In this Instructable, we’re making a solar powered soil moisture monitor. It uses an ESP8266 wifi microcontroller running low power code, and everythings waterproof so it can be left outside. You can follow this recipe exactly, or take from it the useful techniques for your own projects.

If you’re new to microcontroller programming, please check out my Arduino Class and Internet of Things Class to get caught up on the basics of wiring, coding, and connecting to the internet.
This project is part of my free Solar Class, where you can learn more ways to harness the sun’s energy through engraving and solar panels.”

Link