Figure |: Data flow representation of soil health monitoring system. Before conducting the soil test measurement, the transducer was initially optimized by varying the distance between LED, reflector and LDR sensor module. During measurement, the LED and the LDR was positioned in parallel facing both in the same direction. The light gets reflected by the reflector and gets detected by the LDR. The effect of the incident light Figure 2: Block diagram of proposed model emitted to the detector was investigated to determine an optimum optical path length of the transducer. The soil test absorption measurement was conducted using the developed optical transducer with four types of soils. Two types of the soils with different nutrient were obtained from a nursery shop while the other two were taken from residential areas. The sample specification is listed in TABLE II. Each of the soil samples with optimum thickness was placed on top of the reflector under the illumination of LED lioht Figure 3: Experimental setup of soil nutrient checkup In addition to macronutrients, DHT11 which is Humidity and Temperature Sensor, which generates calibrated digital/Analog output by interfacing with NodeMCU, gives data of soil humidity and soil moisture is measured with the help of the Soil moisture sensor and the pH is measured with the help of the pH sensor. Experimental setup is shown in Figure 3. Therefore, the NPK soil content in each sample can be easily determined with only particular nutrient should be dispensed to the sample. Figure 5: Display of NPK status along with other parameters ISSN: 2321-9653; IC Value: 45.98; SJ Impact Factor: 7.42! Volume 8 Issue V May 2020- Available at www.ijraset.com
