Connect the output to a Digital Storage Oscilloscope to see the variations in output with the sound signals on electret MIC.

Upload the following program to Arduino board

//Pin connected to ST_CP (12) of 74HC595
int latchPin = 12;
//Pin connected to SH_CP (11) of 74HC595
int clockPin = 11;
////Pin connected to DS (14) of 74HC595
int dataPin = 10;

int numDigitArray[7] = {0, 0, 0, 0, 0, 0, 0};
int dotPointArray[7] = {0, 0, 0, 0, 0, 0, 0};

void displayValueAndDigit(byte value,

#define D0 9 // A terminal of seven segment display module
#define D1 10 // B terminal of seven segment display module
#define D2 11 // C terminal of seven segment display module
#define D3 12 // D terminal of seven segment display module

#define LE1 2
#define LE2 3
#define LE3 4
#define LE4 5
#define LE5 6
#define LE6 7
#define LE7 8

// the setup function runs once when you press reset or power the board
void setup() {
// initialize digital pins as output.