Chapter 6 Buzzer

In this chapter, we will learn about buzzers that can make sounds.

Project 6.1 Doorbell

We will make this kind of doorbell: when the button is pressed, the buzzer sounds; and when the button is released, the buzzer stops sounding.

Component List

  • ESP32-S3-WROOM x1

  • GPIO Extension Board x1

  • 830 Tie-Points Breadboard x1

  • NPN transistor(S8050) x2

  • Active Buzzer x1

  • Resistor 10kΩ x2

  • Resistor 1kΩ x1

  • Button x1

  • Jumper Wire x6

Component knowledge

transistor

Buzzer

Connect

../_images/61.png

Code

In this project, a buzzer will be controlled by a push button switch. When the button switch is pressed, the buzzer sounds and when the button is released, the buzzer stops. It is analogous to our earlier project that controlled an LED ON and OFF.

Move the program folder Super_Starter_Kit_for_ESP32_S3/Python/Python_Codes to disk(D) in advance with the path of “D:/Micropython_Codes”.

Open “Thonny”, click This computer/D:/Micropython_Codes/06.1_Doorbell and double click “Doorbell.py”.

06.1_Doorbell

../_images/6.12.png

Click “Run current script”, press the push button switch and the buzzer will sound. Release the push button switch and the buzzer will stop.

../_images/6.13.png

The following is the program code:

from machine import Pin

button=Pin(21,Pin.IN,Pin.PULL_UP)
activeBuzzer=Pin(14,Pin.OUT)

activeBuzzer.value(0)

while True:
    if not button.value():
        activeBuzzer.value(1)
    else:
        activeBuzzer.value(0)

Project 6.2 Alertor

Next, we will use a passive buzzer to make an alarm. Component list and the circuit is similar to the last section. In the Doorbell circuit only the active buzzer needs to be replaced with a passive buzzer.

Code

In this project, the buzzer alarm is controlled by the button. Press the button, then buzzer sounds. If you release the button, the buzzer will stop sounding.

In the logic, it is the same as using button to control LED. In the control method, passive buzzer requires PWM of certain frequency to sound.

Open “Thonny”, click This computer/D:/Micropython_Codes/06.2_Alertor，and double click “Alertor.py”.

06.2_Alertor

../_images/6.21.png

Click “Run current script”, press the button, then alarm sounds. And when the button is release, the alarm will stop sounding.

../_images/6.13.png

The following is the program code:

from machine import Pin,PWM
import math
import time

PI=3.14
button=Pin(21,Pin.IN,Pin.PULL_UP)
passiveBuzzer=PWM(Pin(14),2000)

def alert():
    for x in range(0,36):
        sinVal=math.sin(x*10*PI/180)
        toneVal=2000+int(sinVal*500)
        passiveBuzzer.freq(toneVal)
        time.sleep_ms(10)
try:
    while True:
        if not button.value():
            passiveBuzzer.init()
            alert()
        else:
            passiveBuzzer.deinit()
except:
    passiveBuzzer.deinit()