To do this, we create a project called buzzer. You can see that the project structure in figure 3-11. The buzzer.c file is our main program:

Firstly, we declare all required header files and define IO27 for the sound buzzer:

#include <stdio.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "driver/gpio.h"
#include "sdkconfig.h"

#define BUZZER 27

We also define the main entry on the app_main() function. This function will execute the buzzer_task() function:

void app_main()
{
    xTaskCreate(&buzzer_task, "buzzer_task", configMINIMAL_STACK_SIZE, NULL, 5, NULL);
}

Technically, we generate sound on the sensor by giving HIGH on IO27. We can use the gpio_set_level() function for this. The following is an implementation of the buzzer_task() function:

void buzzer_task(void *pvParameter)
{
    // set gpio and its direction
    gpio_pad_select_gpio(BUZZER); 
    gpio_set_direction(BUZZER, GPIO_MODE_OUTPUT); 

    int sounding = 1;
    while(1) {

        if(sounding==1){
            gpio_set_level(BUZZER, 1);
            sounding = 0;
        } 
        else {
            gpio_set_level(BUZZER, 0);
            sounding = 1;
        }
            
        vTaskDelay(1000 / portTICK_PERIOD_MS);
                
    }
}

Once you have saved this program, you can compile and flash the program onto the ESP32 board.

When this has successfully completed, you should hear a sound from the buzzer device.