Buzzer interface with 8051 microcontroller

Buzzer is a electronic device that converts the electronic signal into buzzing noise, that is applied to it. It can be used as electronic bell or as quiz buzzer in many applications around us. Here, i world like to discuss the interfacing of a small buzzer with 8051 microcontroller and how different projects can be constructed.

Buzzer Interfacing:

This project shows the interface with AT89S52 microcontroller to a buzzer. When a push button is pressed, the buzzer will get ON and OFF (number of times set in the code) and then stops.

Circuit Diagram:

- The port P1 of the microcontroller is connected to buzzer. This type of connection is possible, if the current requirements of the buzzer is not more than 20mA. The output is in current source mode so that buzzer will turn ON when the output of the port is logic LOW. Switch is connected to port P3 which remains at logic HIGH by pull up resistor.

 Code:

#include "REG52.h"
#define buz P1

sbit SW=P3^0;
long int i;
void main()
{
while(1)
{
if (SW==0)
{ 
for(i=0;i<=90000;i++);
if(SW==0)
{

while(SW==0);
buz=0x01;      // ON Buzzer
for(i=0;i<4500;i++);     // Delay
buz=0x00;       // OFF Buzzer

for(i=0;i<4500;i++);  // Delay
}  }
}  }

According to the code: The buzzer is interfaced to Port P1 of the microcontroller and simple ON/OFF program is written as an example using delay in between them. For half period, buzzer gets ON automatically and for next half period, buzzer gets OFF automatically as described in the code. One can also use the switch concept to control the ON/OFF operation of buzzer. Here, switch is connected to Port P3.0 pin and Debouncing concept is applied.