A low-cost water sensing method for adaptive control of furrow irrigation

A computer-based optimization technique for furrow irrigation depends upon a network of water sensors to detect the water advance in the initial phase of the irrigation. This paper describes a new type of low-cost water sensing network developed specifically for this technique. Each sensing network consists of up to fourteen simple water sensors baked using inexpensive twin-wire. The distance between the computer and the last sensor can be up to 1000 m. Each sensor uses the variation of capacitance to detect the presence of water and communicates its state to the base computer by means of variable-frequency current pulses