When we installed our soil moisture sensor a few weeks ago, the sensor was sending data on how much water moisture is in the soil with a sim card running on a 2G network. More recently, we upgraded the sensor to 3G. To do this, the sensor received a new microcontroller called the Electron, which is more advanced than the arduino it replaced.
In addition to this update, the data from the soil sensor is now available online. The sensor sends a small voltage into the soil every two hours, and then measures the amount of voltage that returns to the sensor. We can then look for patterns in the voltage data to figure out what amount of voltage corresponds to wet or dry soil.
Click the following link to see data from the soil sensor and a more detailed explanation on how it Click the following link to see data from the soil sensor and a more detailed explanation on how it works: http://greenstemnetwork.org/franklin-institute/