Microwave reflectometer for soil moisture and permittivity measurement

Microwave sensors are commonly used for aquametry measurements due to strong tendency of water molecule in absorbing microwave signals. Nowadays, meter-based microwave system is in demand as more applications need concept of being portable and simple. This thesis presents a microwave reflectometer, which operates between 2.2 GHz and 4.4 GHz. It can measure soil moisture content, m.c. up to 26 % with mean deviation between predicted and actual m.c. determined at ± 2.0 %. Five common soil samples found in southern region of Peninsular Malaysia, Johor were characterized based on macroscopic and microscopic experiments. Throughout the research, four microstrip ring resonantor sensors operating between 2.2 GHz and 4.4 GHz were designed with different angles of microstrip bends. (Conventional Sensor = 0.98 rad., Sensor A = 1.34 rad., Sensor B = 1.57 rad., and Sensor C = 1.64 rad.). Sensor B was chosen as the soil sensor. A critical study on the use of microstrip ring resonator sensors for the determination of both permittivity, er and m.c. from the measured scattering parameters (S-parameters) in conjunction with E5071C vector network analyzer (VNA) was presented. The relationship between the measured er and m.c. obtained from the oven drying method was established. From the results, it was observed that two dielectric relaxation conditions (bound and free water) exist in soil-water mixture. A semi-empirical equivalent lumped element model was created based on simulation data obtained from Microwave Office (AWR) software. The predicted er results from the model agree with the measured data using commercial HP85070D dielectric probe. The model successfully estimated er for the five common soil types with error of 2.5 %. By using inverse algorithm from the model, m.c. was predicted and was in good agreement with the standard oven drying method with its average error within ± 1.5 % for all soil samples. In general, microwave reflectometer with the proposed MRR sensor, provide nondestructive measurement for rapid determination of soil m.c. and er

Simple calibration and dielectric measurement technique for thin material using coaxial probe

This paper focuses on the nondestructive dielectric measurement for thin dielectric material using open-ended coaxial probe. The probe calibration procedure requires only a measurement of a half-space air and three open standard kits. The measured reflection coefficient for thin sample, which is backed by metal plate, is taken with a vector network analyzer up to 7 GHz and the reflection coefficient is converted to relative dielectric constant and tangent loss via closed form capacitance model and simple calibration process

Development of Compact P-Band Vector Reflectometer

A compact and low cost portable vector reflectometer is designed for a reliable measurement of reflection coefficient, S11. This reflectometer focuses on return loss measurement of frequency ranges from 450 MHz to 550 MHz. The detection of magnitude and phase is based on the utilization of surface mount Analog Devices AD8302 gain/phase detector. The data acquisition is controlled by using Arduino-Nano 3.0 microcontroller, with the use of two analog to digital converter (ADC) and a digital to analog converter (DAC). One port (Open, short and matched load) calibration technique is used to eliminate systematic errors prior to data acquisition. The evaluation of the reflectometer is done by comparing the result of the measurement to that of vector network analyzer

A review of microstrip antenna designs for TV white space applications

A review on prominent microstrip antennas fabricated for TV White Space applications is presented. This paper will delve into some of the most notable microstrip antenna designs in this frequency band that have come up in recent years. They will be analyzed to identify their strengths and weaknesses, and feedback is provided on their perceived usefulness. These antennas are designed with specific intentions, such as being placed in areas prone to harsh weather, or for long distance communications. One of the most recent antenna types to enter mainstream discussion is the microstrip patch antenna, which can easily be altered to fit various applications. Methods of connectivity such as TV White Space are enthusiastically used in various applications pertaining to connectivity and various microstrip antennas have been designed for this purpose. A conclusion was reached on the compact shorted printed monopole antenna being the most plausible choice from the antennas that have been considered and discussed

Basic Home Automation Using Smart Sockets with Power Management

The power generated in today’s time is dominated using fossil fuels that may get exhausted within the coming decades. Monitoring and management of the energy consumption hold a prime standing due to the discrepancy between power demand and production. Power meters are a part of every household, which provides us with a measurement of the overall power consumed in units. The problem with them is that they do not provide us with the individual consumption of an electrical appliance leaving customers unsatisfied with the electricity bills. This paper presents the design and application of a smart power management system (SPMS) using a variety of sensors combined with an Arduino microcontroller. This will be replacing conventional home sockets with smart sockets, allowing us to cover the monitoring, control and safety aspects of any individual appliance in the house. This system is based on a newly evolving field worldwide, called the Internet of Things (IoT). The SPMS will be measuring the current, voltage, power factor and power consumed. Along with these measurements, it can also control the power state of the device and help protect against overvoltage and overcurrent. This is basically a home automation system, in combination with smart power management, all controlled and monitored by our smartphones. The edge this device has over conventional energy monitoring systems is that it allows the user to have an exact idea of individual power consumption plus the billing on a daily basis and take measures to reduce it

Integration of Altimeter and GPS Sensors on IoT-Based Drone Delivery System (DDS)

As the trend of online shopping increased, the demand for cheaper and quicker delivery became apparent. Hence, the proposed IoT-based DDS is targeted as an alternative to decreasing the price and time taken to perform the delivery operation. This system will extract the current altitude and position of the drone via the MPL3115A2 altimeter sensor and GY-NEO6MV2 GPS module attached to the drone. The ESP32 NodeMCU would collect sensor measurement and transmit this information to the cloud server hosted on AWS EC2 virtual machine wirelessly via Wi-Fi. The recipient and operator can access the dashboard through the cloud server to perform operations such as tracking, registering, confirming, and dropping parcels. The servo motor attached to the drone would automatically facilitate parcel dropping through a simple release mechanism

Vision-Based Monitoring (VBM) for Plant Quality and Control System

This research paper designs and implements a prototype of VBM system by using a line follower robot car for indoor hydroponic plant monitoring. The proposed robot car was using line following IR sensors to follow the track line. The robot car controlled by Arduino Mega 2560. The robot is connected to Raspberry Pi for image processing purpose. The image processing can be archived by implementing the object surface area measurement method. The python module OpenCV, Numpy, matlabplt, glob, docx and OS were involved for image preprocessing and surface area calculation respectively. Hence, a document in pdf format will generate and send to the NAS system through WiFi. In fact, more actions can be taken as saved the result in PDF format as other workers able to view the entire results, taking some actions for example add on comments, signing and recording. Therefore, the document copy on board will be deleted to reduce occupied memory resources. The NAS system was builded by Raspberry Pi and a hard disk. It is connected to router via ethernet cable to gain stable internet connections. After that, the workers can link the NAS folder and have review on their desktop remotely

A comprehensive review on PV configurations to maximize power under partial shading

Partial shading is the condition where PV array experiences different level of irradiances on it which results significant reduction in output power. To handle that issue, PV modules are connected in various configurations as reported in the literature. Different connection schemes of the PV modules provide alternative paths to current flow that eventually improve power attainment under partial shading. A comprehensive study of literature shows that PV modules are connected under different schemes namely simple series (SS), parallel (P), series-parallel (SP), total-cross-tied (TCT), bridge-linked (BL) and honey-comb (HC). In this paper, a comprehensive review is performed to highlight the advantages and limitations of each scheme. To validate the findings from literature review, several experiments are carried out on various configurations in MATLAB Simulink. Three different cases namely unshaded, corner shaded and centre shaded conditions are used in the experiments to analyse the output characteristics. The superiority of various configurations in distinct operating conditions is demonstrated by comparing their maximum power output, relative power loss and fill factor. Based on the results, several recommendations are made on how to handle partial shading by using different PV configurations

Study of LED Radiation Effects on Insect Phototaxis Response for the Development of Light-Based Pest Trap

: Commercial agriculture is a resource intensive industry that employs significant amounts of agrochemicals to maintain a high yield output. Excessive application of insecticides has detrimental impacts on human health, environment and long-term sustainability. One particular area of interest is in exploring how insects are attracted to specific bands of the visible light spectrum. This paper details the study of several light conditions using Light Emitting Diodes (LEDs) to determine its phototaxis response on the common grasshopper, garden moth and lava beetle. The results conclude that all three insects exhibit positive phototaxis response on wavelengths around 491nm and below, which encompasses ultraviolet, blue and green. The radiant intensity experiment revealed a threshold response of 2.8mW/m2, or 25m in reciprocal distance

Design and Analysis of a Practical RMS Power Detector Using Power MOSFET

Power detector chip design and fabrication have experienced significant advancement with the emergence of various technological processes such as BiCMOS and CMOS. With the continuous downscaling of semiconductor devices, chip fabrication has become more complex and less accessible. This paper investigates the design and analysis of RMS power detectors using power MOSFET. A BSIM3 model developed from extracted parameters of the power MOSFET datasheet was employed to design and simulate the RMS power detector. A cascode structure with a current-source load was used to realize high conversion gain and sensitivity. RMS detection is realized by exploiting the square-law principles of MOS transistors in the strong inversion region. The proposed RMS detector targets practical applications in the agricultural sector and educational institutions. The RMS power detector was fabricated using FR4 PCB substrate. The measurement results at 2 GHz suggest that the RMS power detector employed using power MOSFET on FR4 PCB substrate can detect RF power