Atika Arshad

High quality acquisition of surface electromyography – conditioning circuit design

The acquisition of Surface Electromyography (SEMG) signals is used for many applications including the diagnosis of neuromuscular diseases, and prosthesis control. The diagnostic quality of the SEMG signal is highly dependent on the conditioning circuit of the SEMG acquisition system. This paper presents the design of an SEMG conditioning circuit that can guarantee to collect high quality signal with high SNR such that it is immune to environmental noise. The conditioning circuit consists of four stages; consisting of an instrumentation amplifier that is used with a gain of around 250; 4th order band pass filter in the 20–500Hz frequency range as the two initial stages. The third stage is an amplifier with adjustable gain using a variable resistance; the gain could be changed from 1000 to 50000. In the final stage the signal is translated to meet the input requirements of data acquisition device or the ADC. Acquisition of accurate signals allows it to be analyzed for extracting the required characteristic features for medical and clinical applications. According to the experimental results, the value of SNR for collected signal is 52.4 dB which is higher than the commercial system, the power spectrum density (PSD) graph is also presented and it shows that the filter has eliminated the noise below 20 Hz.

An activity monitoring system for senior citizens living independently using capacitive sensing technique

With the continual increase of senior citizens more resources are required for providing care centers services. The quality of such services can be enhanced by remotely monitoring senior citizens living independently in their homes. The monitoring can be performed using various types of sensors, but the solution presented in this paper is simple, cost effective as well as easy to implement compared to most of the existing systems. The proposed system uses capacitive based sensor to monitor the daily activities of an elderly living alone. The monitoring system works on the principle of measuring the disturbance in the electromagnetic field when a human body approaches the sensor. This proposed sensor is fundamentally based on electric field sensing using sensors are in the form of thin planar electrodes. The Arduino-based board in combination with CapSense library acquires the sensed data. The detection system is embedded on the care-center floor surface, making the system to be non-intrusive as well as maintaining the privacy of the user. The data so obtained is perceived as information on a PC, which can be used in generating an automatic alarm system. A notification can be sent to the cell phones of the caregivers for assistance. The important thing in the alarms is that no user input is required from the person under monitoring and no devices need to be worn. A prototype sensor is described in detail and preliminary results are presented based on simulation and experimental procedure.

Resonant coils analysis for inductively coupled wireless power transfer applications

This paper proposes Wireless Power Transfer (WPT) system, consisting of transmitter-receiver coils along with some conditioning and stabilizing circuits. The transmitter circuit is designed with a simple H bridge circuit to supply the pulses to source coil. The efficiency variation or performance with respect to the coil size has been demonstrated in this paper, which is not well demonstrated experimentally in the past. It is about an inductive link efficiency calculation as a function of the geometrical dimensions. The efficiency has been derived analytically, and analytical results are validated experimentally. From the results observed the effect of geometrical dimensions (area, distance, shape, and size) is explored. The performance analysis evaluated analytically against experimentally, infers that the inductive coupling with same sized coil has achieved maximum power transfer wirelessly, for a shorter distance with applied input voltage of 24 V at resonance frequency of 180 kHz. This proposed system is practically tested for applications such as charging of devices or providing wireless sensor networks with energy supplied. The results have got useful utility for Electric Vehicles automobile industry.

Modeling of inductive coupling transducer for activation of low wattage electronic implants

A wireless power supply system based on inductive coupling approach has been developed for implantable biomedical devices that achieves excellent transducer performance by obviating the need for electrical connectors. In this paper, we report in detail the modeling and electrical analysis of an inductive power link for activation of microwatt electronic implants. As the biomedical application requires a safe and clean source of energy to power their operation, the implantable device sourced this power from an astable timer circuit in this system. The system is integrated with a 555 timer connected in astable mode, an inductive sensor, a receiver coil (represented by the secondary winding of transformer), a transmitter coil (represented by the primary winding of transformer) and a monitoring device.

Investigation of inductive coupling approach for non-contact bidirectional transfer of power and signal

Powering implantable low wattage biomedical devices and sensors through non-contact means is on the rise over the past recent years. In view of that, inductive coupling is currently the most favorable means of transferring energy for powering the low wattage implanted devices. The wireless inductive link works as an energy link to power up remote devices and also acts as a communication link to retrieve and write data to the same remote device by using the same set of inductive coils. This paper proposes an op-amp based inductive coupling circuit in order to analyze the magnetic coupling of two coils which can be applicable for the activation of microwatt electronic implants. The inductive powering system is incorporated with an op-amp circuit connected with an inductive sensor constructed by a receiver (embodied by the secondary winding of transformer), a transmitter coil (represented by the primary winding of transformer) and a monitoring device. Moreover this paper also discusses on some design considerations of the inductive power link and evaluates the work mathematically using MATLAB.

Health and Wellness Monitoring of Elderly People Using Intelligent Sensing Technique

The work aims in creating a monitoring system for the elderly population intended to be used in the bedroom. The sensors selected can measure the sleep pattern and selected vital signals. This particular sensor was preferred as a result of its simplicity in integration, cost-effectiveness, and reliability. The suggested work is shown to be in the form of embedded sensors integrated in the bedroom. An alarm system has also been included in the bedroom design to assist the elderly to request for help during an emergency situation. Bed sensors are installed under the bed sheets to detect the sleeping pattern of the elderly person. Furthermore, humidity and ambient temperature sensors are also implemented in the design to constantly monitor their vital health conditions. Thus, the bedroom health and wellness monitoring system will allow an elderly person to stay independently in their own home in a secured environment.

Automated person tracking using proximity capacitive sensors

A proliferating concern has been growing on the development of non-contact sensing and monitoring of human activities in health care sectors to avert accidents of elderly patients. Keeping in mind the limitations of the existing techniques, a novel sensing technique for human movement recognition has been proposed in this paper which uses capacitive proximity sensors. This paper works towards setting the stepping stone of implementing capacitive sensor for a living style profile through MATLAB simulation. The output response for various capacitance values is plotted here proving its utility for precise measurement of voltage which is proportional to the electrical properties of patients body at the sensing elements of the sensor. The output values measures the phase shift as a depiction of human movement. With the presence of a human body near sensor, signal waveform rises at a certain frequency peak and the movement of human body away from the sensor shows otherwise. The preliminary simulation result obtains accurate phase shift variations at a point frequency which is fruitful in further studies and reaching the ultimate goal of persons movement and activity tracking.

Experimental evaluation of agricultural biomass flow sensing behaviour using capacitive technique

To enhance industry control quality level as well as uphold enterprise economic benefit precise sensing and measurement of biomass flow is a major concern among researchers worldwide. Keeping in mind the shortcomings of existing sensing technologies this paper has developed a capacitive sensing method by making use of aop amp based bridge circuit along with particularly designed sensing electrodes. The objective of this work is fulfilled via experimental validation through a prototype hardware implementation of a flow sensing set up. The experimental results have specified the measurement system which is able to sense flow variation as a change of dielectric permittivity of different biomass materials under room condition. Moreover, the obtained results have revealed distinctive features clearly signifying the shapes and physical characteristics of electrodes, locations of the mounted electrodes on test pipe wall, dielectric permittivity and characteristics of test biomass materials.

A Comparative Study of Small Voltage Rectification Circuits for Implanted Devices

Biomedical implants have acquired an invulnerable and significant importance over the recent years due to their low voltage requirements and trifling dimensions. Biomedical implants are being widely employed for the continuous monitoring of intended parameters as well as stimulation of target organs in patients body. Being low power devices, the continuous powering without using battery dependent sources necessitates the alternative sources such as energy harvesting from the surroundings. Harvested output needs to be processed before using it for powering purposes, particularly in harsh and challenging premises. Even after processing, it needs to be made robust against the contiguous hazards so that maximum power is transferred to the load. A rectifier is employed to make this harvested energy usable. This paper compares the rectifier circuits, comparing their simulation output in terms of regulation, stability and power transferred. The rectification of small voltages is usually confronted by the threshold voltage drops that affect the output causing an effective drop in the power transfer efficiency and other parameters related. The solution to this problem has been suggested comparing the previous approaches with some modifications. Obtained results have been plotted in terms of ripple factor comparing them with the analytical calculations in order to show the role of capacitance in the reduction of ripple factor.

A pressure sensor based inductive transducer designed for biomedical applications

This paper presents an inductive pressure sensor which can be employed for the acquisition of biomedical signal, and these signals can be extremely vital in monitoring and diagnosing human body conditions. Based on the nature of the application, such implementations require precise and real time measurement for measuring any biomedical parameters. The proposed inductive pressure sensor is based on the basic principle of producing inductive changes in response to the movement of a core towards a coil. Using the inductive coil, the physical parameter that is the movement of iron core is translated into a signal with proportionate output frequency change. This type of sensor offers some important criteria like high level of linearity and sensitivity. The proposed pressure sensor can be very effective as it can be used in many biomedical applications.