The project I am planning is a camera which takes four images simultaneous (4x ESP32 with cam) and sends them to a Raspberry Pi for further processing. For sending the images I want to use MQTT messages, as it's easy to use an I need it for other projects anyway.
My question is mainly regarding connecting the four ESP32s to the Raspberry Pi. I could just use the Raspberry Pi as WiFi hotspot and the ESP32s as clients, but this takes time to dial in and is never as stable as a wired connection.
Things I thought about already, but I am not sure about:
- Add a Ethernet shield to all the ESP32s (maybe with PoE) and use a little 5 port switch to connect them
- Somehow use four times the USB directly to the Raspberry Pi with USBNET. I found it's possible on the Raspberry side, but could not find anything about the ESP32.
What are other not to pricy, easy and reliable ways to connect them to get a network connection?
I also consider to use 4x Raspberry Pi Zeros over USBNET (or RJ45 Ethernet) if this makes more sense.
Finally everything should be running off a battery. Hence energy consumption is also an issue...
Thanks for your input!