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by mikemoy
Fri Jun 01, 2018 11:59 pm
Forum: General Discussion
Topic: use of LED control for buzzer?
Replies: 12
Views: 6731

Re: use of LED control for buzzer?

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...
by mikemoy
Fri Jun 01, 2018 10:04 pm
Forum: General Discussion
Topic: use of LED control for buzzer?
Replies: 12
Views: 6731

Re: use of LED control for buzzer?

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...
by mikemoy
Fri Jun 01, 2018 9:22 pm
Forum: General Discussion
Topic: use of LED control for buzzer?
Replies: 12
Views: 6731

Re: use of LED control for buzzer?

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...
by mikemoy
Fri Jun 01, 2018 5:47 pm
Forum: General Discussion
Topic: use of LED control for buzzer?
Replies: 12
Views: 6731

Re: use of LED control for buzzer?

ok, cool. what about "Did you look at the pin via a scope to ensure your getting the square wave output ?"
by mikemoy
Fri Jun 01, 2018 5:10 pm
Forum: Showcase
Topic: New ESP32-WROVER Ethernet Board
Replies: 34
Views: 45959

Re: New ESP32-WROVER Ethernet Board

FWIW, prototypes have been send out. Will receive them next week.
by mikemoy
Fri Jun 01, 2018 5:07 pm
Forum: General Discussion
Topic: use of LED control for buzzer?
Replies: 12
Views: 6731

Re: use of LED control for buzzer?

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 ?
by mikemoy
Tue May 29, 2018 5:28 pm
Forum: Hardware
Topic: A New Pinout Diagram for DOIT ESP32 Devkit Board
Replies: 2
Views: 3792

Re: A New Pinout Diagram for DOIT ESP32 Devkit Board

Thanks for sharing, nice job!
by mikemoy
Tue May 29, 2018 4:56 pm
Forum: General Discussion
Topic: Error when flashing gpio example
Replies: 3
Views: 2190

Re: Error when flashing gpio example

I just tried this example using mingw32, compiled and ran just fine for me.
by mikemoy
Mon May 28, 2018 4:07 pm
Forum: General Discussion
Topic: What would you like to see in The Next Chip?
Replies: 398
Views: 221579

Re: What would you like to see in The Next Chip?

The PSRAM is not the best option, since it uses up the precious SPI bus for flash reads.
Maybe, dedicated pads for PSRAM.
by mikemoy
Sat May 26, 2018 7:11 pm
Forum: General Discussion
Topic: Wrong ULP Consumption ?
Replies: 9
Views: 5105

Re: Wrong ULP Consumption ?

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

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