I window shop for these on AliExpress. Most ads are unclear about
just what modules they use.
This is why using established designers and resellers is a good idea. Even on AliExpress, there are vendors who develop their own hardware and support it well, often with github repos of code and actually-usable documentation. These may not be the cheapest vendors. For me, these include:
- LOLIN — https://lolin.aliexpress.com/store/1331105 . LOLIN - aka Wemos - developed the little D1 Mini format board years ago, and have developed many variants and support boards. Their documentation site https://www.wemos.cc/en/latest/index.html is as close to great as you'll get in this market. Their boards typically come flashed with the latest version of MicroPython, very lightly tweaked so it's easy to use the right pins.
- lilygo — https://lilygo.aliexpress.com/store/2090076 . They have many more imaginative products such as ESP32-based smart watches and ham radio transceivers. Not cheap, but interesting.
- WeAct Studio — https://weactstudio.aliexpress.com/store/910567080 . Very barebones boards, but their production QC/finish is remarkably good and they've actually bothered to put some unnecessarily nice features into their products. Their low-end ESP32-C3FH4 board is about the cheapest ESP32 board that you know what you're getting.
The "camera" variant seems like a lot of bang for the buck.
As someone who is professionally interested in imaging now, these things are amazing. The very cheapest ones can make a simple 3d printer monitor, if you don't mind a terrible frame rate for your $3. Some of the higher-end ones are beginning to come out with 5-6 mpix autofocus modules. For imaging, you really need as much RAM (preferably built-in, not PSRAM through the SPI bus) as possible. I don't think that even the ESP-S3 has enough processing power to do "AI stuff" like object recognition on board, but the more expensive STM32H7 camera boards (WeAct do one) can. You're not going to run a YOLO large model on it, but it will do a bunch of processing on-board
Stewart