How to get 1.5Volts from a microphone.

[L.A.T.]

I have cobbled together several devices for triggering remote cameras, based
on a Passive Infrared Receiver.
Briefly, the PIR, which is designed to sense a passer-by and turn on six
white LEDs for a few seconds to illuminate a stairway or whatever, has one
of the LEDs replaced with a connection to an analogue-to-digital input of a
Picaxe. The Picaxe program waits until the passer-by (in this case a wild
lyrebird singing and displaying on his performance mound ) triggers the PIR
and takes photographs every five seconds for one minute. After the minute,
the Picaxe program tries again, the assumption being that if the bird is
still performing, the PIR will pick him up again.
Not so. What happens is that the bird stands stock still for up to twenty
minutes and doesn't trigger the PIR again until he leaves. Our only
photographic record of his memorabloe performance is the first minute after
he arrives, and a brief shot of his retreating backside as he leaves.
But all the time he is there he is singing, and deafeningly. So what I need
is a signal from a microphone. I have programmed the Picaxe to recognise a
level, however fleeting, of 1.5Volts from the PIR, and I'd like to add to
the existing setup a similar, ~1.5Volts from a microphone. Just a voltage.
No attempt to reproduce the actual sound. I would need some kind of level
control, in order to adjust the output to respond to the target bird's
close-up song and not respond to his rivals who are some distance away and
nowhere near as loud.
I have looked at a kit for a voice-controlled microphone which would
probably work but needs 12Volts worth of batteries. I need at least four of
these devices and possibly eight, so they must be cheap. I feel that there
must be a simple way to achieve this. On past experience, if there is a
simple answer, this is the newsgroup where I will find it.
Can anyone help?

 

[David L. Jones]

L.A.T. wrote:

I have cobbled together several devices for triggering remote
cameras, based on a Passive Infrared Receiver.
Briefly, the PIR, which is designed to sense a passer-by and turn on
six white LEDs for a few seconds to illuminate a stairway or
whatever, has one of the LEDs replaced with a connection to an
analogue-to-digital input of a Picaxe. The Picaxe program waits until
the passer-by (in this case a wild lyrebird singing and displaying on
his performance mound ) triggers the PIR and takes photographs every
five seconds for one minute. After the minute, the Picaxe program
tries again, the assumption being that if the bird is still
performing, the PIR will pick him up again. Not so. What happens is that
the bird stands stock still for up to
twenty minutes and doesn't trigger the PIR again until he leaves. Our
only photographic record of his memorabloe performance is the first
minute after he arrives, and a brief shot of his retreating backside
as he leaves.

Why not just have to camera trigger for 20 minutes instead of 1 minute then?
Storage is cheap...

But all the time he is there he is singing, and deafeningly. So what
I need is a signal from a microphone. I have programmed the Picaxe
to recognise a level, however fleeting, of 1.5Volts from the PIR, and
I'd like to add to the existing setup a similar, ~1.5Volts from a
microphone. Just a voltage. No attempt to reproduce the actual sound.
I would need some kind of level control, in order to adjust the
output to respond to the target bird's close-up song and not respond
to his rivals who are some distance away and nowhere near as loud.
I have looked at a kit for a voice-controlled microphone which would
probably work but needs 12Volts worth of batteries. I need at least
four of these devices and possibly eight, so they must be cheap. I
feel that there must be a simple way to achieve this. On past
experience, if there is a simple answer, this is the newsgroup where
I will find it. Can anyone help?

You'll have to experiment a bit and figure out what levels you get out of
your electret mic, and what the background levels are.
That will require some form of data logging capture of the actual audio
levels (or waveforms) so you'll have some reference levels to work from for
your final solution. That starts getting a bit messy and potentially
unreliable I suspect. This solution doesn't give good vibes...
You might get better background sound discrimination with a directional
shotgun mic.

I'd just shoot images for longer using your existing setup and sort through
the images later.

Silly question, but if you want to capture the bird "performing", wouldn't a
video camera be a better option?
i.e. if the bird is just sitting their "stock still" as you say (singing?),
what's the point getting that on still camera?

Dave.
--
---------------------------------------------
Check out my Electronics Engineering Video Blog & Podcast:
http://www.alternatezone.com/eevblog/

 

[L.A.T.]

"David L. Jones" <altzone@gmail.com> wrote in message
news:X6j1m.871$0T2.738@newsfe24.iad...

L.A.T. wrote:
I have cobbled together several devices for triggering remote
cameras, based on a Passive Infrared Receiver.
Briefly, the PIR, which is designed to sense a passer-by and turn on
six white LEDs for a few seconds to illuminate a stairway or
whatever, has one of the LEDs replaced with a connection to an
analogue-to-digital input of a Picaxe. The Picaxe program waits until
the passer-by (in this case a wild lyrebird singing and displaying on
his performance mound ) triggers the PIR and takes photographs every
five seconds for one minute. After the minute, the Picaxe program
tries again, the assumption being that if the bird is still
performing, the PIR will pick him up again. Not so. What happens is that
the bird stands stock still for up to
twenty minutes and doesn't trigger the PIR again until he leaves. Our
only photographic record of his memorabloe performance is the first
minute after he arrives, and a brief shot of his retreating backside
as he leaves.

Why not just have to camera trigger for 20 minutes instead of 1 minute
then?
.................. He can come for a couple of minutes or for up to twenty.

...................The warmth of the sun reflecting off the clay, interrupted
by moving branches, gives two or three false triggers each session.
...................The camera batteries will last for up to seven hours while
waiting, but will run out after less than an hour and a half of shooting.

Storage is cheap...
..................The cameras' CF cards are limited to 2Gig.

But all the time he is there he is singing, and deafeningly. So what
I need is a signal from a microphone. I have programmed the Picaxe
to recognise a level, however fleeting, of 1.5Volts from the PIR, and
I'd like to add to the existing setup a similar, ~1.5Volts from a
microphone. Just a voltage. No attempt to reproduce the actual sound.
I would need some kind of level control, in order to adjust the
output to respond to the target bird's close-up song and not respond
to his rivals who are some distance away and nowhere near as loud.
I have looked at a kit for a voice-controlled microphone which would
probably work but needs 12Volts worth of batteries. I need at least
four of these devices and possibly eight, so they must be cheap. I
feel that there must be a simple way to achieve this. On past
experience, if there is a simple answer, this is the newsgroup where
I will find it. Can anyone help?

You'll have to experiment a bit and figure out what levels you get out of
your electret mic, and what the background levels are.
That will require some form of data logging capture of the actual audio
levels (or waveforms) so you'll have some reference levels to work from
for your final solution. That starts getting a bit messy and potentially
unreliable I suspect. This solution doesn't give good vibes...
You might get better background sound discrimination with a directional
shotgun mic.
............................The Mics will be directional.
I'd just shoot images for longer using your existing setup and sort
through the images later.
...........................On any given day, we will have six to eight mounds

staked out.
............................On most days he won't perform where we want him.

Silly question, but if you want to capture the bird "performing", wouldn't
a video camera be a better option?
........................We have eight Canon G2 cameras. Most were bought on

eBay for about $150 each. Video cameras are too expensive. (YET. Maybe in a
year or so).

i.e. if the bird is just sitting their "stock still" as you say
(singing?), what's the point getting that on still camera?
.................. Sorry, a bit of hyperbole there. He is displaying his

amazing tail feathers in a most photogenic series of poses.
...................His warm, infrared-emitting body is not moving enough to
affect the PIR.

Dave.
--
---------------------------------------------
Check out my Electronics Engineering Video Blog & Podcast:
http://www.alternatezone.com/eevblog/

 

[Mark Harriss]

You could always a microwave or ultrasonic doppler sensor instead of
a PIR, alternatively the better quality PIR's had different Fresnel lenses
for the front for different applications: longer range/better gain.

It may well be that a really cheap PIR is better suited as it won't
tune out the lyrebird as background noise.

 

[Bruce Varley]

"L.A.T." <tt92@ispdr.net.au> wrote in message
news:VMi1m.1063$ze1.707@news-server.bigpond.net.au...

I have cobbled together several devices for triggering remote cameras,
based on a Passive Infrared Receiver.
Briefly, the PIR, which is designed to sense a passer-by and turn on six
white LEDs for a few seconds to illuminate a stairway or whatever, has one
of the LEDs replaced with a connection to an analogue-to-digital input of
a Picaxe. The Picaxe program waits until the passer-by (in this case a
wild lyrebird singing and displaying on his performance mound ) triggers
the PIR and takes photographs every five seconds for one minute. After the
minute, the Picaxe program tries again, the assumption being that if the
bird is still performing, the PIR will pick him up again.
Not so. What happens is that the bird stands stock still for up to twenty
minutes and doesn't trigger the PIR again until he leaves. Our only
photographic record of his memorabloe performance is the first minute
after he arrives, and a brief shot of his retreating backside as he
leaves.
But all the time he is there he is singing, and deafeningly. So what I
need is a signal from a microphone. I have programmed the Picaxe to
recognise a level, however fleeting, of 1.5Volts from the PIR, and I'd
like to add to the existing setup a similar, ~1.5Volts from a microphone.
Just a voltage. No attempt to reproduce the actual sound. I would need
some kind of level control, in order to adjust the output to respond to
the target bird's close-up song and not respond to his rivals who are some
distance away and nowhere near as loud.
I have looked at a kit for a voice-controlled microphone which would
probably work but needs 12Volts worth of batteries. I need at least four
of these devices and possibly eight, so they must be cheap. I feel that
there must be a simple way to achieve this. On past experience, if there
is a simple answer, this is the newsgroup where I will find it.
Can anyone help?

Using sound detection here is an interesting problem that I've dealt with

several times in other scenarios. Just measuring level is likely to result
in a spurious trigger rate that's far too high if the setup is sensitive
enough to detect anything. I'd be considering some processing of the sound
input, as far as I know, Lyre bird song can contain single frequency sounds,
it's easy to pick this with a small microprocessor these days, with fast
fourier processing. It would require someone with micro programming skills,
however there's tons of FFT code googleable. Bird song whistle will show as
a clear spike in a data array that will stand out from typical background
noise in a bush environment, which will be mostly white noise or close to
it. You wouldn't need to know the frequency, just that there was one or a
few isolated frequencies present which are significantly above the
background.

I'd get a recording of the sort of thing you expect, and use that to test
the algorithm.

Sorry if that all sounds high-tech, but I believe it could be a viable
solution.

 

[ian field]

"L.A.T." <tt92@ispdr.net.au> wrote in message
news:VMi1m.1063$ze1.707@news-server.bigpond.net.au...

I have cobbled together several devices for triggering remote cameras,
based on a Passive Infrared Receiver.
Briefly, the PIR, which is designed to sense a passer-by and turn on six
white LEDs for a few seconds to illuminate a stairway or whatever, has one
of the LEDs replaced with a connection to an analogue-to-digital input of
a Picaxe. The Picaxe program waits until the passer-by (in this case a
wild lyrebird singing and displaying on his performance mound ) triggers
the PIR and takes photographs every five seconds for one minute. After the
minute, the Picaxe program tries again, the assumption being that if the
bird is still performing, the PIR will pick him up again.
Not so. What happens is that the bird stands stock still for up to twenty
minutes and doesn't trigger the PIR again until he leaves. Our only
photographic record of his memorabloe performance is the first minute
after he arrives, and a brief shot of his retreating backside as he
leaves.
But all the time he is there he is singing, and deafeningly. So what I
need is a signal from a microphone. I have programmed the Picaxe to
recognise a level, however fleeting, of 1.5Volts from the PIR, and I'd
like to add to the existing setup a similar, ~1.5Volts from a microphone.
Just a voltage. No attempt to reproduce the actual sound. I would need
some kind of level control, in order to adjust the output to respond to
the target bird's close-up song and not respond to his rivals who are some
distance away and nowhere near as loud.

You can get a pretty large output from an electret by using a TL431 in its
linear mode, its often referred to as a programmable or adjustable zener but
is actually a comparator with built in 2.5V reference - in a TO92 package.

If you give the TL431 large negative feedback it will amplify like an op-amp
and once the operating point has been stabilised the control input is
maintained at 2.5V which suits most electrets perfectly.

The main problem is that the large amount of nfb required results in low
gain - this problem is solved by tapping the feedback resistor and AC
shunting the tap with an electrolytic.

Start with a 2k2 resistor from cathode (of the TL431) to Vcc and connect
your electret from control input to GND. Now connect a 100k pot from cathode
to control input and adjust the volt drop across the 2k2 - the minimum
voltage on the cathode is 2.5V so subtract that before calculating 1/2 Vcc,
the resistance should come out somewhere near 47k. To tap the nfb resistor
connect 1k2 to the cathode, the select on test resistor goes from the 1k2 to
the control input/electret + and the electrolytic goes from the tap between
the 2 resistors and GND.

This arrangement kills the AC nfb without affecting the DC nfb which runs
the comparator in linear mode and sets the operating point.

The AC gain will probably be far more than you need, it can be tamed by
inserting a pot in series with the electrolytic, about 470 should give
enough adjustment.

Its not HiFi but if all you need is a sound activated trigger it should be
perfect.

 

[David L. Jones]

L.A.T. wrote:

I have cobbled together several devices for triggering remote
cameras, based on a Passive Infrared Receiver.
Briefly, the PIR, which is designed to sense a passer-by and turn on
six white LEDs for a few seconds to illuminate a stairway or
whatever, has one of the LEDs replaced with a connection to an
analogue-to-digital input of a Picaxe. The Picaxe program waits until
the passer-by (in this case a wild lyrebird singing and displaying on
his performance mound ) triggers the PIR and takes photographs every
five seconds for one minute. After the minute, the Picaxe program
tries again, the assumption being that if the bird is still
performing, the PIR will pick him up again. Not so. What happens is that
the bird stands stock still for up to
twenty minutes and doesn't trigger the PIR again until he leaves. Our
only photographic record of his memorabloe performance is the first
minute after he arrives, and a brief shot of his retreating backside
as he leaves. But all the time he is there he is singing, and deafeningly.
So what
I need is a signal from a microphone. I have programmed the Picaxe
to recognise a level, however fleeting, of 1.5Volts from the PIR, and
I'd like to add to the existing setup a similar, ~1.5Volts from a
microphone. Just a voltage. No attempt to reproduce the actual sound.
I would need some kind of level control, in order to adjust the
output to respond to the target bird's close-up song and not respond
to his rivals who are some distance away and nowhere near as loud.
I have looked at a kit for a voice-controlled microphone which would
probably work but needs 12Volts worth of batteries. I need at least
four of these devices and possibly eight, so they must be cheap. I
feel that there must be a simple way to achieve this. On past
experience, if there is a simple answer, this is the newsgroup where
I will find it. Can anyone help?

Have you tried motion dection using using the camera?
http://chdk.wikia.com/wiki/CHDK

Dave.

--
================================================
Check out my Electronics Engineering Video Blog & Podcast:
http://www.alternatezone.com/eevblog/

 

[L.A.T.]

"David L. Jones" <altzone@gmail.com> wrote in message
newswV1m.876$Ei4.436@newsfe13.iad...
snip>

Have you tried motion dection using using the camera?
http://chdk.wikia.com/wiki/CHDK

Dave.
.....................Alas, this so0ftware works on Canon G7 and G9.

.....................Our cameras are Canon G2, which are seven? years old.
......................When we were capturing images to laptops. we used
ZoneAlarm, with limited success.

================================================
Check out my Electronics Engineering Video Blog & Podcast:
http://www.alternatezone.com/eevblog/

 

[David Eather]

Mark Harriss wrote:

You could always a microwave or ultrasonic doppler sensor instead of a
PIR, alternatively the better quality PIR's had different Fresnel lenses
for the front for different applications: longer range/better gain.

It may well be that a really cheap PIR is better suited as it won't
tune out the lyrebird as background noise.

No matter what quality of lens the PIR only triggers if there is
movement - then bird standing still and singing won't qualify.

 

[David Eather]

Bruce Varley wrote:

"L.A.T." <tt92@ispdr.net.au> wrote in message
news:VMi1m.1063$ze1.707@news-server.bigpond.net.au...
I have cobbled together several devices for triggering remote cameras,
based on a Passive Infrared Receiver.
Briefly, the PIR, which is designed to sense a passer-by and turn on six
white LEDs for a few seconds to illuminate a stairway or whatever, has one
of the LEDs replaced with a connection to an analogue-to-digital input of
a Picaxe. The Picaxe program waits until the passer-by (in this case a
wild lyrebird singing and displaying on his performance mound ) triggers
the PIR and takes photographs every five seconds for one minute. After the
minute, the Picaxe program tries again, the assumption being that if the
bird is still performing, the PIR will pick him up again.
Not so. What happens is that the bird stands stock still for up to twenty
minutes and doesn't trigger the PIR again until he leaves. Our only
photographic record of his memorabloe performance is the first minute
after he arrives, and a brief shot of his retreating backside as he
leaves.
But all the time he is there he is singing, and deafeningly. So what I
need is a signal from a microphone. I have programmed the Picaxe to
recognise a level, however fleeting, of 1.5Volts from the PIR, and I'd
like to add to the existing setup a similar, ~1.5Volts from a microphone.
Just a voltage. No attempt to reproduce the actual sound. I would need
some kind of level control, in order to adjust the output to respond to
the target bird's close-up song and not respond to his rivals who are some
distance away and nowhere near as loud.
I have looked at a kit for a voice-controlled microphone which would
probably work but needs 12Volts worth of batteries. I need at least four
of these devices and possibly eight, so they must be cheap. I feel that
there must be a simple way to achieve this. On past experience, if there
is a simple answer, this is the newsgroup where I will find it.
Can anyone help?

Using sound detection here is an interesting problem that I've dealt with
several times in other scenarios. Just measuring level is likely to result
in a spurious trigger rate that's far too high if the setup is sensitive
enough to detect anything. I'd be considering some processing of the sound
input, as far as I know, Lyre bird song can contain single frequency sounds,
it's easy to pick this with a small microprocessor these days, with fast
fourier processing. It would require someone with micro programming skills,
however there's tons of FFT code googleable. Bird song whistle will show as
a clear spike in a data array that will stand out from typical background
noise in a bush environment, which will be mostly white noise or close to
it. You wouldn't need to know the frequency, just that there was one or a
few isolated frequencies present which are significantly above the
background.

I'd get a recording of the sort of thing you expect, and use that to test
the algorithm.

Sorry if that all sounds high-tech, but I believe it could be a viable
solution.

How about a notch filter tuned to the bird's frequency? - simple, cheap
and plenty of info on how available on the net.

 

[Michael A. Terrell]

David Eather wrote:

Mark Harriss wrote:


You could always a microwave or ultrasonic doppler sensor instead of a
PIR, alternatively the better quality PIR's had different Fresnel lenses
for the front for different applications: longer range/better gain.

It may well be that a really cheap PIR is better suited as it won't
tune out the lyrebird as background noise.

No matter what quality of lens the PIR only triggers if there is
movement - then bird standing still and singing won't qualify.

How about one of the rare tap dancing birds? ;-)


--
You can't have a sense of humor, if you have no sense!

 

[Mark Harriss]

David Eather wrote:

Mark Harriss wrote:


You could always a microwave or ultrasonic doppler sensor instead of
a PIR, alternatively the better quality PIR's had different Fresnel
lenses
for the front for different applications: longer range/better gain.

It may well be that a really cheap PIR is better suited as it won't
tune out the lyrebird as background noise.

No matter what quality of lens the PIR only triggers if there is
movement - then bird standing still and singing won't qualify.

A PIR Fresnel lens assembly is comprised of smaller lenses, it's
possible to buy different types that trade off range with the amount
of movement detected: If you fitted a lens with many more smaller
lenses in it, the range suffers but it will now trigger with only
slight sideways movements as the IR light from the bird is focussed
onto the sensor by different parts of the array.

With the right lens the bird would have to be totally stock still
to avoid detection.

 

[ian field]

"L.A.T." <tt92@ispdr.net.au> wrote in message
news:VMi1m.1063$ze1.707@news-server.bigpond.net.au...

I have cobbled together several devices for triggering remote cameras,
based on a Passive Infrared Receiver.
Briefly, the PIR, which is designed to sense a passer-by and turn on six
white LEDs for a few seconds to illuminate a stairway or whatever, has one
of the LEDs replaced with a connection to an analogue-to-digital input of
a Picaxe. The Picaxe program waits until the passer-by (in this case a
wild lyrebird singing and displaying on his performance mound ) triggers
the PIR and takes photographs every five seconds for one minute. After the
minute, the Picaxe program tries again, the assumption being that if the
bird is still performing, the PIR will pick him up again.
Not so. What happens is that the bird stands stock still for up to twenty
minutes and doesn't trigger the PIR again until he leaves. Our only
photographic record of his memorabloe performance is the first minute
after he arrives, and a brief shot of his retreating backside as he
leaves.
But all the time he is there he is singing, and deafeningly. So what I
need is a signal from a microphone. I have programmed the Picaxe to
recognise a level, however fleeting, of 1.5Volts from the PIR, and I'd
like to add to the existing setup a similar, ~1.5Volts from a microphone.
Just a voltage. No attempt to reproduce the actual sound. I would need
some kind of level control, in order to adjust the output to respond to
the target bird's close-up song and not respond to his rivals who are some
distance away and nowhere near as loud.
I have looked at a kit for a voice-controlled microphone which would
probably work but needs 12Volts worth of batteries. I need at least four
of these devices and possibly eight, so they must be cheap. I feel that
there must be a simple way to achieve this. On past experience, if there
is a simple answer, this is the newsgroup where I will find it.
Can anyone help?

http://www.rev-ed.co.uk/docs/picaxe_sound.pdf

 

[L.A.T.]

"ian field" <gangprobing.alien@ntlworld.com> wrote in message
news:ENk8m.16586$f17.5621@newsfe02.ams2...

"L.A.T." <tt92@ispdr.net.au> wrote in message
news:VMi1m.1063$ze1.707@news-server.bigpond.net.au...
I have cobbled together several devices for triggering remote cameras,
based on a Passive Infrared Receiver.
Briefly, the PIR, which is designed to sense a passer-by and turn on six
white LEDs for a few seconds to illuminate a stairway or whatever, has
one of the LEDs replaced with a connection to an analogue-to-digital
input of a Picaxe. The Picaxe program waits until the passer-by (in this
case a wild lyrebird singing and displaying on his performance mound )
triggers the PIR and takes photographs every five seconds for one minute.
After the minute, the Picaxe program tries again, the assumption being
that if the bird is still performing, the PIR will pick him up again.
Not so. What happens is that the bird stands stock still for up to twenty
minutes and doesn't trigger the PIR again until he leaves. Our only
photographic record of his memorabloe performance is the first minute
after he arrives, and a brief shot of his retreating backside as he
leaves.
But all the time he is there he is singing, and deafeningly. So what I
need is a signal from a microphone. I have programmed the Picaxe to
recognise a level, however fleeting, of 1.5Volts from the PIR, and I'd
like to add to the existing setup a similar, ~1.5Volts from a microphone.
Just a voltage. No attempt to reproduce the actual sound. I would need
some kind of level control, in order to adjust the output to respond to
the target bird's close-up song and not respond to his rivals who are
some distance away and nowhere near as loud.
I have looked at a kit for a voice-controlled microphone which would
probably work but needs 12Volts worth of batteries. I need at least four
of these devices and possibly eight, so they must be cheap. I feel that
there must be a simple way to achieve this. On past experience, if there
is a simple answer, this is the newsgroup where I will find it.
Can anyone help?


http://www.rev-ed.co.uk/docs/picaxe_sound.pdf

Perfect, I think. Thank you. Out with the soldering iron.
If you are interested, here are some pictures we have so far.
http://sites.google.com/site/lyrebir...e/2009/upm2009

They are part of a diary, so some comments might be incomprehensible,
and the whole thing is being shifted from one hosting service to another, so
some of the links mightn't work yet.
And finally, of the two old farts pictured, one is a bearded old fart and
the other is a beardless old fart.
I am the clean-shaven old fart.

 

[F Murtz]

L.A.T. wrote:

"ian field" <gangprobing.alien@ntlworld.com> wrote in message
news:ENk8m.16586$f17.5621@newsfe02.ams2...
"L.A.T." <tt92@ispdr.net.au> wrote in message
news:VMi1m.1063$ze1.707@news-server.bigpond.net.au...
I have cobbled together several devices for triggering remote cameras,
based on a Passive Infrared Receiver.
Briefly, the PIR, which is designed to sense a passer-by and turn on six
white LEDs for a few seconds to illuminate a stairway or whatever, has
one of the LEDs replaced with a connection to an analogue-to-digital
input of a Picaxe. The Picaxe program waits until the passer-by (in this
case a wild lyrebird singing and displaying on his performance mound )
triggers the PIR and takes photographs every five seconds for one minute.
After the minute, the Picaxe program tries again, the assumption being
that if the bird is still performing, the PIR will pick him up again.
Not so. What happens is that the bird stands stock still for up to twenty
minutes and doesn't trigger the PIR again until he leaves. Our only
photographic record of his memorabloe performance is the first minute
after he arrives, and a brief shot of his retreating backside as he
leaves.
But all the time he is there he is singing, and deafeningly. So what I
need is a signal from a microphone. I have programmed the Picaxe to
recognise a level, however fleeting, of 1.5Volts from the PIR, and I'd
like to add to the existing setup a similar, ~1.5Volts from a microphone.
Just a voltage. No attempt to reproduce the actual sound. I would need
some kind of level control, in order to adjust the output to respond to
the target bird's close-up song and not respond to his rivals who are
some distance away and nowhere near as loud.
I have looked at a kit for a voice-controlled microphone which would
probably work but needs 12Volts worth of batteries. I need at least four
of these devices and possibly eight, so they must be cheap. I feel that
there must be a simple way to achieve this. On past experience, if there
is a simple answer, this is the newsgroup where I will find it.
Can anyone help?

http://www.rev-ed.co.uk/docs/picaxe_sound.pdf

Perfect, I think. Thank you. Out with the soldering iron.
If you are interested, here are some pictures we have so far.
http://sites.google.com/site/lyrebir...e/2009/upm2009

Does not seem to work.

They are part of a diary, so some comments might be incomprehensible,
and the whole thing is being shifted from one hosting service to another, so
some of the links mightn't work yet.
And finally, of the two old farts pictured, one is a bearded old fart and
the other is a beardless old fart.
I am the clean-shaven old fart.

 

[L.A.T.]

Snip
http://www.rev-ed.co.uk/docs/picaxe_sound.pdf

Perfect, I think. Thank you. Out with the soldering iron.
If you are interested, here are some pictures we have so far.
http://sites.google.com/site/lyrebir...e/2009/upm2009


Does not seem to work.
Strange. Some of the URL is missing.

I'll try again

http://sites.google.com/site/lyrebirdman/Home/2009/upm2009
>>