Automatic Bridge-based Interface for Differential Capacitive Full Sensing

Abstract The authors here propose, for the first time, an automatic analog interface for differential capacitance estimation, able to reveal and quantify both low and high (full-range) capacitive variations. The working principle is based on a modified De-Sauty AC bridge configuration where two differential capacitances and two resistances are employed, one of which is implemented by a Voltage Controlled Resistor (VCR). Through a suitable feedback loop, a very accurate estimation over the complete range of the differential capacitance variation is possible, while the bridge allows a continuous differential capacitance evaluation without the need of knowing the accurate value of the sensor baseline and/or its variation range. A general but very simple formula, considering both the "autobalancing" and the "out-of-equilibrium" ranges, is also given. Theoretical, experimental and simulated results are in a very good agreement. Sensitivity and resolution values, typical of sensors and their interfaces, have been determined in a practical case, showing satisfactory values

reliable and inexpensive solar irradiance measurement system design

Abstract In this work, we present an innovative low cost sensor and algorithm for the monitoring and measurement of solar irradiance. This parameter is usually estimated using pyranometers, often based on thermopile. They are quite expensive, also because need additional hardware for data acquisition and manipulation as well as non-negligible installation costs. The system architecture and novel algorithm here proposed employ small PhotoVoltaic (PV) cells and a digital sensor interface. Moreover, the logic section permits to tilt the sensor allowing to track the sun with improved accuracy

Large-signal stability of oscillators by the conversion matrix method

In this paper a method for the control of the stability of power amplifiers is extended to oscillators under large-signal conditions. It is based on the conversion matrix of the oscillator, computed from a harmonic balance simulation. This allows the suppression of possible spurious frequencies or the intentional generation of spurious signals (e.g. at sub-harmonic frequency)

A Low Cost and Flexible Power Line Communication Sensory System for Home Automation

This work focuses on the definition of a home automation system based on power line communication. A low cost and non invasive system has been developed and tested with successful results. It is based on the Cypress CY8CPLC10, an integrated power line communication chip which embeds both a PHY modem and a network protocol stack. The information management and data generation processes are demanded to a microcontroller, in this first prototype, being implemented with a standard commercial board. Combining the use of a micro controller with a power line modem and a dedicated software application it is possible to manage sensors and actuators in the neighbors through the power grid and without modifying the existing electrical and network systems

Conversion Matrix extraction by commercial CAD software for the stability design of autonomous circuits

In this paper a method to extract the conversion matrix of a nonlinear circuit by commercial CAD simulators is proposed. As an example, the conversion matrix, computed from a harmonic balance simulation, is used to control the stability of oscillators under large signal conditions. This allows the suppression of possible spurious frequencies or the intentional generation of spurious signals (e.g. at sub-harmonic frequency)

Reliable and Inexpensive Solar Irradiance Measurement System Design

Abstract In this work, we present an innovative low cost sensor and algorithm for the monitoring and measurement of solar irradiance. This parameter is usually estimated using pyranometers, often based on thermopile. They are quite expensive, also because need additional hardware for data acquisition and manipulation as well as non-negligible installation costs. The system architecture and novel algorithm here proposed employ small PhotoVoltaic (PV) cells and a digital sensor interface. Moreover, the logic section permits to tilt the sensor allowing to track the sun with improved accuracy

The effect of local vibrations on fatigue in old steel riveted bridges. A case study: the Manhattan Bridge

The present study is devoted to the effect on fatigue of vibrations induced by the train transit in an old railway steel bridge (the Manhattan Bridge in New York). It is shown how local vibrations can influence the crack growth and the remaining fatigue life of the bridge. A finite element model of the bridge is built and calibrated making use of available dynamic experimental data. Then, the actual fatigue loading spectrum is evaluated taking the actual traffic flows into account. Train transits on the bridge are simulated in order to find the structural elements where local vibrations can be significant. After having identified the members potentially subject to local vibrations, a substructure finite element model is studied for the detail. Starting from the stresses obtained in the detailed FE model, the crack growth is studied using Paris\u2019s relationship

Complete and systematic simulation tools for frequency divider design

In this work a two-stage simulation method is presented for the efficient design of frequency dividers using harmonic balance. The first stage uses a modified conversion matrix approach to select the subharmonic loads of the active element enabling the frequency division by given order N. The second stage makes use of an auxiliary generator to obtain and modify the sub-harmonic-power curve versus the input power or input frequency. Systematic simulation tools are shown to eliminate common hysteresis phenomena, which require additional constraints to minimize the disturbance of the original frequency-division bands and output power. A harmonic-balance technique to distinguish between sub-critical flip bifurcations, associated to hysteresis, and supercritical ones is presented for the first time to our knowledge. A technique is also derived to transform sub-critical bifurcations into supercritical ones. The techniques have been successfully applied to a frequency divider by 2 at 630MHz.(e.g. at sub-harmonic frequency)

Energy harvesting techniques for sensory glove systems

We proposed and addressed methods for using multiple energy harvesting strategies to power a wearable sensory glove. The capabilities of piezoelectric and thermal energy harvesters were reported, with hand motions and body heat used to these goals. A potential multi-input single-output DC-DC architecture was proposed to harvest energy from the two sources, and power analysis results were used to assess the harvesting system viability in terms of the amount of gathered power required to power the target applications