I’m trying and (Google is) failing to find some good examples that use analogWrite() – true analog, not PWM. Does anyone have any ideas?

Reference and examples here: https://docs.particle.io/reference/firmware/electron/#analog-output-dac- // SYNTAX pinMode(DAC1, OUTPUT); analogWrite(DAC1, 1024); // sets DAC pin to an output voltage of 1024/4095 * 3.3V = 0.825V.

I've posted some PoC for playing some raw audio via analogWrite() [image] Photon play sampled music (wav file) using DAC General It shouldn’t be too complicated when using SparkIntervalTimer library to push the samples in a “sort of steady” pace to the two DACs. Try this …

I’d seen that, but I was actually wondering about practical applications. So far I’ve seen music and sound, which are admittedly pretty good…

Thanks, ScruffR. I got it to play an 880 Hz sound, although I did need to reset the Photon before it would talk to the cloud again, I think because the system mode was manual. I was trying to see what this – https://go.particle.io/shared_apps/5aef6f695286fce9cb00035e (from your post on Audio, SD ca…

Not quite sure what you mean by practical, but take a look at my APRS library. I use analogWrite to generate a Bell 202 modem (1200 baud) tone using AFSK to encode data for radio transmission. Typical use is for building a High Altitude Balloon tracker, or tracking anything.

[image] mprogers: I was trying to see what this Sorry for that, I have since removed the app but totally forgot about the link to it. I'll try to see if I can find it somewhere. @mprogers , I've found my project. I filed it as Pull Request with @jvanier 's particle-speaker library …

Update: @jvanier has just merged my PR and now you can use the sample directly from the library 1.1.0 You will need to provide your sounds in a sound.h header tho’, since USE THIS EXAMPLE does not copy over the provided sound.h. Alternatively you can select sound.h and hit USE THIS EXAMPLE and ju…

Thank you! I can see many places where this would be useful (especially once I get the amplifier they’d mentioned: right now I can barely hear it). I don’t see where it’s actually calling analogWrite(), though – what’s the mechanism that’s making it walk through the buffer? As usual, I know there’s …

The speaker library is not using analogWrite() but the underlying (low level) function that’s also used by analogWrite() but in a more sophisitcated way. In order to provide constant timing, the controller is setup to directly feed the contents of the sound buffer to the pin each time a hardware ti…

Thanks for the explanation, this gives me a good starting point. As far as the speaker is concerned, it’s just a little piezo-speaker, the only one that I had close at hand.

analogWrite (DAC) Examples?

General

ScruffR July 10, 2018, 9:40am 3

I've posted some PoC for playing some raw audio via analogWrite()

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analogWrite (DAC) Examples?

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