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### Topic: Measuring frequency of air column (open ended and closed) (Read 120 times)previous topic - next topic

#### wonderfuliot

##### Apr 26, 2018, 06:48 amLast Edit: Apr 26, 2018, 06:50 am by wonderfuliot
Hi,

Is there any way of measuring the frequency of air column using arduino and speaker?

Resonance frequency of open ended (one side open and one side closed) and close ended pipes (both ends closed) both need to be measured.
Can we infer the resonance frequency by measuring the impedance of a noise excited speaker?

Thanks and Regards,
WI

#### Koepel

#1
##### Apr 26, 2018, 04:12 pm
The basic Arduino boards are very bad with sound. Making a sine wave is already a major task for an Arduino Uno.

There are sound libraries for the Due and the Arduino Zero and M0, but that is just a small start.
The Teensy boards have more possibilities for sound.

My suggestion is to use a Raspberry Pi, that is a computer and you have all the linux tools that you want.
Perhaps there is an app for Android, but I doubt it.

I don't know if measuring the impedance of the speaker will work. The speaker itself has resonance peaks (both in sound and impedance). I think you need a measurement microphone.

Using noise is a step further than a speaker and a measurement microphone. You can test the theory, but in practice it might be a step too far.

#### wvmarle

#2
##### Apr 26, 2018, 04:32 pm
To find the resonance frequency you may do a sweep (use a tone generator that can be controlled by an Arduino), and place a microphone on the other side, measuring the volume (an Arduino can handle this quiet well - provided your microphone can output a proper signal, probably through amplifier). Resonance is the frequency where the volume is highest.
Quality of answers is related to the quality of questions. Good questions will get good answers. Useless answers are a sign of a poor question.

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