Design of a System for Individual Microsprinkler Control
A new microsprinkler system was developed to allow spatially variable delivery of water and fertilizer. A prototype was installed along 50 trees in a nectarine orchard. Individually addressable microsprinkler nodes were located at each tree, and a drip line controller that stored the irrigation schedule and issued commands to each node was installed at one corner of the orchard. Each microsprinkler node included a standard microsprinkler emitter, latching solenoid valve, and control circuit. A master computer allowed remote access to the drip line controller using a wireless modem. Tests were conducted to evaluate power consumption, valve and communication reliability, wireless range, and individual microsprinkler control. A lead-acid battery with solar charger powered the system for ten continuous days with no decline in average daily voltage. While testing prototype reliability, four communication errors and three valve errors occurred out of 10,250 operations. Wireless communication range between the master computer and drip line controller was 600 m with line-of-sight and 130 m with obstructions. The ability to provide microsprinkler control at the individual tree level was demonstrated by operating the emitters for different durations.