Arduino Sound Sensor

Introduction

Measuring sound is difficult due to its logarithmic nature. There are digital and analog measuring systems available. Digital are either pure on/off or they might give I2C data.

A good explenation about sensors is at https://www.atomic14.com/2020/09/12/esp32-audio-input

Digital Sound sensor

Simple sound sensor; output True or False.

Code 1. The simple

Tutorial page: https://arduinogetstarted.com/tutorials/arduino-sound-sensor

#define SENSOR_PIN 7

int lastState = HIGH;  // the previous state from the input pin
int currentState;      // the current reading from the input pin

void setup() {
  Serial.begin(9600);
  pinMode(SENSOR_PIN, INPUT);
}

void loop() {
  currentState = digitalRead(SENSOR_PIN);
  if (currentState){
     Serial.println( currentState );
  }else{
     Serial.print("Schii");
  }

}

Code 1

Turn on the one more LED if the sound is strong enough.

#include <FastLED.h>

#define SENSOR_PIN 7
#define NUM_LEDS 10
#define LED_PIN 5

int soundState = HIGH;  // the previous state from the input pin
int numLeds = 0;
CRGB leds[NUM_LEDS];


void setup() {
  Serial.begin(9600);
  pinMode(SENSOR_PIN, INPUT);
  FastLED.addLeds<WS2812B, LED_PIN, GRB>(leds, NUM_LEDS);
  FastLED.setBrightness(20);
}

void loop() {
  soundState = digitalRead(SENSOR_PIN);
  if (soundState){
    numLeds++;
  }

  for (int i=0; i<min( numLeds, NUM_LEDS); i++){
    leds[i] = CRGB::Green;
    FastLED.show();
  }

  if (soundState){
    Serial.println("");
     Serial.println( soundState );
  }else{
     Serial.print("Schii");
  }

}

Code 2

1. Turn all the LEDS to black in the SetUp()
2. Add delay when sound is noticed (not two LEDs turning on at the same time).
3. turn of the last led after a while.

Code 3: test

#include <FastLED.h>

// Arduino's pin connected to OUT pin of the sound sensor
#define SENSOR_PIN 7
#define NUM_LEDS 10
#define LED_PIN 5

int soundState = HIGH;  // the previous state from the input pin
int numLeds = 0;
CRGB leds[NUM_LEDS];
unsigned long turnOffStart;

void setup() {
  Serial.begin(9600);
  pinMode(SENSOR_PIN, INPUT);
  FastLED.addLeds<WS2812B, LED_PIN, GRB>(leds, NUM_LEDS);
  FastLED.setBrightness(20);
  for (int i=0; i<NUM_LEDS; i++){
    leds[i] = CRGB::Black;
    FastLED.show();
  }
  turnOffStart = millis();

}



void loop() {
  soundState = digitalRead(SENSOR_PIN);
  if (soundState){
    numLeds++;
    turnOffStart = millis();
    delay(50);

  }
  if (millis() - turnOffStart > 200){
    turnOffStart = millis();
    numLeds = max( 0, numLeds--);
  }

  for (int i = min( numLeds, NUM_LEDS); i<NUM_LEDS; i++){
    leds[i] = CRGB::Black;
    FastLED.show();
  } 

  for (int i=0; i<min( numLeds, NUM_LEDS); i++){
    leds[i] = CRGB::Green;
    FastLED.show();
  }

}

HQ: Gravity: Analog Sound Level Meter

https://www.dfrobot.com/product-1663.html and the Wiki https://wiki.dfrobot.com/Gravity__Analog_Sound_Level_Meter_SKU_SEN0232

MAX4466 / GY4466

MAX4466 Microphone Amplifier Module. Analog.

MAX9814

Introduction

• 

  Front view of the MAX9814 sensor.

• 

  The backside.

• 

  The values at somehow quiet room. The values are centered around 250.

Electret Microphone Amplifier - MAX9814 with Auto Gain Controller (AGC, built-in Automatic Gain Control) is a mic with integrated pre-amp plus audio amplifier. It is an analogic sensor.

Caption text

Pin	Arduino
Vdd	5 V	Power supply (2.7 V - 5.5 V)
GND	GND	GND
OUT	A0	Analog audio output
AR	No	Attack /release control for AGC timing
Gain		Selects fixed gain. Default 40 dB.
VDD (mic)		mic?

const int micPin = A0;  // Analog pin for MAX9814 output

void setup() {
  Serial.begin(9600);
}

void loop() {
  int micValue = analogRead(micPin);
  Serial.println(micValue);
  delay(50);
}

Frequency Detection

• 

  400 Hz sine wave works perfectly.

• 

  800 Hz sine wave works even better.

• Error creating thumbnail: File with dimensions greater than 12.5 MP

  The code from the Arduino forum, post 42!

https://www.instructables.com/Arduino-Frequency-Detection/

• Direct port manipulation because it is faster than writing.
• Interrupt routine at 38.5 kHZ: https://www.instructables.com/Arduino-Timer-Interrupts/

https://forum.arduino.cc/t/arduino-pitch-detection-in-realtime-using-autocorrelation-and-peak-detection/519783/42

• Post #42 of that thread.
• 9615.4 samples per second.
• Works!

Guitar tuner

The guitar's strings should have the following frequencies:

• E: 82.4 Hz
• A: 110 Hz
• D: 146.8 Hz
• G: 196 Hz
• B: 246.9 Hz
• E: 329.6 Hz

INMP441

Digital I2S MEMS microphone.

SPH0645

Digital I2S MEMS microphone.

Hiwonder sound module

A microphone and LM358 amplifier.

LM358 Operational Amplifier Module

To amplify the analog data.