Respiration monitoring of patients with chronic diseases, children, elderly, or sportsmen can be a useful tool in health condition assessment, early diagnosis of various diseases, and real-time prediction of possibly dangerous health conditions. In this paper we present a low-cost solution of respiration monitoring system, based on a custom designed capacitive sensor, which comprises of two moveable electrodes, mounted on a rigid belt attached around the person's chest. One electrode is fixed while the other one moves in a rhythm of breathing, with restriction of movement in one axis only. The electrode geometry was optimized by numeric electromagnetic simulations to provide linearity and measurable level in change of capacitance, even for case of shallow breathing. Input measuring chain is based on capacitance-to-digital (CDC) integrated circuit and it is able to capture the changes of up to several hundreds of femtofarads in full scale, with enough resolution to enable breathing rate detection, and discrimination of cases of deep, shallow, and no breathing by signal processing algorithms. The prototype measurement system was designed and tested in laboratory on several test subjects. Preliminary experiments showed that the proposed measurement system for respiration monitoring can be used for low-cost and low-power integrated solution for continuous monitoring of patient's respiration.

Phone: +385-1-6 129-977, Fax: +385-1-6 129-652, Absfracl -A prototype of a porrnhlc wireless measuring sysremfoor monitoring moror shafr torque. power and romtivnul speed was developed and restid The sysrem was designed ro offer a great /Ze.ribilir?; for wide variety of resf and research applicarions (IS well us rhe rrionitorin!: paranterer ranges. Strain gauge sensors, placed onto the revolving shufr d o n g with U \vir-eless mdiolfrequency rransmitrer, are employed 10 measure t <~r p e .Shaft mruriotml speed i.y measured by using the rotarj encoder. Torque ond power are calculared automatically on the receiver side from samples processed in U rcnl rime and displayed t o rhe ~s e r . Moreover, system provides analog and digiral outpurs oJ'the shaft vibrarion waveform for oscilloscope observing or recording IO a personal computer in a digital format. Keywords ~ Rei~olving Shufr Measurements, Srrain Gauge Measurements, Torque Meusurements, Wireless sensor.^ I. WTRODUCTIONThe most important mechanical parameters monitored on revolving motor shafts for test and meusurement purposes are torque, power and rotational speed. They contain important information about the functional performance and the motor behavior under simulated and realistic conditions. Moreover, they inay be useful to indicate possible motor problems and malCunctions in an early stage.The interconnection among these parameters is given by the formula (1):where P is the motor shaft power (kW), M the torque (kNm) and n the rotational speed (5~'). Equation (1) yields the Fact that it is sufficient to measure rotational speed and torque in order to derive motor shaft power. The appropriate sensors and transducers need to he employed to convert these quantities into electrical signals.The rotational speed is the most usually measured directly by using rotary encoders. The choice oC methods for torque measurements include strain gauge sensors, magnetostrictive trmsducers, twist angle ineasurements etc. The approach by using strain gauge sensors was chosen due to its inherent simplicity. precision, flexibility and reliability. Thc strain gauge sensors are arranged in a Wheatstone bridge circuit and mounted to the shaft, so that the one gauge measures increase o C the length in o tension direction, while the other one measures decrease [I]. Voltage mcuured by a differential amplifier on a bridge diagonal is converted to a torque value hy means of the formula (2):where Rt is a strain gauge bridge nominal resistance (R), Rx a shunt calibration resistance (kR), K, a strain gauge bridge constant. G a shear modulus (N/m2), D the outer shaft diameter (mm), Du the inner shaft diameter (mm), U, a voltage output from shunt calibration, Um0 a bridge zero calibration voltage and U the measured voltage from strain (all voltage values expressed either in (V) or AID converter digits).The approach of measuring torque on a revolving shaft by using the strain gauge sensors implies that the analog processing circuitry must be attached directly to the shaft. Moreover, the meas...

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In recent years there has been an increasing need for miniature, low-cost, commercially accessible, and user-friendly sensor solutions for wireless body area networks (WBAN), which has led to the adoption of new physical communication interfaces providing distinctive advantages over traditional wireless technologies. Ultra-wideband (UWB) and intrabody communication (IBC) have been the subject of intensive research in recent years due to their promising characteristics as means for short-range, low-power, and low-data-rate wireless interfaces for interconnection of various sensors and devices placed on, inside, or in the close vicinity of the human body. The need for safe and standardized solutions has resulted in the development of two relevant standards, IEEE 802.15.4 (for UWB) and IEEE 802.15.6 (for UWB and IBC), respectively. This paper presents an in-depth overview of recent studies and advances in the field of application of UWB and IBC technologies for wireless body sensor communication systems.

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