Design of automatic irrigation system for orchard based on wireless sensor network

To solve the problems like high cost of water-saving irrigation system，limited lifetime of wireless sensor node，no long-term reliable operation and other issues for orchard irrigation，this paper introduced a orchard automatic irrigation system design based on wireless sensor network node. The system consists of a master node，sensor node and pump nodes. By selecting the appropriate power，solar panels and solar battery charging chip of lithium rechargeable batteries，the system effectively extends the life of the sensor nodes to achieve continuous system stability. In an open area，the effective communication distance is 208 m，node rated voltage is 5 V，operating current is 125 mA，standby current is 1.6 mA，and solar average charging current is 20 mA. Without charge，for waking up 24 times a day with frequency of 20 s，sensor nodes can work for about 60 d. In the case of connecting solar panels，rechargeable battery ensures more than power consumption. Test in orchard shows that，the sensor nodes consume the maximum power for the collection of soil moisture information. Under the condition of connected solar panel，battery voltage fluctuates within a small range of rated voltage. Randomly changing the soil moisture of irrigation area，the system can autonomously control the working status of pumps and valves battery according to the upper and lower limits of soil moisture，to meet the automatic irrigation demand