Design Of Plant Physiology And Ecology Sensor

A variety of equipment is often used in agricultural production to monitor the environment that plants grow up in, so as to provide basis of decision-making for the automation control In order to determine the time node and duration for crop irrigation, we have to perceive the changes of plants’ water supply condition in traditional greenhouse by detecting temperature and humidity in the greenhouse environment. This monitoring mainly aimed at the environment inside the greenhouse, but there was a very large gap between the external environment and the real physiological demand of plants. Sensors are used in modern greenhouse to measure the temperature changes of micro-environmental temperature changes closed to the plants, so as to more accurately reflect the plants’ growth conditions, thus reflecting its water supply situation.This paper proposes a program of designing the SAW sensor a modular design scheme of surface acoustic wave sensor for the temperature monitoring of the plant foliar micro-zero, and analyzes the principle of SAW sensor. Then I have designed the sensitive module, test signal generating module, switch module and frequency detecting module to build a SAW sensor to monitor the temperature. I have done the simulation for every filter circuit, every signal generating circuit and the pulse counting circuit. After the simulation, I have made the printed circuited boards and tested the actual performance of the sensor. The experimental results shows that the sensitive module has good frequency-temperature characteristics and it’s sensitivity has reached4.59KHz/℃; the test signal generating module can generate the required signals which have almost no spurious signals; the frequency detecting module can detect frequency of the echo signal with the error at±1KHz and meet the required accuracy; the sensor’s error of temperature measurement is small which is less than0.5℃. The sensor can be used in temperature monitoring for the foliar micro-zero.Existing plant stalk diameter sensors are usually necessary to apply an appropriate preload on the measured part for successfully detecting the plant stalk. By doing this, it’s no doubt that the preload will affect the normal growth of plants. This paper presents a plant stalk sensor which depends on the photoresistor, it needn’t have to apply the preload so as to do no influence on the plant and has low develop cost. It’s the ideal choice for the monitoring of plant stalk diameter. I have also verified the feasibility of the principle through a series of experiments. The ptotoresistance has the best linear characteristic within the effective range of8.55mm under the condition of highlight at short range. The sensitivity of the sensor has reached73.4/mm. I have also designed the resistance detection module for the automatic detection of the ptotoresistance. The resistance measurement results show that accuracy of the module is high and it can be used for the detection of photoresistance. The stem diameter measurement results show that the sensor has high measurement precision with error at±0.4mm within the effective range and it can be used in the monitoring of the plant stem diameter.