Sound level meter

Overview

As you rotate the volume, the number of LEDs light up in proportion to the amount of rotation. You can also turn on the number of LEDs according to the ambient volume with the microphone.

Leaf to use

Use the following leaves.

Type	Name	Q’ty
AI03	MIC&VR&LED	1
AP01	AVR MCU	1
AV01	CR2032	1
AZ01	USB	1
AZ62	Connector Cover	1
	CR2032 coin cell battery	1
	M2*15mm screw	2

Assembly

Let’s assemble leaves as shown in the figure below.

Source code

Write the following program in the Arduino IDE.

//=====================================================================
//  Sound level meter
//
//    (c) 2020 Trillion-Node Study Group
//    Released under the MIT license
//    https://opensource.org/licenses/MIT
//
//      Rev.00 2020/05/17  First release
//=====================================================================
#define LED1             6
#define LED2             7
#define LED3             8
#define LED4             9
#define LED5            10
#define LED6            11

#define MIC             16      // A2
#define VR              17      // A3

unsigned int dataVR;
unsigned int dataMic;

//-----------------------------------------------
// Get VR and MIC data
//-----------------------------------------------
void getSensorData()
{
    dataVR = analogRead(VR);
    dataMic = analogRead(MIC);

    Serial.println("---------------------");
    Serial.print("MIC  = ");
    Serial.println(dataMic,DEC);
    Serial.print("VR   = ");
    Serial.println(dataVR,DEC);
}

//-----------------------------------------------
// Turn the LEDs on and off according to the VR and MIC values.
//-----------------------------------------------
void dispSensorData()
{
    if (dataVR < 400)
    {
      digitalWrite(LED4,LOW);
      digitalWrite(LED5,LOW);
      digitalWrite(LED6,LOW);
    }
    else if (dataVR >= 400 && dataVR < 800)
    {
       digitalWrite(LED4,LOW);
       digitalWrite(LED5,LOW);
       digitalWrite(LED6,HIGH);
    }
    else if (dataVR >= 800 && dataVR < 900)
    {
       digitalWrite(LED4,LOW);
       digitalWrite(LED5,HIGH);
       digitalWrite(LED6,HIGH);
    }
    else
    {
       digitalWrite(LED4,HIGH);
       digitalWrite(LED5,HIGH);
       digitalWrite(LED6,HIGH);
    }

    if (dataMic < 700)
    {
      digitalWrite(LED1,LOW);
      digitalWrite(LED2,LOW);
      digitalWrite(LED3,LOW);
    }
    else if (dataMic >= 700 && dataMic < 800)
    {
      digitalWrite(LED1,LOW);
      digitalWrite(LED2,LOW);
      digitalWrite(LED3,HIGH);
    }
    else if (dataMic >= 800 && dataMic < 850)
    {
      digitalWrite(LED1,LOW);
      digitalWrite(LED2,HIGH);
      digitalWrite(LED3,HIGH);
    }
    else
    {
      digitalWrite(LED1,HIGH);
      digitalWrite(LED2,HIGH);
      digitalWrite(LED3,HIGH);
    }
}


void setup() {
  Serial.begin(115200);
  Serial.println("start!!");

   pinMode(LED1, OUTPUT);
  digitalWrite(LED1, LOW);
  pinMode(LED2, OUTPUT);
  digitalWrite(LED2, LOW);
  pinMode(LED3, OUTPUT);
  digitalWrite(LED3, LOW);
  pinMode(LED4, OUTPUT);
  digitalWrite(LED4, LOW);
  pinMode(LED5, OUTPUT);
  digitalWrite(LED5, LOW);
  pinMode(LED6, OUTPUT);
  digitalWrite(LED6, LOW);

  pinMode(MIC, INPUT);
  pinMode(VR, INPUT);

  //起動テスト(LED)
  digitalWrite(LED1,HIGH);
  delay(200);
  digitalWrite(LED2,HIGH);
  delay(200);
  digitalWrite(LED3,HIGH);
  delay(200);
  digitalWrite(LED4,HIGH);
  delay(200);
  digitalWrite(LED5,HIGH);
  delay(200);
  digitalWrite(LED6,HIGH);
  delay(200);
  digitalWrite(LED1,LOW);
  digitalWrite(LED2,LOW);
  digitalWrite(LED3,LOW);
  digitalWrite(LED4,LOW);
  digitalWrite(LED5,LOW);
  digitalWrite(LED6,LOW);
  delay(200);
}


void loop() {
  getSensorData();
  dispSensorData();
  delay(100);
}

Sound_Level_Meter.ino

Execution Results

As you rotate the volume, the number of LEDs will light up according to the amount of rotation. The number of LEDs will light up according to the ambient volume, depending on the microphone.