Still an early draft, but show the 8 RS-485 connectors at top/bottom. I only use right angle headers in the 3D, but they are 2.54 pich so they can be replaced with other connectors.
I still have a few loose ends. RS485 circuit can be switched off into 3-state by setting RE High and DE Low (Neither receiving or sending). I need a similar way for the ESP32 to switch off the STM32F405RG so we can go low power. I also want a 3.7V Battery connected on the back.
I should have plenty with spare pins so we can add a few more leds etc. I do however need to solder up a RS485 (or find a breakout) and test that I can get UARTS where I want on ESP32.