IoT for Plants

Researchers in Greece have found a way for plants to let farmers know when they need to be watered. Using lemon trees as models, they have created an FM network of sensors and receivers that enables them to “listen” to the moisture levels in the plants using inexpensive, low-power components.

An antenna attached to a lemon growing on a tree receives a signal from an existing FM radio station. This signal is passed to a transistor which is modulated by a humidity sensor inside the lemon. If the moisture level is high, the humidity sensor switches the transistor on and off at a low rate; if the moisture level is low, it switches the transistor at a higher rate. The antenna then broadcasts the transistor signal to a radio receiver, which can be located on a mobile phone, to let farmers know when they require watering. Multiple sensors at various locations within a grove of trees could even be used to optimize water levels for variations in the soil and reduce overwatering.

The researchers used FM rather than other technologies like Bluetooth to reduce cost and power requirements. By “borrowing” existing electromagnetic signals and re-modulating them, the electronics can be made simple and small enough to be powered by a lemon.

The developers have applied for a United States patent on the innovative technology which could empower a new level of monitoring in the field of agriculture.