Lesson 12 Buzzer

Introduction

Buzzers can be categorized as active buzzers and passive ones (See the following picture).

 

Components

- 1 * SunFounder Uno board

- 1 * USB data cable

- 1 * Buzzer module

- Several jumper wires

 

Experimental Principle

Place the pins of two buzzers face up and you can see the one with a green circuit board is a passive buzzer, while the other with a black tape, instead of a board, is an active buzzer, as shown below.

 

An active buzzer has a built-in oscillating source, so it will make sounds when electrified. But a passive buzzer does not have such source, so it will not beep if DC signals are used; instead, you need to use square waves whose frequency is between 2K and 5K to drive it. The active buzzer is often more expensive than the passive one because of multiple built-in oscillating circuits.

 

Experimental Procedures

Passive Buzzer

Step 1: Build the circuit

                      Passive Buzzer Module              SunFounder Uno

                                 S ------------------------------------- D11

                                 - ------------------------------------ GND

                                 + -------------------------------------- 5V

Step 2: Program (Please refer to the example code in LEARN -> Get Tutorial on our website)

Step 3: Compile

Step 4: Upload the sketch to SunFounder Uno

 

Now, you can hear the passive buzzer beep for warning.

 

 

Active Buzzer

 

Note: The active buzzer has built-in oscillating source, so it will beep as long as it is electrified, but it can only beep with a fixed frequency.

 

Step 1: Build the circuit

 

                             Active Buzzer Module             SunFounder Uno

 

                                          S ------------------------------------ D1

 

                                          - ----------------------------------- GND

 

                                          + ------------------------------------ 5V

 

Step 2: Program (Please refer to the example code in LEARN -> Get Tutorial on our website)

 

Step 3: Compile

 

Step 4: Upload the sketch to SunFounder Uno

 

 

Now, you can hear the active buzzer beep.

 

Code for Passive

/*******************************************/
const int buzzerPin = 3;//the buzzer pin attach to
int fre;//set the variable to store the frequence value
/*******************************************/
void setup()
{
pinMode(buzzerPin,OUTPUT);
}
/*******************************************/
void loop()
{
for(int i = 200;i <= 800;i++) //frequence loop from 200 to 800
{
tone(3,i); //turn the buzzer on
delay(5); //wait for 5 milliseconds
}
delay(4000); //wait for 4 seconds on highest frequence
for(int i = 800;i >= 200;i--)//frequence loop from 800 downto 200
{
tone(3,i);
delay(10);
}
}

 

Code for Active

int buzzer = 11;//the pin of the active buzzer
void setup()
{
pinMode(buzzer,OUTPUT);//initialize the buzzer pin as an output
}
void loop()
{
unsigned char i,j;
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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