Well, as my next step I built a dedicated little board/circuit/computer based around the ESP32 chip. It does the following:
- When it boots up, it connects to the WiFi in my shop
- It then connects to the Internet
- It sets its clock from a web-based NIST NTP time server
- It then runs a web server and waits for requests
- When those come in, it measures the temp, humidity, and pressure in the air compressor closet
- It reports those in the web page
- It displays the current values on a little OLED display right on the chip/board itself
For a day or so it'll still be live here:
http://1969Pontiac.com:99/
...and here's a picture of the circuit. I was thinking it could manage the actual compressor if I wanted to go down that path! I might even do so if I can find a "soft start" controller for an AC motor that I can control somehow.