Capacitive pressure sensors have become more popular as compared to piezoresistive pressure sensors as they yield superior sensitivity and lesser nonlinearity. Efficient analysis for modeling capacitive pressure sensors is thus increasingly becoming more important due to their innumerable use cases. The higher sensitivity of square diaphragm for the same side length in comparison to circular diaphragm makes it ideal for sensor design. In this work, a complete formulation for analysis of capacitive pressure sensor with the square diaphragm in normal and touch mode operation has been presented as these two modes are established operating modes for these sensors. A comprehensive study of sensor parameters like capacitance, diaphragm deflection, capacitive and mechanical sensitivity has been formulated to aid the choice of sensor characteristics. This work also focuses on the method to determine core design parameters for optimal operation. Computationally complex methods have been used in the past for analysis of square diaphragms. The analytical approach presented in this research is less complex and computationally efficient, in comparison to the finite element method. MATLAB has been used to compute and simulate results.

Over the recent years, the field of integrating human machine interface to power wheelchairs for autonomous driving control has gained great attention by the scientific and engineering communities. The fundamental objective of the human—wheelchair interface is to permit the individual to control the versatility of the seat in least exertion and with more vigour and security. A large variety of electric powered wheelchairs do not meet the needs of a substantial proportion of users because of requirement of muscle force and accuracy. An assistive component for executing well-heeled wheelchair motion for seriously incapacitated individuals is introduced. For making the lives of disabled people easier and less dependent, the wheelchair has been incorporated with eye control interface for the movement and direction control. For the safety of the patient, obstacle avoidance and fall alert mechanisms have been included. Also, body temperature and heart rate are two parameters that are considered for health monitoring of the patient.

Smart home security and safety systems have gained more importance in recent years. This is attributable to their significant impact in reducing and preventing loss of assets and human life. The COVID-19 pandemic adds a new dimension to home security as potentially infected people or those not taking necessary precautions such as sanitization or wearing masks may enter homes and cause further transmission. The traditional security systems are effective in conventional scenarios but require human intervention and contact which can lead to the spread of the virus. This necessitates the development of smart security systems that are autonomous and contactless. This paper presents a novel IoT enabled home security system that restricts unauthorized access and at the same time ensures that permitted users are normothermic and are following proper COVID hygiene. The proposed system is a smart edge device that does not require a cloud platform for its computational needs. Facial recognition is used to authenticate and allow approved users to get access. If an unfamiliar person tries to enter the premises, the system takes a photo, computes mask detection on the image, measures temperature and sends these three data points as a WhatsApp notification to the administrative user. The door lock can then be controlled automatically or remotely using a WhatsApp bot.

Micro-Electromechanical Systems (MEMS) based capacitive pressure transducers have a pivotal role in transducer devices for real-world applications. Thus, the efficient analysis for modelling these transducers is increasingly becoming important. These transducers use diaphragms of various geometries, however for the same active area, circular diaphragms are more sensitive as compared to square diaphragms. Pull-in voltage and touch-point pressure are two parameters which determine the performance of a micro- electromechanical systems device. In this work a complete analysis is presented for evaluating these parameters along with the mechanical and capacitive sensitivity for a circular diaphragm based capacitive pressure transducer. The effect of thickness and radius of the diaphragm has been illustrated, as they form the essential design parameters for fabricating the micro-electromechanical systems devices. Literature review suggests that relatively less work has been reported for this analysis and more complicated and computationally complex methods have been used. The semi-analytical approach presented in this research is less complex and computationally efficient, in comparison to finite element method (FEM). Critical differentiator of this formulation is related to its applicability for analysing sensor parameters with or without considering the effect of electrostatic pressure on diaphragm deflection. Furthermore, this analysis eliminates the need for determining spring constant k which is used in lumped element methods. MATLAB has been used to compute and simulate the results. The mathematical model developed is verified with a standard Finite Element Analysis (FEM) using COMSOL v5.5.