Energy Harvesting and Management for Wireless Autonomous Sensors

Wireless autonomous sensors that harvest ambient energy are attractive solutions, due to their convenience and economic benefits. A number of wireless autonomous sensor platforms which consume less than 100?W under duty-cycled operation are available. Energy harvesting technology (including photovoltaics, vibration harvesters, and thermoelectrics) can be used to power autonomous sensors. A developed system is presented that uses a photovoltaic module to efficiently charge a supercapacitor, which in turn provides energy to a microcontroller-based autonomous sensing platform. The embedded software on the node is structured around a framework in which equal precedent is given to each aspect of the sensor node through the inclusion of distinct software stacks for energy management and sensor processing. This promotes structured and modular design, allowing for efficient code reuse and encourages the standardisation of interchangeable protocols

Switched Capacitor DC-DC Converter for Miniaturised Wearable Systems

Motivated by the demands of the integrated power system in the modern wearable electronics, this paper presents a new method of inductor-less switched-capacitor (SC) based DC-DC converter designed to produce two simultaneous boost and buck outputs by using a 4-phases logic switch mode regulation. While the existing SC converters missing their reconfigurability during needed spontaneous multi-outputs at the load ends, this work overcomes this limitation by being able to reconfigure higher gain mode at dual outputs. From an input voltage of 2.5 V, the proposed converter achieves step-up and step-down voltage conversions of 3.74 V and 1.233 V for Normal mode, and 4.872 V and 2.48 V for High mode, with the ripple variation of 20–60 mV. The proposed converter has been designed in a standard 0.35 μm CMOS technology and with conversion efficiencies up to 97–98% is in agreement with state-of-the-art SC converter designs. It produces the maximum load currents of 0.21 mA and 0.37 mA for Normal and High modes respectively. Due to the flexible gain accessibility and fast response time with only two clock cycles required for steady state outputs, this converter can be applicable for multi-function wearable devices, comprised of various integrated electronic modules

Wireless sensors and IoT platform for intelligent HVAC control

Energy consumption of buildings (residential and non-residential) represents approximately 40% of total world electricity consumption, with half of this energy consumed by HVAC systems. Model-Based Predictive Control (MBPC) is perhaps the technique most often proposed for HVAC control, since it offers an enormous potential for energy savings. Despite the large number of papers on this topic during the last few years, there are only a few reported applications of the use of MBPC for existing buildings, under normal occupancy conditions and, to the best of our knowledge, no commercial solution yet. A marketable solution has been recently presented by the authors, coined the IMBPC HVAC system. This paper describes the design, prototyping and validation of two components of this integrated system, the Self-Powered Wireless Sensors and the IOT platform developed. Results for the use of IMBPC in a real building under normal occupation demonstrate savings in the electricity bill while maintaining thermal comfort during the whole occupation schedule.QREN SIDT [38798]; Portuguese Foundation for Science & Technology, through IDMEC, under LAETA [ID/EMS/50022/2013

Challenges and New Trends in Power Electronic Devices Reliability

The rapid increase in new power electronic devices and converters for electric transportation and smart grid technologies requires a deepanalysis of their component performances, considering all of the different environmental scenarios, overload conditions, and high stressoperations. Therefore, evaluation of the reliability and availability of these devices becomes fundamental both from technical and economicalpoints of view. The rapid evolution of technologies and the high reliability level offered by these components have shown that estimating reliability through the traditional approaches is difficult, as historical failure data and/or past observed scenarios demonstrate. With the aim topropose new approaches for the evaluation of reliability, in this book, eleven innovative contributions are collected, all focusedon the reliability assessment of power electronic devices and related components

Disseny i construcció d'una sonda atmosfèrica

The project consists of the construction of a functional meteorological probe, controlled by an Arduino microcontroller. This probe was design to measure pressure and temperature as functions of the altitude. This device is the first of its kind built at the EETAC, thus a considerable effort of requirement definition has been done. In the present report we describe how all the probesystems were designed, and all the necessary components as well as the reason why they were chosen are described. The resulting design is modular in order to facilitate future improvements/expansions.The steps necessary for the assembly of all the components in a common structure are detailed, as well as the choice of tools and materials. All the systems developed were tested simulating conditions similar to those expected in the real mission.Finally, after the construction and validation processes, all the materials and the tasks needed to launch the probe up to at an altitude of 35 km are detailed.The present report is intended to serve as a guide for futuresimilar projects in EETAC. The resulting device from this work is named FourCast after our surnames

Design of a wireless monitoring system based on the ZigBee protocol for photovoltaic systems

This thesis was submitted for the degree of Master of Philosophy and awarded by Brunel University.This work deals with the possibility of using the promising technology of wireless sensor networks (WSN) in the field of photovoltaic (PV) plant supervising and monitoring. The knowledge of the status and good working condition of each PV module separately as well as of any component of the PV system will guide in a more efficient way of power management. This work will concentrate on monitoring and controlling as well as healthy operation control of PV panels separately. Data logging will be also available and can be used for reference or statistical purposes. The nature of wireless sensor networks (WSN) offers several advantages on monitoring and controlling applications over other traditional technologies including self-healing, self-organization, and flexibility. The versatility, ease of use, and reliability of a mesh network topology offered by the ZigBee technology that is based on the IEEE 802.15.4 standard, are used in this work to offer the maximum of its capabilities on the system being presented. A set of sensors attached on each PV panel are connected to a wireless ZigBee module. Each PV panel has its own ZigBee device located at its back side. All ZigBee devices forms a network with all the necessary devices of the ZigBee protocol included, such as end devises (RFD), a router (FFD), and a coordinator (COO). An extra ZigBee device might optionally be used to serve the whole system as an Ethernet gateway for making the system able to be connected to the internet. The factors that are being monitored are the panel‟s temperature, the output voltage, and output current. At the router device that operates as a parent for all the end devices, extra monitored factors are the air dust concentration, current irradiance and also the angle of the PV array (in the case of tracking system use).Two controlling outputs (relays) are located at the router device offering the capability of controlling the motors or the actuators of a tracking system

Concept and development of an autonomous wearable micro-fluidic platform for real time pH sweat analysis

In this work the development of an autonomous, robust and wearable micro-fluidic platform capable of performing on-line analysis of pH in sweat is discussed. Through the means of an optical detection system based on a surface mount light emitting diode (SMD LED) and a light photo sensor as a detector, a wearable system was achieved in which real-time monitoring of sweat pH was performed during 55 minutes of cycling activity. We have shown how through systems engineering, integrating miniaturised electrical components, and by improving the micro-fluidic chip characteristics, the wearability, reliability and performance of the micro-fluidic platform was significantly improved

Retention and application of Skylab experiences to future programs

The problems encountered and special techniques and procedures developed on the Skylab program are described along with the experiences and practical benefits obtained for dissemination and use on future programs. Three major topics are discussed: electrical problems, mechanical problems, and special techniques. Special techniques and procedures are identified that were either developed or refined during the Skylab program. These techniques and procedures came from all manufacturing and test phases of the Skylab program and include both flight and GSE items from component level to sophisticated spaceflight systems