This paper presents an efficient algorithm for distance measurement, combining both the pulse time-of-flight method and the CW phase-shift method. It copes with a low-rate sampling technique allowed by the limited bandwidth of two ultrasonic transducers working in air at 30 kHz and with modest software resources of autonomous devices. The measuring system was implemented and tested on a compact Motorola MC68HC16-based platform, with a minimum of attached hardware. Experimental results show an accuracy better than 1 mm for a poor reflecting target at a distance of about 1 m

Ultrasonic sensor distance measurements are based on the evaluation of the time-of-flight or on the determination of the phase difference between a transmitted and a received signal. Digital signal processing methods are developed in order to extract the useful information from the samples acquired from the received wave. This paper presents an efficient algorithm for distance measurement combining both the propagation time method and the phase difference method and relying on a low rate sampling technique allowed by the limited bandwidth of the ultrasonic transducers. The measuring system was implemented and tested on a compact Motorola MC68HC16 based platform, with a minimum of attached hardware. Experimental results show an accuracy better than 1 mm.

The aim of this paper is to present a new, noninvasive method to detect respiratory and cardiac rhythm disorders. We measure pressure variations within a lightly inflated cuff wrapped around the wrist, related to changes in the blood arterial pressure. By suitable numerical processing, it is possible to extract from this signal the information on respiratory and cardiac rhythms, as well as to detect and differentiate a number of sleep disorders such as central and obstructive apneas, The main ideas will be presented through exemplary results with comments

Light-emitting diode (LED) components used in lighting or backlighting applications remain operational for a long time, but in some cases, early catastrophic failures and degradation of the photocolorimetric characteristics are observed. Hence, manufacturers are highly interested in early detection of degradation mechanisms and the relationship between electrical signature evolutions and aging in order to predict the remaining lifetime of LED components. This paper describes a methodology to identify future characteristics degradation based on electrical signatures observed within the first hundred hours using an accelerating aging method. For that purpose, four kinds of high-power LEDs are submitted to temperature stress conditions that provide early aging electrical signatures. The first part of this paper describes the experimental setup and the aging protocol. In the second part, we present signatures obtained via current-voltage (I-V ) and capacitance-voltage (C-V ) data.

A white light source using direct phosphor-conversion excited by a blue laser diode is presented. In this preliminary study we have investigated the influence of phosphor’s thickness and operating current of the laser diode over the (x, y) chromaticity coordinates, Correlated Color Temperature (CCT) and Color Rendering Index (CRI). The best values found were 4000 K and 94. A 40 lm/W luminous efficacy was achieved together with a CRI close to 90 for an operating current of 0.8 A. Those values, to the best of our knowledge, were not previously reported in the literature.

In 2019, Indonesia’s electricity consumption exceeded 278 TWH, or about 1.08 MWh/capita. This value shows a considerable increase in electricity consumption which has doubled in just a decade. Previous studies have shown that the proportion of electricity consumption used for lighting needs is correlated to the country’s GDP. This is generally around 20 to 50% of electricity production but can go up to 86% in the case of Tanzania. Indonesia is the 4th country in the world in terms of population and its lighting market as well as its lighting-related energy consumption has a strong impact on several levels: societal, environmental but also economic and energy. Having a knowledge of the lamps used by the Indonesian people is therefore particularly interesting and important, in particular in the context which presents a great societal diversity but also in a context of energy saving. Indonesia is an archipelagic country made up of 5 large islands and over 17,000 small islands with widely varying levels of population density. This island geography leads Indonesia to face challenges in the distribution and production of electrical energy, which affects the use of lamps in various types of regions. The overview of this study was done by collecting data from various sources, especially BPS (Biro Pusat Statistik/Statistic Center Bureau of Indonesia), CLASP (an NGO for clean energy), the Ministry of Energy and Mineral Resources of Indonesia (ESDM), PLN (Indonesian Electrical Company), etc. The data obtained from these sources provides several descriptions of general lighting conditions in Indonesia viewed from several angles, such as growth of lamp market, use of lamp types, percentage of use of lamps with energy saving (ESL), etc. Considering that Indonesia has various regional characteristics, in this study, the survey of a total of 394 respondents was conducted on the use of lamps by creating regional categories based on electrical conditions, power consumption, and electricity per capita, among others. The categories of areas observed fall into 5 types based on their population and geography: large cities, small towns, rural/village areas, islands and remote areas. The results of compiling data from these various sources show that the types of lamps used by Indonesians follow the lighting trend in the world. The use of LED lamps has a utilization percentage of around 52%, much higher than other types of lamps such as CFL, fluorescent or incandescent. Based on the survey conducted, it is known that the widely used LED power is between 1 and 10 watts with a usage time of 8 to 12 h per day. In the next few years, it is estimated that the use of LEDs in Indonesia will increase as the government has prepared various regulations and policies related to energy saving, one of which relates to lighting.