Capacitive sensing algorithm for elderly activity detection scheme indoor environment

The aim of this research is to assist elderlies in accomplishing their everyday tasks through facilitating their home atmosphere with sensors, actuators, and computational resources. A significant effort is needed to incorporate them to make them effective in daily life. Particularly, the tracking and detection of elderly people’s daily tasks, associated with the information of the user's location in the home environment signify the key pillars of this work. The detecting and tracking algorithm uses the sensory data to indicate an associated situation in order to allow elderly people with special requirements. Monitoring the elderly’s behaviour over a long period of time will allow prediction of their forthcoming alarming situation which allows the finding of the elderly’s behavioural deviations in their everyday routine. The proposed resolution has been methodically assessed in the laboratory

RC circuit response

RC circuit consists of a resistor and a capacitor which are connected in series. This chapter focuses on how the voltage develops (or shrinks) with a constant voltage source, V, is turned on (or off). Generally speaking, a capacitor accumulates charge for a current flow in, and obviously current flow out of a capacitor results into charge depletion. The current flow into an uncharged capacitor is maximum, equal to VIR at the instant in time when the circuit is closed, alternatively we can say that an uncharged capacitor acts like a short circuit at t=0. However, current flow drops exponentially to reach zero when capacitor gets fully charged to act like an open circuit. Capacitor unlike a resistor from an electrical view point shows more complex current-voltage relation. Also, besides being a charge storage element, capacitor is like a delay element too with a time constant given by r=R

HIGHLY SENSITIVE TIMER-BASED RESISTANCE DEVIATION TO TIME CONVERTER

Based on an inexpensive popular precision timing chip 555 timer, a resistance to time converter is proposed in this paper which is indeed capable of converting resistive and capacitive changes into pulse widths of proportional durations. This converter exhibits a compatibility of wider conversion range with a reasonable level of sensitivity required for industrial applications. The circuit is expected to have utility in oil and water supply schemes. Simulated results are shown to be compared with mathematical derivations, both reporting a good level of resemblance and similarities

Magnetic properties for magnetic transducer

Knowing the basic terminology for describing magnetic effects and properties are essential since magnetic materials can be used in inductive sensors as in the form of core. The various types of magnetic behaviour and properties of hard and soft magnetic materials (used in inductive sensor) need to be identified in order to decide on the appropriate applications in biomedical and industrial fiel

Analysis of phase detection circuit for human activity

This paper describes a method for analysing and detecting the daily activities of a person with the help of phase sensitive detector analysis. The phase sensitive detector (PSD) is implemented in the circuitry to measure the phase and amplitude change produced, I and Q, hence the amplitude and the phase of the voltage. The basic components of PSD analysis are modulation, multiplication and low pass filter. This technique will be able to distinguish a person's daily activities such as walking, fall events, entering or leaving a room by comparing the amplitude and phase of the output results to the input amplitude and phase change. A detailed analysis is carried out, which reveals equations that can assist in measuring the phase and amplitude information. Furthermore, MATLAB simulation results offers consistent results when compared with theory, hence, this determines the suitability of the model proposed. Likewise the data obtained can aid in the ability to analyse the movement of the person

Basic concept of inductance for inductive transducers

Inductance is a property exhibited by a circuit element, called inductor. This property is a result of a changing magnetic field associated with a coil of given number of turns wounded on air core or core of some materials. Accordingly inductance depends on the geometrical dimensions, and the turns and the core used. Invariably the most important cause for a magnetic field is the current flowing through the turns. If current is varying with time, the magnetic field is varying with time. A time-varying magnetic field includes a voltage in any conductor linked by the field, and as a result the coil causes a drop in the voltage applied. The circuit parameter of inductance displays a dormant behavior for a continuous current flow. The coil breaks its non-dormant behavior open when the current flow experiences a chang

Application and case studies of magnetic induction

The on-going development in the field of sensors applications has opened up several possibilities for significant improvements in the advancement of bio-implantable devices or medical equipment. Some researchers have designed and developed inductive sensors for various applications such as tongues drive system enabling a person with severe disabilities to sense. It determines users' intentions by tracking the movements of a permanent magnetic tracer wirelessly that is secured on their tongues using an array of magnetic sensor

Magnetic hysteresis theory :application perspective

Magnetic materials are generally categorized into two categories, soft or hard. Soft magnetic materials are characterized by large permeability and very small coercivities while the hard one are frequently used in permanent magnet applications and are characterized by large saturation magnetizations and large coercivities. Soft and hard magnetic materials have been' introduced in many applications over last few years. Applications utilizing soft/hard magnetic materials offer both economical benefits and design flexibility. A wide range of magnetic performance requirements can be met via hysteresis loop through the proper choice of materials and the appropriate processing of those material

A QUALITATIVE ANALYSIS OF BIOMASS FLOW SENSING BEHAVIOR USING CAPACITIVE TECHNIQUE

Flowsensing technology from today’s application perspective has gained significant research interest over the past few years. Among the existing sensing techniques, electrostatic and capacitive sensing techniques have proven promising although cable capacitance and stray capacitance cause inaccuracy while measuring very small capacitances. The existing measurement circuit model is complicated and has flawed electrode arrangement. By sensing very small capacitive variation, the developed capacitive technique has proven capable of reducing the stray and residual capacitance effect by using an interface sensing circuit based on circular and semicircular shaped electrode and modified capacitive bridge. The proposed interface circuit is simulated via PSPICE for realizing the small capacitive variation with permittivity variation. Hardware implementation is carried out using a flow sensing set up that senses two kinds of biomass flow variation as a change of dielectric permittivity under room conditions. The output voltage has been reproduced as a representative of the flow. Moreover, a comprehensive investigation into experimental data shows an agreeable level of consistency with the simulation results. KEYWORDS:  electrodes; sensing; capacitance; electrostatic; piping; measuremen

Output control devices : actuators

The wide spreading applications of aclUalon have opened up sevcf1l1 possibililie; in R"Chrdcat areas. The basic difference belWeen scnsor (e.g., thelll1Oll1Cler) and actuator can be simply referred as: sensor is able 10 measure a signal or stimulus obtaining infonnalion from the -real world- whereas aeruatoc itself can generate a signal or stimulus (see Figure 1.1). In Olher word, a transducer ean conven a physical phenomenon into an electric signal while an aeruator can convcn an electric signal 10 a physical phenomcno