Buzzer Sound with Low-Power PWM Library

RE: Buzzer Sound with Low-Power PWM Library

ovrebekk — Wed, 24 Apr 2019 12:46:04 GMT

Hi Joseph

As mentioned by Andrew the PWM driver is a much better option than the low power PWM library. It is documented here.

I would also strongly suggest looking at the nRF52 series instead of the nRF51 series, as the nRF52 devices have dedicated PWM modules with DMA support, making it much easier to playback a wave file from RAM (assuming you are fine with 8-bit sound).

Best regards
Torbjørn

RE: Buzzer Sound with Low-Power PWM Library

Joseph Ayuk — Sat, 20 Apr 2019 09:35:19 GMT

Yeah Exactly, It is a speaker I want to use to play a .wav file

RE: Buzzer Sound with Low-Power PWM Library

awneil — Sat, 20 Apr 2019 08:50:38 GMT

I don't know - you'll have to investigate ...

What do you mean by, "suitable".

What kind of "buzzer" (sic?) are you using?

Clearly, it's not going to give you CD quality!!

I'd also missed that you're using nRF51. The nRF52 are more powerful, so would have a better chance; they also have I2S ...

RE: Buzzer Sound with Low-Power PWM Library

Joseph Ayuk — Sat, 20 Apr 2019 08:46:24 GMT

Thanks for your reply awneil but can the PWM Driver or PWM Library play a suitable melody like maybe the Pirate of Carribean theme on my buzzer ? I really doubt that.

RE: Buzzer Sound with Low-Power PWM Library

awneil — Sat, 20 Apr 2019 08:44:25 GMT

Note that "buzzer" is usually taken to mean a device which internally generates its own tone - so you just apply power to it, and goes Buzzzzzzzzzz or Beeeeeeeeeeeep or whatever.

You don't want one of those!

What you need is usually called "speaker" (or, sometimes, a "sounder")

RE: Buzzer Sound with Low-Power PWM Library

awneil — Sat, 20 Apr 2019 08:41:04 GMT

IIRC, the "Low-power PWM Library" does all its cycle-to-cycle updates in software - so is not suitable for constantly varying duty cycles like this.

I suggest looking at the 'PWM Driver' or 'PWM Library' examples instead

"The PWM Library Example demonstrates the use of the pulse-width modulation library by generating waveforms over a GPIO. The GPIO pin could drive a small speaker, for example"

https://infocenter.nordicsemi.com/topic/com.nordic.infocenter.sdk5.v15.3.0/pwm_example.html

RE: Buzzer Sound with Low-Power PWM Library

Joseph Ayuk — Sat, 20 Apr 2019 08:26:09 GMT

I want to play a suitable melody on a speaker connected to my nrf51 dk. I am doubting if the PWM library will satisfy my needs. Is it possible to use a .wav file to play a melody on my speaker connected to the board ? Besides usng Low-power pwm library.

RE: Buzzer Sound with Low-Power PWM Library

awneil — Sat, 20 Apr 2019 08:04:50 GMT

What do you mean, "play a buzzer" ?

If you just want a tone, you don't need PWM at all - just a timer.