Hi EFlonk,
the number of pins needed depends on your sprayer: how many sections, rate control (manual, by +/- motor, via flowmeter), maybe boom control.
The ESP32 code supports Ethernet (not tested with actual libs) with a W5500 chip. I use this version:
If you have some more time, some guys from the developer group are about to draw a PCB. I made one for vineyard purpose (2 sections, 2 fluids, 2 pressure controls manual +/-). Feel free to build a PCB by yourself. I also did this with a prototyping board Arduino UNO format, that I put on top of an ESP32 in UNO shape.
WiFi works good, if you have a direct access to the PCs Ethernet port. Routers cause delay. My setup is like this at the moment: PC - ESP32 w5500 - WiFi (same ESP32) - section control. See:
