Active Buzzer

The difference between the two is that an active buzzer has a built-in oscillating source, so it will generate a sound when powered. A passive buzzer does not have such so it makes no sound if powered; instead, you need to use square waves whose frequency is between 2K and 5K to drive it. The Arduino makes the process very easy using libraries. Let's look at how to use the active buzzer to get sound feedback from the Arduino.

Active Buzzer Schematic

Active Buzzer Sketch

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int buzzer = 12;    //connect active buzzer to pin 12

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void setup(){
pinMode(buzzer, OUTPUT);  //initialize the buzzer pin as an output
}

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void loop(){
unsigned char i;
while(1)
{
   //output an frequency
   for(i=0;i<80;i++)
   {
    digitalWrite(buzzer, HIGH);
    delay(1);//wait for 1ms
    digitalWrite(buzzer, LOW);
    delay(1);//wait for 1ms
    }
    //output another frequency
     for(i=0;i<100;i++)
      {
        digitalWrite(buzzer,HIGH);
        delay(2);//wait for 2ms
        digitalWrite(buzzer,LOW);
        delay(2);//wait for 2ms
      }
  }
} 

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First we indicate the pin our active buzzer is connected to which in our case is pin 12. Next, inside our setup function, we use the pinMode() function to initialize that the connected pin would act as output to our buzzer. Next, in our loop function we make use of the while loop. Before then, we declare an unsigned datatype char which encodes numbers from 0 to 255. Going back to our while loop, it will loop continuously, until the expression inside the parenthesis, () becomes false. Inside the while loop we use a for loop to set our frequency. Upload your sketch above to your Arduino and listen to your Arduino beep at intervals.