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]

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.

 

[L.A.T.]

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.

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.

 

[David L. Jones]

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.

 

[L.A.T.]

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.

 

[L.A.T.]

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]

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.

 

[L.A.T.]

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