1.Introduction of Smart Irrigation System

Smart irrigation system, also known as intelligent agricultural irrigation tecnology, is to ensure that the crop water demand under the premise of realizing water conservation and put forward a set of solutions. Smart irrigation system simply means that agricultural irrigation does not require human control, the system can automatically sense when the need to irrigate, irrigation, how long; the system can automatically turn on the irrigation, you can also automatically turn off the irrigation; can be realized when the soil is too dry to increase the amount of sprinkler irrigation, too wet to reduce the amount of sprinkler irrigation.

2.Smart irrigation system function design

Smart agricultural irrigation system to realize the above functions should make full use of the control role of the programmable controller. The system must have soil moisture sensor to realize the function of automatic sensing soil moisture. To realize the irrigation water amount of more and less adjustment, there must be a frequency converter. In the programmable controller pre-set 50% -60% RH for the standard humidity, the sensor collected humidity analog signal converted into digital signals by the A/D module.

Aiming at the low utilization coefficient of irrigation water, an embedded intelligent irrigation control system is proposed in the paper. The wireless sensor network collects crop water demand information in the irrigation area, aggregates it to the gateway nodes and sends it to the main control center, which determines the irrigation status and calculates the irrigation water quantity according to the information and controls the irrigation equipment to realize intelligent irrigation; Internet administrators have the right to manage the system remotely, which meets the needs of large-scale irrigation. The system combines wireless sensing, computing and network communication technologies to solve the key technical problems of precision agriculture.

Smart irrigation system involves a variety of high and new technologies such as sensor technology, automatic control technology, computer technology, wireless communication technology, etc. The application of these new technologies has laid an important foundation for the transformation of agriculture from traditional labor-intensive to technology-intensive.

Agricultural irrigation systems can optimize water use based on plant and soil type, amount of light, and also monitor soil moisture after rain. Some studies reality that irrigation systems can save 16 to 30 percent of water at about the same cost compared to traditional irrigation systems.

3.Smart irrigation system working principle　

Intelligent irrigation system work, the humidity sensor to collect the dryness and humidity signal in the soil, the detected humidity signal through the A/D module conversion, the standard current analog signal is converted to humidity digital signal, input to the programmable controller. Programmable controller is pre-set 50%-60% RH as the standard humidity value, the actual measured humidity signal and 50%-60% RH comparison, can be divided into: in this range, beyond this range, less than this range of three cases.

The programmable controller passes the control signal to the inverter, which adjusts the speed of the motor accordingly to the humidity value, and the motor drives the water pump to draw water from the water source, and the solenoid valve opens automatically when it needs to be irrigated, and transfers water to the nozzles through the main pipeline and the branch pipeline, and the nozzles rotate automatically at their respective rotation angles. The solenoid valve closes automatically at the end of irrigation. In order to avoid far away from the water source nozzle can not be supplied with enough pressure, in the solenoid valve on the side of the installation of a pressure gauge, to ensure that the water pressure of the nozzle to meet the set sprinkler irrigation range, to avoid the occurrence of water pressure is not enough, the nozzle range is reduced phenomenon. The whole system works in coordination to realize the intelligent control of lawn irrigation.

In summary, to realize smart irrigation, the system needs equipment such as programmable controllers, sensors, A/D modules, inverters, motors, pumps, solenoid valves, pipe networks and sprinkler heads.

4.Importance of Smart Irrigation System

Intelligent agricultural irrigation system can not only improve the source utilization rate and alleviate the contradiction of increasingly tense water resources, but also increase the yield of crops and reduce the cost of agricultural products. The irrigation system based on sensor technology is the way to develop efficient agriculture and fine agriculture.