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I consider this post a birthday present and didn't even try to resist the buy-instantly-reflex..

BUT. What I'm still missing is an audio jack. I've been searching for a long time now for a device of this mobile friendly form factor (i.e. battery support), with a couple of buttons and knobs, a small display and audio in/out.

Like a TE Pocket Operator, but fully programmable (using typical C++/Rust/Micropython programming environments).

I'd really love to deep dive into rapid prototyping some audio generator or effect processor I can take with me, but don't want to design and build a device for this first.

Maybe you guys have seen something like this before and can give me a hint?

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The esp32 has i2s[1] and there are a variety of i2s DAC chips for very reasonable prices. Amazon has what looks like a reasonable low-cost choice, the PCM5102 breakout board for $12 [2]

1. https://docs.espressif.com/projects/esp-idf/en/latest/esp32/... 2. https://www.amazon.com/HiLetgo-Lossless-Digital-Converter-Ra...

Or $3 (on sale) from AliExpress [1].

[1]: https://www.aliexpress.com/item/1005006104038963.html?spm=a2...

The ESP32 also has two onboard 8-bit DACs. But I agree, a 16-bit I2S DAC is a better choice for high quality audio. I built a streaming audio receiver for a custom car stereo with them and it sounds amazing.

https://wiphone.io/ is Arduino compatible and comes with an audio jack and microphone. It's also completely enclosed, knows how to charge it's own battery, etc. Phone form factor, ESP32 processor.

The back of the phone can be replaced with a custom PCB or breadboard holding your custom hardware. Pogo pins make a connection to the motherboard. The idea is you could carry whatever you end up making around in your pocket just like a phone once you're done, assuming you only put components on the inside of the back cover.

Disclosure: I designed and manufacture it.

There are numerous $50-100 Rockchip-based GameBoy-like emulation handhelds on the market, such as the R36S. The R36S runs normal Linux (ArkOS/Ubuntu), has an audio jack along with numerous buttons. It's missing a touchscreen and WiFi, but has an USB port to plug in a keyboard or WiFi adapter (USB port is somewhat current limited, so it won't work with all).

Yeah it should have audio.

Next best is using Bluetooth, depending on what you’re trying to build.

Just add one yourself? I mean it even has a speaker cable. That said an esp32 isn't that good for audio just from a practical standpoint.

> That said an esp32 isn't that good for audio just from a practical standpoint.

What are the problems with it for audio? The microphones and speaker on this and the T-Embed [1] suggest it's partly intended for that.

[1] https://www.lilygo.cc/products/t-embed

My recollection is that by default the ESP32 DAC isn't very high bit depth and so the sound quality is limited. It is recommended to interface it with an external DAC chip via I2S in order to achieve higher than 8bits per sample (maybe 12bit? Someone please correct me).

yes it hasn't really got a dedicated sound out and an i2c chips is absolutely needed. I meant more because while is absolutely possible to play say an mp3 on it its simple not a thing it does too easily in a useful manner in a multi-application device context.

I mean you can absolutely build a shoutcast stream receiver with it. Or run a NES emulator with sound on it. But this ttgo device seem like it would be best as a console or maybe a mastodon front-end. In that case the most the speaker would make sense for would be some beeps.

Correct. Configuring it to route audio through an external I2S DAC instead is trivial. ISTR that it's literally 3 lines of code.

I wonder how many people buy such products once it's displayed on the frontpage of HN.

I would wager both more and less than you think.

The total amount of readers is probably higher than you think, 80% are lurkers.

The total amount of purchasers ass a percentage is probably lower than average, due to cynacism and skeptacism.

Take a look at the Woovebox. A great example of what a lone dev can do with esp32

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