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An alternating current (AC) driven strain gage bridge amplifier system is developed for torque measurement in a brushless motor test bench. AC excitation of the strain gage bridge is applied instead of commonly used DC voltage, and an AC-signal conditioning dual-phase lock-in amplifier is developed using AD630 balanced modulator-demodulator for synchronous detection together with three-pole active Butterworth filter. Thus, lower levels of excitation voltage and lower self-heating of the strain gages are achieved allowing for measurements in very low ranges with high resolution (of about 0.1microstrain/0.05μV/V). The measurement system is controlled in a LabVIEW programming environment through high resolution data acquisition (DAQ) system. Additionally, in the test bench the angular velocity of the mechanical shaft and electrical power data are measured. So the mechanical power data can be compared in real time with the energy consumption and other significant variables. Using this "Power Efficiency" information a number of optimization problems can be solved. [ABSTRACT FROM AUTHOR]

In this paper the problem of illumination control in a lighting system with networked lighting devices is examined. The luminaries have fluorescent light sources dimmable by a local controller. The optimal dimming values are calculated according to the user and legal requirements for illuminance of different workspaces and their actual illumination levels are measured by light sensors. A closedloop lighting device control algorithm is used for obtaining the set illumination values. So a distributed and energy optimised illumination control with the use of daylight can be effectively implemented. The proposed approach is evaluated in lecture rooms and office environments. [ABSTRACT FROM AUTHOR]

Air conditioning in buildings is vital for people who spend much of the day indoors. The climate control industry views indoor air quality as a measure of temperature, humidity, and amount of volatile organic compounds. This paper introduces the concept of a Wi-Fi based measurement system that is tiny and low cost and works on battery power. Sensors for measurement of temperature, humidity, absolute pressure and air quality are mounted on the board. The node is able to read sensors and send data to the network by using an IP-based application protocol. [ABSTRACT FROM AUTHOR]