Producing sounds with PWM and a piezo buzzer

Blog post for more:
http://jallib.blogspot.com/2009/02/step-by-step-having-fun-with-pwm-and_14.html

Category:

Science & Technology

Tags:

• jal
• jalv2
• jallib
• 16f88
• PIC
• microcontroller
• piezo
• piezzo
• buzzer
• PWM
• frequency
• duty
• cycle
• sounds

[TheToploaderwasher]

The speaker looks like something out of an alarm clock... ;-)

[strangerlover11]

I have a carless home telephon but it original buzzer burned I replace the new one with 3 volts but it needs 12watts and the sound is so slow so what I

hve to do to increase the sound thanks pleas.

[yetihehe]

It's not PWM (Pulse Width Modulation) but PFM (Pulse Frequency Modulation). Pulse width is constant 50% (not modulated).

[GTechno13]

@fennecfanatic ehhh sort of not really. I think buzzers usually do best at 50% duty cycle and then probably taper off above and below that but PWM is not a good way to change volume. I tried it once a long time ago and remember noting not to do it again. Made it sound weird and screwed up.

[fennecfanatic]

@GTechno13 so PWM into a buzzer would produce the same frequency at different amplitudes?

[GTechno13]

Exactly the opposite. Pulse width modulation means your are modifying the duty cycle at a fixed frequency. I just want to clear that up for viewers. PWMing a buzzer will not produce different frequencies.

[schudder]

@GTechno13 sure it is. It's pwm with a 50% duty cycle and a varying frequency.

[GTechno13]

This is NOT PWM.