SunFounder Thales Kit, Manual

Page: 88 / 167

SunFounder Thales Kit for Raspberry Pi Pico, Release 1.0
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tone(buzzer, 494 , 250 )
utime . sleep_ms( 500 )
tone(buzzer, 523 , 250 )
How it works?
If the passive buzzer given a digital signal, it can only keep pushing the diaphragm without producing sound.
Therefore, we use the
tone()
function to generate the PWM signal to make the passive buzzer sound.
This function has three parameters:
•
pin
, the GPIO pin that controls the buzzer.
• frequency , the pitch of the buzzer is determined by the frequency, the higher the frequency, the higher the pitch.
• Duration , the duration of the tone.
We use the
duty_u16()
function to set the duty cycle to 30000(about 50%). It can be other numbers, and it only
needs to generate a discontinuous electrical signal to oscillate.
What more
We can simulate the specific tone according to the fundamental frequency of the piano, so as to play a complete piece
of music.
• Piano key frequencies - Wikipedia
import machine
import utime
NOTE_C4 = 262
NOTE_G3 = 196
NOTE_A3 = 220
NOTE_B3 = 247
melody = [NOTE_C4,NOTE_G3,NOTE_G3,NOTE_A3,NOTE_G3,NOTE_B3,NOTE_C4]
buzzer = machine . PWM(machine . Pin( 15 ))
def tone (pin,frequency,duration):
pin . freq(frequency)
pin . duty_u16( 30000 )
utime . sleep_ms(duration)
pin . duty_u16( 0 )
for note in melody:
tone(buzzer,note, 250 )
utime . sleep_ms( 150 )
84 Chapter 3. For MicroPython User