microphone filters

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smkymicpot

New Member

• Mar 5, 2009

• #1

Hi can anyone help me?

I am looking for microphone filters which will filter out souds of close frequencies ( in and around 250 to 500 hz apart).
so i can play a note of frequency 261 and a note of frequency 400 and the output of the microphone will cause different output voltages?

 

Nigel Goodwin

Super Moderator

Most Helpful Member

• Mar 5, 2009

• #2

So you're looking for a frequency to voltage converter?.

As always with these kind of vague requests, you would do a LOT better telling us EXACTLY what you're trying to do (and why).

 

Last edited: Mar 5, 2009

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smkymicpot

New Member

• Mar 8, 2009

• #3

Ok the exact project i am working on is a car which when detects a frequency which i choose, using the microphone filter, causes the car to move forward and when a different frequency is detected, one that i have also chosen, the car will begin to move backwards. the frequencies must be close together as i had intended to be able to control the car by my voice. is it possible to get filters cheaply which will do this? I couldnt find much on filters and am not even sure where to look.

 

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flat5

Member

• Mar 8, 2009

• #4

Why a microphone? You can use dual tone encoders and decoders.

 

duffy

Well-Known Member

• Mar 8, 2009

• #5

He said voice.

smkymicpot - check out an LM567 phase-locked-loop. It detects a particular frequency, you would use 2 of them, one for 261hz and the other for the 400hz signal.

 

audioguru

Well-Known Member

Most Helpful Member

• Mar 8, 2009

• #6

I am not a singer but I tried singing as high as I can. 305Hz. If I am kicked between my legs then I might scream as high as 350Hz.
There is no way that I can sing as high as 400Hz. Some "guy" singers can.

 

duffy

Well-Known Member

• Mar 8, 2009

• #7

No, but you can whistle that high. First time I saw a system like this it was in a robotics book by Frank Dacosta, he was whistling in binary.

 

audioguru

Well-Known Member

Most Helpful Member

• Mar 8, 2009

• #8

I studied music every day at home and in school. I almost got "perfect pitch" where a person can identify a frequency like color is to vision. Not anymore.

 

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smkymicpot

New Member

• Mar 11, 2009

• #9

Thanks duffy I think thatl work cheers 4 d help!!!

 

duffy

Well-Known Member

• Mar 11, 2009

• #10

Sure. If you can find a copy of _How to Build Your Own Working Robot Pet_ by Frank DaCosta, it has circuits and code that might be helpful on that.