Ive been thinking of cooking up a set of boards based upon your design, expanding some of the functionality.. and this is what Ive planned to change so far, but if you want to implement any of these it then go for it..
SuperCAP instead of Battery for RTC so it never needs replacing.
A more powerful 5v supply (2A perhaps) and a set of headers available for 5v out, can then solder jumper wire with a barrel plug onto it and have it power a small usb hub.. this will help people with powerful wifi usb chips and/or those who want to connect several usb devices without any reliability/stability issues.
Header for a TPM36 Temperature Sensor on the board; mebe included so we can monitor system temperature if installed in a Greenhouse etc.
A PTC Fuse instead.
Signal Converter so we can plug some analogue sensors in and not worry about the input voltage.
Circuitry to cutoff the external 5v rail to the Microcontroller if its powered externally/usb so people can troubleshot bad power supplies.
AC in with Ground, Microcontroller ground tied in so any ESD coming in the sprinkler control lines does not try to go out ethernet/usb, also help cut down on RF interference.. my Elk power supply has a ground it’d be nice to use.
I also want to add a few serial ports for AtlasScientic Sensor stamps: https://www.atlas-scientific.com/embedded.html but this is more for my own project where I am attempting to maintain PH and TDS automatically and getting it all into the footprint might mean I sacrifice some other circuitry.. but this could also be done with a via USB conveniently if I can power a hub from the board. (Bluetooth or FT232)
Thanks ray for the project; I wish I had found it before I had a year of circuit designs and prototypes made up :geek: