that water evaporates through the leaves’ membranes. The chip also has a cavity filled with water and a membrane through which water evaporates. As the plant’s water depletes, so does the sensor’s. When the level dips, the chip sends a signal to a data logger via a wire or a wireless transmitter to be interpreted and stored. The farmer is tipped off that it’s time to water the plants. When crops are quenched, the chip will replenish its moisture, too, and the cycle will begin anew.