. The head cock may be more
> communication or emotion than a refinement of his hearing apparatus
> though.
>
>
> 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/
>
Yes, I realize the original post was about bird calls...
Here are just some ideas:
1)Perhaps we are thinking about the idea of using ultrasound in the
wrong direction. "Ideally" you would expect an audio signal to decay
instead of re-enforcing itself. With that said there should be a
way to de-tune or adjust the sensor position slightly so that the
signal received does not introduce positive or negative re-enforcement
based on the surroundings. (precision servo mounted ultrasonic sensors?)
If your sensors are in a fixed location, then this sort of calibration
should only need minimal adjustments.
2)The idea of a special horn might work if the design intention was to
make the sensor less directional.
3)Reducing the amount of power driving your ultrasonics might help reduce
echoing.
4)What happens if you send a steady bombardment of ultrasound instead
of pulsing it? - Just curious The "pulsing" could cause extra ringing
or noise in objects that would otherwise be considered "ultrasonically
quiet".
-Beau Schwabe
>Hi Beau,
>
>The original post (not from me) was asking about bird calls.
>Definitely not ultrasound. I'm interested in bats. Of course, bats
>are quite good at the echolocation based on two ears. I'm even more
>amazed when I look at ultrasound echos on a 'scope. Must be some
>good "neurodigital" processing going on. Right now we have
>microphones that simply tell if they are there or not. The mike is
>placed low and looking up over a water surface. People always ask
>about automatic localization.
>
> Here is a funny thing that happened to one of the microphones:
><http://www.emesystems.com/bathat.htm>
>
> -- Tracy
>
>
>
> >Ultrasound is a different story... It makes just about everything
> >reflect sound as though you are in a concrete box.
> >
> >Let me re-think this...
> >
> >>I wonder how to deal with echoes? I haven't done anything this
> >>sophisticated, but I'm looking at the output of a pulsed ultrasound
> >>emitter, as received by a mike attached to a 'scope input. The space
> >>is a room with sheet rock walls and lots of other reflecting
> >>surfaces. The amplifier gain is turned way up. The ultrasound is so
> >>directional that often the echo is much stronger than the direct beam.
> >>
> >> -- Tracy
> >>
> >>
> >> >Here is the QBASIC program that I have been twiddling with
> >> >implementing 3 mics arranged 120 deg apart. The only real
> >> >thing to consider mechanically is that the mics are directional.
> >> >A simple solution would be to cut the bottom 1-2 inches off of
> >> >an 8 inch diameter plastic barrel and place your three mics
> >> >about 8 and 3/8 inches apart along the circumference. Or some
> >> >other "circular" form in place of the barrel.
> >> >...
At what frequency do bats "PING" their environment?
Does it vary, if so how much? ...from species to species?
My thought was, would it be possible to setup a BFO (Beat
Frequency Oscillator) similar to older style metal detector
designs... If applied to bats, this would translate into a
Doppler shift of frequency that would contain information
relating to the Bats position, stationary or in flight.
-Beau Schwabe
>Tracy,
>
>Yes, I realize the original post was about bird calls...
>
>Here are just some ideas:
>
>1)Perhaps we are thinking about the idea of using ultrasound in the
> wrong direction. "Ideally" you would expect an audio signal to decay
> instead of re-enforcing itself. With that said there should be a
> way to de-tune or adjust the sensor position slightly so that the
> signal received does not introduce positive or negative re-enforcement
> based on the surroundings. (precision servo mounted ultrasonic sensors?)
> If your sensors are in a fixed location, then this sort of calibration
> should only need minimal adjustments.
>
>2)The idea of a special horn might work if the design intention was to
> make the sensor less directional.
>
>3)Reducing the amount of power driving your ultrasonics might help reduce
> echoing.
>
>4)What happens if you send a steady bombardment of ultrasound instead
> of pulsing it? - Just curious The "pulsing" could cause extra ringing
> or noise in objects that would otherwise be considered "ultrasonically
> quiet".
>
>-Beau Schwabe
>
>
> >Hi Beau,
> >
> >The original post (not from me) was asking about bird calls.
> >Definitely not ultrasound. I'm interested in bats. Of course, bats
> >are quite good at the echolocation based on two ears. I'm even more
> >amazed when I look at ultrasound echos on a 'scope. Must be some
> >good "neurodigital" processing going on. Right now we have
> >microphones that simply tell if they are there or not. The mike is
> >placed low and looking up over a water surface. People always ask
> >about automatic localization.
> >
> > Here is a funny thing that happened to one of the microphones:
> ><http://www.emesystems.com/bathat.htm>
> >
> > -- Tracy
> >
> >
> >
> > >Ultrasound is a different story... It makes just about everything
> > >reflect sound as though you are in a concrete box.
> > >
> > >Let me re-think this...
> > >
> > >>I wonder how to deal with echoes? I haven't done anything this
> > >>sophisticated, but I'm looking at the output of a pulsed ultrasound
> > >>emitter, as received by a mike attached to a 'scope input. The space
> > >>is a room with sheet rock walls and lots of other reflecting
> > >>surfaces. The amplifier gain is turned way up. The ultrasound is so
> > >>directional that often the echo is much stronger than the direct beam.
> > >>
> > >> -- Tracy
> > >>
> > >>
> > >> >Here is the QBASIC program that I have been twiddling with
> > >> >implementing 3 mics arranged 120 deg apart. The only real
> > >> >thing to consider mechanically is that the mics are directional.
> > >> >A simple solution would be to cut the bottom 1-2 inches off of
> > >> >an 8 inch diameter plastic barrel and place your three mics
> > >> >about 8 and 3/8 inches apart along the circumference. Or some
> > >> >other "circular" form in place of the barrel.
> > >> >...
>
>
>
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frequencies. Several models of heterodyne "bat detectors", are
available at Bat Conservation International. The deluxe model has time
expansion and a digital display <
http://www.batcon.org/catalog/batdetectors.html >.
Dennis
Original Message
From: Beau Schwabe [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=wd3w07DAg4A_45d9MZb5TzzpmYrEofqZE8IochH0lf_D6VwUW-gH9WHYvaKJX2lWuRLkyIC2H2ctG5-rNYKcAVjB]bschwabe@a...[/url
Sent: Thursday, June 26, 2003 8:05 AM
To: basicstamps@yahoogroups.com
Subject: RE: [noparse][[/noparse]basicstamps] Re: Is there such a thing as an acoustic
array/matrix ?
Another thought...
At what frequency do bats "PING" their environment?
Does it vary, if so how much? ...from species to species?
My thought was, would it be possible to setup a BFO (Beat Frequency
Oscillator) similar to older style metal detector designs... If applied
to bats, this would translate into a Doppler shift of frequency that
would contain information relating to the Bats position, stationary or
in flight.
-Beau Schwabe
>Tracy,
>
>Yes, I realize the original post was about bird calls...
>
>Here are just some ideas:
>
>1)Perhaps we are thinking about the idea of using ultrasound in the
> wrong direction. "Ideally" you would expect an audio signal to
decay
> instead of re-enforcing itself. With that said there should be a
> way to de-tune or adjust the sensor position slightly so that the
> signal received does not introduce positive or negative
re-enforcement
> based on the surroundings. (precision servo mounted ultrasonic
sensors?)
> If your sensors are in a fixed location, then this sort of
calibration
> should only need minimal adjustments.
>
>2)The idea of a special horn might work if the design intention was to
> make the sensor less directional.
>
>3)Reducing the amount of power driving your ultrasonics might help
reduce
> echoing.
>
>4)What happens if you send a steady bombardment of ultrasound instead
> of pulsing it? - Just curious The "pulsing" could cause extra
ringing
> or noise in objects that would otherwise be considered
"ultrasonically
> quiet".
>
>-Beau Schwabe
>
>
> >Hi Beau,
> >
> >The original post (not from me) was asking about bird calls.
> >Definitely not ultrasound. I'm interested in bats. Of course, bats
> >are quite good at the echolocation based on two ears. I'm even more
> >amazed when I look at ultrasound echos on a 'scope. Must be some
> >good "neurodigital" processing going on. Right now we have
> >microphones that simply tell if they are there or not. The mike is
> >placed low and looking up over a water surface. People always ask
> >about automatic localization.
> >
> > Here is a funny thing that happened to one of the microphones:
> ><http://www.emesystems.com/bathat.htm>
> >
> > -- Tracy
> >
> >
> >
> > >Ultrasound is a different story... It makes just about everything
> > >reflect sound as though you are in a concrete box.
> > >
> > >Let me re-think this...
> > >
> > >>I wonder how to deal with echoes? I haven't done anything this
> > >>sophisticated, but I'm looking at the output of a pulsed
> > >>ultrasound emitter, as received by a mike attached to a 'scope
> > >>input. The space is a room with sheet rock walls and lots of
> > >>other reflecting surfaces. The amplifier gain is turned way up.
> > >>The ultrasound is so directional that often the echo is much
> > >>stronger than the direct beam.
> > >>
> > >> -- Tracy
> > >>
> > >>
> > >> >Here is the QBASIC program that I have been twiddling with
> > >> >implementing 3 mics arranged 120 deg apart. The only real thing
> > >> >to consider mechanically is that the mics are directional. A
> > >> >simple solution would be to cut the bottom 1-2 inches off of an
> > >> >8 inch diameter plastic barrel and place your three mics about 8
> > >> >and 3/8 inches apart along the circumference. Or some other
> > >> >"circular" form in place of the barrel. ...
>
>
>
>To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
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and
>Body of the message will be ignored.
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http://docs.yahoo.com/info/terms/
To UNSUBSCRIBE, just send mail to:
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of Australia. The bat calls can be recorded automatically on a CF
card. A stamp is monitoring the solar power and environmental
factors. These frequency division detectors lose the amplitude
information, but the frequency itself is very telling.
Bat echolocation signals often sweep rapidly down from a high
frequency and hover for a few milliseconds at a lower frequency, a
"J" curve. The main frequency does vary by species and can be from
18khz to 60 khz depending on species. The signal is labile, even
from time to time with one bat as it adapts to new conditions. In
crowded conditions with many bats, the signals can overlap and adapt
to that too. By analyzing the recorded signals, the researchers can
tell which bat species were present at what time and also get an idea
of what they was doing. I think they have even developed some
computer aided analysis software.
Right now the mike is place fairly near the ground by the shore, to
capture signals of both low flying "skimmers" near the shore and also
high flyers further out. Unfortunately, the budget does not allow a
lot of duplication.
-- Tracy
>Bat spectra vary with species, and are broad-band instead of single
>frequencies. Several models of heterodyne "bat detectors", are
>available at Bat Conservation International. The deluxe model has time
>expansion and a digital display <
>http://www.batcon.org/catalog/batdetectors.html >.
>
>Dennis
>
>
Original Message
>From: Beau Schwabe [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=3xKMvHI3ZjOI0HZXCDK2Igq9HJ4_p-ef6_S0qn310naRgqr2WN5I8b6KzV7tcH46_Xcw96wKTH1SnjThiVuOeJTR]bschwabe@a...[/url
>Sent: Thursday, June 26, 2003 8:05 AM
>To: basicstamps@yahoogroups.com
>Subject: RE: [noparse][[/noparse]basicstamps] Re: Is there such a thing as an acoustic
>array/matrix ?
>
>
>Another thought...
>
>At what frequency do bats "PING" their environment?
>Does it vary, if so how much? ...from species to species?
>
>My thought was, would it be possible to setup a BFO (Beat Frequency
>Oscillator) similar to older style metal detector designs... If applied
>to bats, this would translate into a Doppler shift of frequency that
>would contain information relating to the Bats position, stationary or
>in flight.
>
>-Beau Schwabe
>
>>Tracy,
>>
>>Yes, I realize the original post was about bird calls...
>>
>>Here are just some ideas:
>>
>>1)Perhaps we are thinking about the idea of using ultrasound in the
>> wrong direction. "Ideally" you would expect an audio signal to
>decay
>> instead of re-enforcing itself. With that said there should be a
>> way to de-tune or adjust the sensor position slightly so that the
>> signal received does not introduce positive or negative
>re-enforcement
>> based on the surroundings. (precision servo mounted ultrasonic
>sensors?)
>> If your sensors are in a fixed location, then this sort of
>calibration
>> should only need minimal adjustments.
>>
>>2)The idea of a special horn might work if the design intention was to
>> make the sensor less directional.
>>
>>3)Reducing the amount of power driving your ultrasonics might help
>reduce
>> echoing.
>>
>>4)What happens if you send a steady bombardment of ultrasound instead
>> of pulsing it? - Just curious The "pulsing" could cause extra
>ringing
>> or noise in objects that would otherwise be considered
>"ultrasonically
>> quiet".
>>
>>-Beau Schwabe
> >
> >
> > >Hi Beau,
> > >
> > >The original post (not from me) was asking about bird calls.
> > >Definitely not ultrasound. I'm interested in bats. Of course, bats
> > >are quite good at the echolocation based on two ears. I'm even more
>> >amazed when I look at ultrasound echos on a 'scope. Must be some
>> >good "neurodigital" processing going on. Right now we have
>> >microphones that simply tell if they are there or not. The mike is
>> >placed low and looking up over a water surface. People always ask
>> >about automatic localization.
>> >
>> > Here is a funny thing that happened to one of the microphones:
>> ><http://www.emesystems.com/bathat.htm>
> > >
>> > -- Tracy
>> >
>> >
>> >
>> > >Ultrasound is a different story... It makes just about everything
>> > >reflect sound as though you are in a concrete box.
>> > >
>> > >Let me re-think this...
>> > >
>> > >>I wonder how to deal with echoes? I haven't done anything this
>> > >>sophisticated, but I'm looking at the output of a pulsed
>> > >>ultrasound emitter, as received by a mike attached to a 'scope
>> > >>input. The space is a room with sheet rock walls and lots of
>> > >>other reflecting surfaces. The amplifier gain is turned way up.
>> > >>The ultrasound is so directional that often the echo is much
>> > >>stronger than the direct beam.
>> > >>
>> > >> -- Tracy
>> > >>
>> > >>
>> > >> >Here is the QBASIC program that I have been twiddling with
>> > >> >implementing 3 mics arranged 120 deg apart. The only real thing
>
>> > >> >to consider mechanically is that the mics are directional. A
>> > >> >simple solution would be to cut the bottom 1-2 inches off of an
>> > >> >8 inch diameter plastic barrel and place your three mics about 8
>
>> > >> >and 3/8 inches apart along the circumference. Or some other
>> > >> >"circular" form in place of the barrel. ...
>>
>>
>>
>>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/
>
>
>
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>
>
>
>
>
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