Luminous response for a determined frequency

[luixclid]

Hello Forum,

I'm a newbie and i looking for some advice to start this project.

I need to light a 12v light when a sound is heared. The frequency must be between 10khz and 50khz.

I suppose i need to make a mic amplifier with some frequency filters and a power section on the end to light up, but i'm concerned about wich amp IC and/or transistors to use.

Please i will be soooo grateful for all your help

Luix
____________________
Maybe I'm Undecided... Maybe not

 

[Analog]

Probably three stages. First, amplify the input to a reasonable level. Bandpass filter, then drive a mosfet or bjt to the load. As far as frequency response goes, the unity gain bandwidth of most modern opamps will suffice for your range, as long as you don't ask one stage to do all the amplification. Even a basic 741 staged circuit could do this easily, and its UGBWP~1MHz.

 

[audioguru]

What are you going to use for a microphone?
The max frequency for audio microphones is somewhere between 15kHz and 25kHz.
Ultrasonic transducers work at about 40kHz with a sharp resonance. I don't know of a mic that is sensitive from 25kHz to 40kHz and from 40kHz to 50kHz.

Ordinary TL071 single, TL072 dual and TL074 quad opamps amplify very well up to 100kHz. An old 741 opamp has a max frequency of only 9kHz at full output swing.

 

[luixclid]

Ooops!

I think i made a mistake about the frequencies, the range i try to catch is a sound that humans can hear, more in the range of high pitch sounds.
Maybe this be more clear.

About the amps, do i need to put severals amps in a chain to make this work? (I'm sorry but I'm really a newbie)

Thanks Analog, Thanks Audioguru, i'ts good to have a mentor...

Luix
____________________
Maybe I'm Undecided... Maybe not

 

[audioguru]

Any microphone will pickup 10kHz to 20kHz which are high audio frequencies.
What makes the high frequency sound?
The total gain will need to be about 300 so use two stages with an opanp in each stage, a gain of 20 followed by a stage with a gain of 15.

 

[luixclid]

Thanks again Audioguru,

I have a little deaf friend, who likes to buy icecream from a vending truck, i would like to make him "see" the sound the truck made.

About the sound, i'ts like a siren or a high pitch, short beeps horn.

May i use some "standard" configuration for TL072 and duplicate it in every amp?

I'm already have a 12v power supply, what's te best to put in the end in order to light for example, a little car bulb? or better, a bunch of leds?

Luix
____________________
Maybe I'm Undecided... Maybe not

 

[audioguru]

The light will go off each time a bird chirps, or when any other high pitched sound occurs.

 

[luixclid]

I know,

But i think, the truck sound is louder than almost everything, so i'm thinking in triggering the light depending on that.

Also, i think the sequence of the light on the device probably make him differ the siren sound from less constant others (i mean, the siren is like more a "--- --- --- --- ---" sound).

Luix
____________________
Maybe I'm Undecided... Maybe not

 

[audioguru]

Loud "--- --- --- --- ---" sounds:
Fire trucks, ambulances, screeching worn brakes, jet airplanes and that ice cream vendor.

 

[luixclid]

LoL,

But, i still think is a good idea, remember that a boy will run at the window to be sure...

Luix
____________________
Maybe I'm Undecided... Maybe not

 

[audioguru]

LoL,

But, i still think is a good idea, remember that a boy will run at the window to be sure...

The boy will run to the window many times to the false alarms for a couple of days then never again.

 

[luixclid]

ok, i give up

there is a way to tunning, to the specific sound?

Luix
____________________
Maybe I'm Undecided... Maybe not

 

[audioguru]

there is a way to tunning, to the specific sound?

The sound is the same as many other loud, high pitched repetitive sounds.
Our hearing and brain identifies a sound by its envelope, harmonics and pattern in addition to the simple things.

 

[luixclid]

As i said...
I give up.

But, anyway, i would like to try it

i'm still lost with this questions:

May i use some "standard" configuration for TL072 and duplicate it in every amp?

I'm already have a 12v power supply, what's te best to put in the end in order to light for example, a little car bulb? or better, a bunch of leds?



Please, i'm very interested in how to make this project, i learned electronics, but was 20 years ago.

I learned a little about op amps then, but i barely remember.

This is my first project since then, so, every help will be grateful.



Luix
____________________
Maybe I'm Undecided... Maybe not

 

[audioguru]

You need a dual stage preamp, a highpass filter or two then a rectifier, filter and light driver. It is a fairly complicated project for something that probably won't work.

 

[Roff]

As i said...
I give up.

But, anyway, i would like to try it

i'm still lost with this questions:

May i use some "standard" configuration for TL072 and duplicate it in every amp?

I'm already have a 12v power supply, what's te best to put in the end in order to light for example, a little car bulb? or better, a bunch of leds?



Please, i'm very interested in how to make this project, i learned electronics, but was 20 years ago.

I learned a little about op amps then, but i barely remember.

This is my first project since then, so, every help will be grateful.



Luix
____________________
Maybe I'm Undecided... Maybe not

How much current will your 12 volt supply provide? That may restrict what kind of light(s) you use.
Do you have a microphone? If so, what kind? I'm trying to design something for you, and these are the unknowns, plus one other: The frequency of the truck's "siren". Any idea? The bandpass filter has to be designed to accommodate it.

 

[luixclid]

Hi Ron,

Thanks for the help

The power supply have 800ma output, i don't have microphone yet.

About the siren frequency, i can't tell exactly, but if the filter(s) have some regulations i will be able to adjust to the correct freq.


Luix
____________________
Maybe I'm Undecided... Maybe not

 

[Roff]

Unless one of the other guys knows how to make a simple tunable audio-range bandpass filter, this project is going to get pretty complicated. i know a few of ways to do it, but none of them are simple.

 

[Sig239]

Hello all,
Perhaps you could record a sample of the truck while it goes by, then input it thru your soundcard to get a frequency (with the help of some software of course). If you don't dont have the software, you could just send me the sound clip and I would extract the info for you.

 

[audioguru]

The ice cream truck on my street doesn't go fast, but I can hear the Doppler shift in the pitch of its song as it is coming then as it has gone by.
The same thing happens to the "knife sharpenning" truck's bell.

You might only detect the tuned frequency if the truck stops to serve a neighbour.