simple circuit design

I am looking for someone to prepare for me a fairly simple circuit
design with all components and values specified. I will be happy to
pay any reasonable amount for this service. what I want is
a device which will accept the audio input from a condenser
microphone, and pass it through a low-pass filter which will only pass
frequencies up to 12 Hz with a fairly sharp cut-off. The filtered
output should be fed into a device such as an LED array which will
approximately reflect the dominant frequency in the range 0 to 12.
Ideally, the voltage supply will be 6V.

If this is insufficient information, please get back to me.

Eddie

 

[mc]

<eddiecarron@btconnect.com> wrote in message
news:1182247697.671211.76400@g4g2000hsf.googlegroups.com...

I am looking for someone to prepare for me a fairly simple circuit
design with all components and values specified. I will be happy to
pay any reasonable amount for this service. what I want is
a device which will accept the audio input from a condenser
microphone, and pass it through a low-pass filter which will only pass
frequencies up to 12 Hz with a fairly sharp cut-off. The filtered
output should be fed into a device such as an LED array which will
approximately reflect the dominant frequency in the range 0 to 12.
Ideally, the voltage supply will be 6V.

If this is insufficient information, please get back to me.

Since this sounds like a Fourier transform, you may also want to post on
comp.arch.embedded.

My first worry would be that the condenser microphone doesn't have any
useful sensitivity at frequencies that low.

 

[legg]

On Tue, 19 Jun 2007 10:12:46 -0400, "mc"
<look@www.ai.uga.edu.for.address> wrote:

design with all components and values specified. I will be happy to
what I want is
a device which will accept the audio input from a condenser
microphone, and pass it through a low-pass filter which will only pass
frequencies up to 12 Hz with a fairly sharp cut-off. The filtered
output should be fed into a device such as an LED array which will
approximately reflect the dominant frequency in the range 0 to 12.
Ideally, the voltage supply will be 6V.

If this is insufficient information, please get back to me.

Since this sounds like a Fourier transform, you may also want to post on
comp.arch.embedded.

My first worry would be that the condenser microphone doesn't have any
useful sensitivity at frequencies that low.

Especially at the low end, 0Hz.

Actually, at those frequencies, you might just be satisfied with
counting the blinks.

RL

 

[Bob Woodward]

legg wrote:

On Tue, 19 Jun 2007 10:12:46 -0400, "mc"
look@www.ai.uga.edu.for.address> wrote:

design with all components and values specified. I will be happy to
what I want is
a device which will accept the audio input from a condenser
microphone, and pass it through a low-pass filter which will only pass
frequencies up to 12 Hz with a fairly sharp cut-off. The filtered
output should be fed into a device such as an LED array which will
approximately reflect the dominant frequency in the range 0 to 12.
Ideally, the voltage supply will be 6V.

If this is insufficient information, please get back to me.
Since this sounds like a Fourier transform, you may also want to post on
comp.arch.embedded.

My first worry would be that the condenser microphone doesn't have any
useful sensitivity at frequencies that low.


Especially at the low end, 0Hz.

Actually, at those frequencies, you might just be satisfied with
counting the blinks.

RL

There are microphones that are perfectly capable of picking-up
frequencies as low as 0.1 Hz
They are available, sold as measuring microphones.
When your budget is not sufficient, a more
conventional microphone can be modified to do so.
This microphone needs to be a omni-directional type condensor mic.
These are pressure-sensitive microphones.
Electronics needs to be modified for DC-coupling.
And when modifying, the low-pas can be done at-once.

But please be aware that this conventional microphone will still
be a studio-quality type costing $ 1000.- or more

Bob

 

[Eeyore]

mc wrote:

My first worry would be that the condenser microphone doesn't have any
useful sensitivity at frequencies that low.

Agreed.

Graham