Dr Sachin Gajjar
@nirmauni.ac.in
Associate Professor, Electronics and Communication Engineering
Institute of Technology, Nirma University
RESEARCH INTERESTS
Wireless Networks, Internet of Things, Embedded Systems
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Mahek Vyas, Sachin Gajjar, Manisha Asit Upadhyay, and Rajat Acharya
Wiley
SummaryIndia has developed its own regional navigation satellite system called the Indian Regional Navigation Satellite System (IRNSS), also known as Navigation with Indian Constellation (NavIC). IRNSS/NavIC provides standard positioning and timing services for civilians and restricted services for authorized users. In this paper, single point positioning is implemented on the NavIC receiver data. Estimation techniques of the least squares method and extended Kalman filter are implemented after applying broadcast‐based clock corrections, orbit computation, relative time correction, and ionosphere delay correction for single and dual frequency. A data extraction and storage module is developed to store computed parameters at every intermediate stage in separate files. This is followed by an error plotter module to plot the extracted parameters for each satellite and to separately analyze their performance and the obtained errors. The estimated receiver position is visualized on Google Earth. The absolute error in both estimation techniques ranges between 5 and 15 m throughout the period.
Nishant Sahay and Sachin Gajjar
IEEE
There are several hardware communication protocols available today, but the three most prevalent and frequently used are UART (Universal Asynchronous Receiver Transmitter), SPI (Serial Peripheral Interface), and $\\mathbf{I}^{\\mathbf{2}} \\mathbf{C}$ (Inter-Integrated Circuit). This article discusses the working, implementation and verification of these protocols. It aims to highlight the difference in hardware requirements for implementation of each of these designs, and the difference in the approach of verification of these designs. The implementation of the design is done using Quartus Prime tool. An FSM is designed for each of these protocols which is then used to write the Verilog code for the design. The design is then synthesized for Cyclone V SE Base FPGA board. The resource utilisation for each protocol is discussed based on Combinational ALUTs and Dedicated Logic Registers used. UVM (Universal Verification Methodology) based verification is preformed for each of the design. A verification environment is developed using UVM. These environments were then compiled in QuestaSim 10.7c. UVM sequences are used to create the stimuli. The verification for each protocol differs in term of the sequences that are applied. UART verification proves to be a lot more challenging because of different parameters that are configurable, such as setting the baud rate, data length, stop bits and parity types. While SPI and $I^{2} \\mathbf{C}$ have a similar type of sequences which are used for their verification, these are read, write, reset, and error sequences. However, upon implementation it can be seen that $I^{2} \\mathbf{C}$ proves to be more resource efficient.
Manan Jain, Het Kanzariya, Neel Joshi, Yesha Masharu, Sachin Gajjar, and Dhaval Shah
Springer Science and Business Media LLC
Hetal Panchal and Sachin Gajjar
Wiley
SummaryUnderwater wireless sensor network (UWSN) is a network made up of underwater sensor nodes, anchor nodes, surface sink nodes or surface stations, and the offshore sink node. Energy consumption, limited bandwidth, propagation delay, high bit error rate, stability, scalability, and network lifetime are the key challenges related to underwater wireless sensor networks. Clustering is used to mitigate these issues. In this work, fuzzy‐based unequal clustering protocol (FBUCP) is proposed that does cluster head selection using fuzzy logic as it can deal with the uncertainties of the harsh atmosphere in the water. Cluster heads are selected using linguistic input variables like distance to the surface sink node, residual energy, and node density and linguistic output variables like cluster head advertisement radius and rank of underwater sensor nodes. Unequal clustering is used to have an unequal size of the cluster which deals with the problem of excess energy usage of the underwater sensor nodes near the surface sink node, called the hot spot problem. Data gathered by the cluster heads are transmitted to the surface sink node using neighboring cluster heads in the direction of the surface sink node. Dijkstra's shortest path algorithm is used for multi‐hop and inter‐cluster routing. The FBUCP is compared with the LEACH‐UWSN, CDBR, and FBCA protocols for underwater wireless sensor networks. A comparative analysis shows that in first node dies, the FBUCP is up to 80% better, has 64.86% more network lifetime, has 91% more number of packets transmitted to the surface sink node, and is up to 58.81% more energy efficient than LEACH‐UWSN, CDBR, and FBCA.
Dhyanik Pujara, Trushti Selarka, and Sachin Gajjar
IEEE
This paper presents the development of a user-friendly weight data management system utilizing data acquisition methods. The system was designed to tackle prominent industrial challenges faced by Ocean Abrasive, an abrasive wheel manufacturing factory: (i) misinterpretation of weight or nameof grain (raw material) arising from handwritten entry in paper cards, (ii) no data logging (of weight) of constituent grains of the products manufactured, making it difficult to corroborate and repudiate clients' claims regarding inconsistencies of the products, (iii) Employment of redundant workforce. To address these three challenges, a sophisticated data acquisition system using the M5 Stack Core ESP-32 (having dimensions 54 × 54 × 16 millimeters), was deployed. Data storage of the constituent grain weight of products (wheels) being manufactured was facilitated through an SD card mounted on M5 Stack and the following communication protocols were utilized: ESP-NOW for communication between the display node and weighing machine node, Classic Bluetooth for providing input via Serial Bluetooth terminal (keyboard) mobile application, and RS232 to establish a simplex communication between weighing machine and ESP32 microcontroller. This paper outlines the design, Implementation, and outcomes of this innovative and tailored approach, which has the potential to automate weight data management by leveraging functionalities of data acquisition systems in industrial settings similar to Ocean Abrasive which might have the necessity to record data such as weight, and log the data of operation process thereby resulting into a necessity to deploy sophisticated data acquisition system. The proposed data acquisition system is user-friendly and, on average, saves 55% production time. The entire cost (one time) of the system was 5900/- Indian rupees (INR) which has anticipated a break-even point after 22 days of deployment since the labor costs were reduced by 50%.
Parth Patel, Nikhil Gupta, and Sachin Gajjar
IEEE
This Paper outlines the creation, construction, and evaluation of a Real-Time Voice Recognition System using TinyML on an Arduino Nano 33 BLE, a hardware platform with limited resources. Tiny ML consists of machine learning models that can be deployed on the low -energy and resource- constrained embedded system. Real-time voice Recognition is used in virtual assistants like Siri, Google Assistant, Alexa, speech-to-text translation, vehicle Navigation, voice biometrics, home automation etc. The work presents the implementation of real-time voice recognition wherein a TinyML model is trained using the EdgeImpulse framework and deployed on Arduino Nano 33 BLE device having a built-in microphone. The model identifies the ON and STOP keywords pronounced by the user using Arduino Nano 33 BLE device's built-in microphone which then turns on a bulb connected to it via a relay. The accuracy of the system is found to be 97 %.
Riththika Sukanandan and Sachin Gajjar
IEEE
An Electronic Control Unit (ECU) acts as a vehicle's the central hub, managing functions through microcontrollers that interpret sensor input and ensure smooth operation. Over 50 microcontrollers govern the operation of low-voltage components like indicators, horns, regenerative brakes, air conditioners, power windows and airbag deployment to monitor control, and enhance diverse aspects, such as engine and motor modules' suspension, powertrain, transmission, brakes, and body functions. This paper delves into the hardware design of an electric vehicle powered by a 48V Lithium Nickel Manganese Cobalt Oxide (Li-NMC) battery. To efficiently utilize this voltage, a buck converter steps it down to 12V for the low-voltage system, with voltage regulators further reducing it to 5V for the microcontroller board's operation. Inputs from buttons like start, brake, charge, accelerator, forward, and reverse are processed by the microcontroller board and Motor Controller. They, in turn, control various LED pins to indicate different states of the car system. The system, designed for an all-terrain vehicle, underwent rigorous testing with a Brushless Direct Current (BLDC) motor, achieving 45 km/hr and 5.16 m/s2 acceleration. The implementation uses an Arduino board and C language to enhance the vehicle functionality by enabling user interactions, such as starting the car, applying brakes, charging, and controlling acceleration, all while providing clear visual feedback through LED indicators. This paper exemplifies the potential of readily available microcontroller applications for EVs and provides a forward looking vision for an all-terrain four-wheel electric vehicle, showcasing the energy-efficient utilization of low-voltage systems through readily available electronic circuit boards.
Mahek Vyas, Sachin Gajjar, Manish Upadhyay, and Rajat Acharya
IEEE
Indian Regional Navigation Satellite System (IRNSS) is a satellite based navigation system developed and deployed by Indian Space Research Organization consisting of seven satellites with two frequencies in L5 and S bands. The positioning uses pseudorange, carrier phase or combination of both. In the receiver, loss of lock with the signal in phase measurements often results in an accumulation of integer cycles introducing an error that ultimately affects the ambiguity resolution. The aim of this work is to develop a software module for the detection of the Cycle Slips for single and dual frequency IRNSS data to detect Cycle Slips in majority of cases. Doppler Integration method and Carrier Phase combinations are used on single and dual frequency data respectively. Additionally, a Comma Separated Variable file is created to store the Cycle Slip detection flags to analyze the occurrence of Cycle Slips for available Satellites over the observation period.
Manav Chotalia and Sachin Gajjar
Springer Nature Switzerland
Hasit Trivedi, Sanjay Parmar, and Sachin Gajjar
IEEE
The whole world has been witnessing a colossal adversary in the form of Coronavirus disease (COVID-19). With its super-fast spread, it has devastated a major part of the world and found to be the most dangerous virus of the 21st Century. Most of the countries went into lockdown to control the spread of the virus, and the economy shattered. Then slowly and gradually, some workspaces, malls, and public places started opening with the strict guidelines of governments. However, the fear of COVID-19 does not allow us to get back to our everyday lifestyle. Amongst the various symptoms observed in COVID-19-infected humans, the rise in body temperature is the most common symptom. As coronavirus is highly infectious, it is crucial to avoid physical contact with infected people to prevent the virus's spread. The primary reason for the spread of the virus is a lack of hygiene and a proper system to monitor the symptoms. Thus, the development of smart security systems for early symptom identification at the entrance of public places is essential to stop transmission. This paper covers designing a smart door system that measures the body temperature without human intervention and regulates people's entry through a mechanized door using Arduino UNO Board, IR thermometry temperature sensor, PIR sensor, and servo motor. The system will open the door only if the person seeking entry is normothermic, and if a person is hypothermic, it will trigger the alert system, which will eventually prevent the transmission of the virus.
Akshat Baheti, Dev Patwa, and Sachin Gajjar
IEEE
The whole world has been witnessing the gigantic enemy in the form of COVID-19 since March 2020. With its super-fast spread, it has devastated a major part of the world and found to be the most dangerous virus of the 21st Century. All countries went into a lockdown to control the spread of the virus, and the economy dropped down to an all- time low index. The major guideline to avoid the spread of diseases like COVID- 19 at work is avoiding contact with people and their belongings. It is not safe to use computing devices because it may result in the spread of the virus by touching them. This paper presents an Artificial Intelligence- based virtual mouse that detects or recognizes hand gestures to control the various functions of a personal computer. The virtual mouse Algorithm uses a webcam or a built-in camera of the system to capture hand gestures, then uses an algorithm to detect the palm boundaries similar to that of the face detection model of the media pipe face mesh algorithm. After tracing the palm boundaries, it uses a regression model and locates the 21 3D hand-knuckle coordinate points inside the recognized hand/palm boundaries. Once the Hand Landmarks are detected, they are used to call windows Application Programming Interface (API) functions to control the functionalities of the system. The proposed algorithm is tested for volume control and cursor control in a laptop with the Windows operating system and a webcam. The proposedsystem took only 1ms to identify the gestures and control the volume and cursor in real-time.
Palak Jain, Taneesha Chaudhary, and Sachin Gajjar
IEEE
Waste management has now become a necessary practice in all countries around the world. India generates approximately 65 million tons of garbage every year. The main challenge is to manage this waste. Conventional systems are not efficient to manage this much amount of waste. IoT can play a dominant role in handling waste and making any country greener and more efficient. Time to Time disposal of waste is important and if ignored can be a health hazard. The current system for waste disposal in local areas for small and densely populated cities is inactive which causes garbage to spread all over the area. The rate of garbage generation is higher than garbage disposal. It is required to manage and dispose of the waste for a sustainable and clean country. This paper presents an IoT-enabled Waste management system for the collection of garbage. The system consists of smart garbage bins made using Ultrasonic sensors, NodeMCU, and a Global Positioning System (GPS) module. The ultrasonic sensor detects the level of garbage in the dustbin and notifies the garbage collection authorities when the dustbin is full. The SMS and email notification are sent using If This Then That (IFTTT) and ThingSpeak the online digital automation platforms. A mobile application is created using the Massachusetts Institute of Technology (MIT) app inventor where the authorities can see the status of the dustbin and an optimized shortest route to be followed by the garbage collector truck for garbage collection and disposal. The proposed system is economical, practical, easy to use, and requires minimal human interaction.
Viraj Mankad, Virag Shah, Sachin Gajjar, and Dhaval Shah
Springer Nature Switzerland
Hetal Panchal and Sachin Gajjar
Springer Nature Singapore
Rashi Gautam, Vaisvik Chaudhary, and Sachin Gajjar
Springer Nature Singapore
Vincent Abraham, Divyesh Ranpariya, Parin Parikh, Sachin Gajjar, and Dhaval Shah
Springer Nature Singapore
Samyakkumar Jain and Sachin Gajjar
Springer Nature Singapore
Sachin Gajjar, Manisha Upadhyay, Mahek Vyas, Ayushee Samridhi, and Bhavin Patel
Springer Nature Singapore
Mahek Vyas, Sachin Gajjar, Manisha Upadhyay, and Rajat Acharya
IEEE
The Indian Regional Navigation Satellite System (IRNSS) is a regional satellite based navigation system developed and operated by India covering the Indian region extending up to 1500 km around to give timing and real-time positioning service. IRNSS, also known as NavIC (Navigation with Indian Constellation) provides Standard Positioning Services (SPS) and encrypted Restricted Services (RS) for civilian users and authorized users respectively. The data received from the NavIC receiver in RINEX file format needs to go through different types of corrections to estimate the position of the receiver. In this paper, broadcast-based clock and orbit correction, relativistic correction, and dual-frequency ionosphere correction are applied to the RINEX data received from NavIC Receiver and Least Square Method is used as the estimation technique to compute the location of the NavIC receiver. Absolute errors between the actual and estimated position of the receiver and ground track are estimated and plotted. For visualization, the actual and estimated positions of the receiver are pinpointed on Google Earth. Clock error, ionosphere error, and relative error are extracted and also plotted for each satellite used in the computation (both the frequencies L5 band-1176.45 MHz and S band-2492.028 MHz) to separately analyze the obtained errors with respect to time. The accuracy by implementing Single Point Positioning is less than 10 meters.
Hetal Panchal and Sachin Gajjar
IEEE
This paper presents a Fuzzy C Means clustering algorithm for choosing the cluster head by first taking the cluster's center into account, and then relying on the nodes' remaining energy, for reliable and energy-efficient inter-cluster multi-hop routing from cluster heads to the surface sink node, Ant Colony Optimization is applied. A comparative analysis of the proposed protocol is done with the Single Hop Fuzzy Energy Efficient Routing protocol and Multi-Hop Fuzzy Energy Efficient Routing protocol. The proposed protocol outperforms SH-FEER and MH-FEER in FND up to 27.36%, in network lifetime up to 11.76%, and in energy consumption up to 25.91%.
Hetal Panchal and Sachin Gajjar
Springer Nature Singapore
Sagar Maheshwari and Sachin Gajjar
Springer Singapore
Shital Chaudhary, Sachin Gajjar, and Preeti Bhowmick
Springer Singapore
Riddhi Soni, Sachin Gajjar, Manisha Upadhyay, and Bhupendra Fataniya
Springer Singapore