That was measured with a scope with 4kHz signal. There's no negative voltage if I drop the GPIO drive strength to minimum. I would not expect a piezo transducer to work well if it's just in series with the drain of a transistor but that should be OK for the electro-magnetic transducer. Cool, at lea...

Just an FYI, it's not a good idea to drive a piezo electric device via a GPIO pin. Piezo devices can generate negative voltages. I'm getting only -40mV. Is that measured with a scope or meter. You will get much higher voltages than this when you turn a piezo off at the right time. Similar to say wh...

It would help if you provide a link to the type of buzzer you are using. It sounds to me as if it's probably a piezo transducer such as this. If so, drive it directly from a GPIO, not through a transistor. Just an FYI, it's not a good idea to drive a piezo electric device via a GPIO pin. Piezo devi...

ok, cool. what about "Did you look at the pin via a scope to ensure your getting the square wave output ?"

FWIW, prototypes have been send out. Will receive them next week.

Need a little more info.
How are you driving the buzzer? GPIO directly, though a transistor, and if transistor did you add the blocking diode.
Did you look at the pin via a scope to ensure your getting the square wave output ?

Thanks for sharing, nice job!

I just tried this example using mingw32, compiled and ran just fine for me.

The PSRAM is not the best option, since it uses up the precious SPI bus for flash reads.

Maybe, dedicated pads for PSRAM.

Never hurts to ask. What are you powering the ESP32 with, and what are you measuring the current with.