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Topic: Sensor for sound frequency detection (Read 154 times) previous topic - next topic

sperr0w

May 27, 2015, 09:07 am Last Edit: May 27, 2015, 10:08 am by sperr0w
Hello!

I'm new in Arduino and I have some question.

I need to create sound frequency meter, but I dont know how to start.

Actially my theme s connected to http://forum.arduino.cc/index.php?topic=13906.0

I find info that sensor KY-038 exists, that have microphone and analog and digital output.
AO, analog output, real-time output voltage signal of the microphone
DO, when the sound intensity reaches a certain threshold, the output high and low signal

Is it possible to get scalar sound frequency from this sensor ( like 200Hz, 240Hz). I need to determine sound frequency only in interval between 150 and 350 Hz.

If it is not possible to get sound frequency data from KY-038, tell me please, what sensor do I need to buy?

I also find sound recognition module, may be I need to use it instead of KY-038?

Please, give me some start point?

sperr0w

I find also Audio analyzer from DFRobot based on MSGEQ7. May be I can use it to get frequency?

DrDiettrich

I don't think that you can get a filter module matching your needs. Build your own frequency counter if you want to measure/distinguish exact frequencies,

sperr0w

Y just want my module to show me frequency of sound, that go to the sensor. I expected that this is a trivial task...

DrDiettrich

Y just want my module to show me frequency of sound, that go to the sensor. I expected that this is a trivial task...
It isn't trivial at all :-(

SurferTim

If you are not against using an external device, you might want to take a look at the LM567 tone decoder.
http://www.ti.com/lit/ds/symlink/lm567c.pdf
It will provide a digital lock signal and an analog offset from center frequency, so it will require two pins, one digital and one analog.

sperr0w

Thanks, it seems that this is a step in right direction.

May be you also can give me some examples of using LM567 ?
Actially there is a Microphone with LM567 presented:

http://aliexpress.com/store/product/Voice-activated-switch-module-sound-sensor-voice-module-fitted-frequency-voice-activated-lm567-module/414242_1115173284.html

I Cant understand now, how can I use this LM567?

SurferTim

The LM567 is a phase locked loop device. It has a digital output that signals a frequency in range, and a cap filtered PLL speed control. That is the pin you monitor to determine the frequency offset from center frequency. I'm not where I can get a schematic, but I'll try to get to it later.

Archibald

#8
May 27, 2015, 06:04 pm Last Edit: May 27, 2015, 09:03 pm by Archibald
I need to determine sound frequency only in interval between 150 and 350 Hz.
Am I missing something here?

If that is fairly close to being a pure sine wave sound, can't you feed the signal (after a microphone preamplifier) into an analogue input of your Arduino and time when it is positive and negative?

If the Arduino is not fast enough with other tasks, put the amplified signal into a voltage comparator to give a square wave and put that into a counter integrated circuit to divide by say 16.

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