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Okay, kinda a noob here. I've been looking around, trying to find an answer to playing audio via the PWM pins. I tried rerouting the audio to no avail. I've tried making a script that uses PWM to play audio over the pins. I just can't get it to work at all.

Pi GPIO connections: Speaker+ on GPIO 18 (PWM 0); Speaker- on GND

Visual representation (- = speaker negative, + = speaker positive):

..-..+.............. ....................

I am not sure what I am doing wrong. Any help is appreciated.

P.S. Yes, the speaker and all the pins on my Pi work.

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1 Answer 1

Reset to default
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Default audio uses PWM (AFAIK pins 40,41).

It is POSSIBLE to enable PWM on header pins (which will disable headphone jack), and there are a few tutorials explaining this - mainly intended for those models without headphone jack, but will work on any Pi. Frankly there seems little point.

Enable with dtoverlay audremap:-

Name: audremap Info: Switches PWM sound output to GPIOs on the 40-pin header Usage: dtoverlay=audremap,<param>=<val> Params: swap_lr Reverse the channel allocation, which will also swap the audio jack outputs (default off) enable_jack Don't switch off the audio jack output. Does nothing on BCM2711 (default off) pins_12_13 Select GPIOs 12 & 13 (default) pins_18_19 Select GPIOs 18 & 19 pins_40_41 Select GPIOs 40 & 41 pins_40_45 Select GPIOs 40 & 45 (don't use on BCM2711 - the pins are on different controllers)

BUT you will have to supply the filtering circuitry (explained in tutorials)

NOTE this will generate line level output; it won't drive a speaker.

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  • You sure? I added dtoverlay=audremap,pins_18_19 and it started driving the speaker just fine. Commented Jan 22, 2023 at 14:47
  • It depends on the (unspecified) "speaker". A typical loudspeaker is low impedance and will produce almost inaudible sounds and will place a DC load which will overload the GPIO. It may work for a high impedance headphone. Commented Jan 22, 2023 at 21:04
  • It appears to work really well on my iMac G3 speakers. It's just a little quiet even on max volume. But other than that it's 100% usable. Commented Jan 22, 2023 at 21:38

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