Arduino

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Measure sound pressure level and spectrum analyzer with FHT using Arduino and module sensor MAX4466
Nguyen Duy Quang, Nguyen Dinh Nguyen, Dang Thanh Tin
1 Faculty of Electrical & Electronics Engineering, Bach Khoa University, Ho Chi Minh City, Vietnam
2 Faculty of Electrical & Electronics Engineering, Bach Khoa University, Ho Chi Minh City, Vietnam

Abstract— By measuring sound levels, we can tell where a quiet enough or a place is contaminated by noise. Then, designers offer soundproofing solutions suitable for each location such as home or library,…
Keywords— measure sound levels, arduino, max4466
I. INTRODUCTION
Today, sound pollution is one of the social problems[1]. It significantly reduces the concentration of an individual or a …show more content…

Also, if the sensor is a pure mic then when the noise level changes but the voltage measured from analog pins of Arduino is not change because with ADC, assume that reference 5V it needs 5/1024 = 4.8mV to inscrease 1. Therefore, the small analog signal (such as the tranquilizers) must pass through the amplifier and then the Arduino reads the voltage on the amplifier. Conversely, for loud tones can cause sampling to be useless because the reading signal is always at 5V (1023), it is important to neutralize the gain factor to measure.

B. Module MAX4466 ?
This module is well suited for audio changer, recording, sampling and audio-reactive projects that use FFT. It has a small pot at the back of the module for gain adjustment from 25 to 125
Using this module is also very simple, GND pin for ground, Vcc for 2.4-5VDC. For Arduino types such as NANO or UNO R3, the 3.3V source is the most stable, least disturbed source, so we will use this source instead of the 5V source. The output signal will be Vcc / 2 when it is complete-ly quiet..
On this module, we have a range of values from 0 to 1023. It’s mean the voltage fluctuate from – MAX to MAX. So 512 mean “0” in …show more content…

Firstly, our microphone is not sensi-tive to all frequencies, it is still quite pure, we need filter the noise first manually. Secondly, it is extremely hard to re-produce sound signals at all frequencies exactly the same level, it depend more on the quality of speaker. High-end products will overcome this situation to measure the dB value accurately. Thirdly, because the human ear is not sensitive equally to differences frequency, there’s one unit apply different weights to different frequency dBA (A-weighting) and it is used for professional devices

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