Low power wireless sensor node for human centered transportation system

Recent times world has witnessed a wireless sensing networks (WSN) technology attracting for a wide range of real-world applications, mostly due to its shrinking size and cost while demonstrating improved performances and functionalities. One of the crucial factors that affect the operation of WSN is its power consumption and battery life. This paper provides an overview for designing of a low power WSN for IoT applications. Through a combination of ZigBee wireless technology, with a strong networking function, it can realize the communication between a number of Wireless Sensor Nodes. Cost-effective and low power reliable system is implemented using this protocol. Core2530 is one of the Zigbee stack available for such network solution. While considering sensor platforms and its applications, power consumption is one of the important factors to take into consideration. This paper presents the development of low power wireless sensor node for condition monitoring of railway rolling stocks.

Problem statement: Power consumption was one of the most challenging aspects to design low power wireless sensor nodes. The objectives of the study were to (i) Design low voltage, low power transmitters for wireless sensor nodes and (ii) Compare and analyze the performance of the transmitters. Approach: The transmitters employed direct digital modulation scheme to reduce the power consumption of the sensor nodes. Emphasis was placed on observing device reliability constraints at low power to maximize the life time of the wireless sensor nodes. Results: The Amplitude Shift Keying (ASK) transmitter consumed a power of 400.104 μw from the 1.2 V supply. The Frequency Shift Keying (FSK) and Phase Shift Keying (PSK) transmitters consumed 520 μw and 5.2 mw respectively at 2.4 GHz. The transmitters suitable for low voltage, low power wireless sensor nodes were designed and implemented in 120 nm CMOS technology Conclusion: The performances of the ASK, FSK and PSK transmitters were analyzed and were compared with the previously reported low power approaches operated in similar frequency ranges.

In order to solve the problems that ever wireless sensor nodes' energy consumption is high and solar-powered wireless nodes are greatly influenced by the weather and the system is not stable, comprehensive utilization of solar energy power supply technology, sensor technology and wireless communication technology, this paper designs a new type of wireless sensor nodes, which is powered by solar energy. The wireless sensor nodes which is supplied by solar energy, solving the problem of the energy consumption of sensor nodes effectively. After tested, it has simple operation, high reliability and it can satisfy the requirement of environmental parameter acquisition and monitoring work.

Accurate timestamps of wireless frames are the basis for clock synchronization of distributed measurement devices as well as for time-based wireless localization. Wireless sensor networks (WSNs) benefit from both synchronization and localization as it enables the sensor node to fuse measurement data with temporal and spatial information. The lower communication layers of WSNs are often based on the IEEE 802.15.4 standard, whereas only for Ultra-wideband (UWB) timestamping and ranging abilities are specified. The Chirp Spread Spectrum (CSS) physical layer, recently introduced into IEEE 802.15.42011, is another promising modulation scheme for highly accurate timestamping. This paper presents a timestamping receiver architecture for 802.15.4 CSS based on a Delay-Locked Loop and subsample interpolation (chirp generation) using the CORDIC algorithm. This architecture generates arbitrary subsampleand frequency-shifted chirp templates on the fly and therefore does not require large correlation filters. Simulations of the timestamp performance show that the proposed architecture offers equal performance as post-correlation delay estimators, yet with a significantly reduced amount of multipliers. This facilitates the implementation of precision clock synchronization and localization into low-power wireless sensor nodes.

Wireless sensor node is an autonomous and compact device that has capability to monitor a variety of real-world phenomena. It is designed composed of sensing device, embedded processor, communication module, and power equipment. Wireless sensor node is part of wireless sensor network where hundred or thousand sensor node can be deployed. Over the past decade Wireless Sensor Networks (WSNs) have emerged as one of the computing platforms of note within the electronics community. In prediction, there will be more than 127 million wireless sensor nodes deployed worldwide by 2014. We have surveyed 100 currently available wireless sensor network node platforms have been developed and produced not only by the research institutions, the universities but also some companies in last ten years. In this paper, we present a review of 27 different wireless sensor node platforms. We review these devices under a number of different parameters, and we highlight the key advantages of each node platform according to dimension and power consumption. We also discuss the characteristics and trend of development and deployment a wireless sensor node technology.

Advancements in wireless sensor networks (WSNs) technologies have enabled their introduction in various application fields. A large number of these applications use sensitive data that require securing algorithms. In this paper, we present a comprehensive survey on the most commonly used security techniques in wireless sensor networks. In this survey, we also present the different implementations on numerous platforms used to realize these security algorithms with special attention to power consumption. Based upon our findings, we propose the main characteristics and parts of a new solution to realize a low power wireless sensor node with high level of security.

The sensor nodes of wireless sensor networks remain inactive most of the time to achieve longer runtimes. Power is mainly provided by batteries, which are either primary or secondary. Because of its internal impedance, a significant voltage drop can appear across the battery terminals at the activation time of the node, thus preventing the extraction of all the energy from the battery. Additionally, internal losses can also be significant. Consequently, the runtime is reduced. The addition of a supercapacitor in parallel with the battery, thus forming a hybrid-storage device, has been proposed under pulsed loads to increase the power capabilities and reduce both the voltage drop and the internal losses at the battery. However, this strategy has not yet thoroughly been analyzed and tested in low-power wireless sensor nodes. This paper presents a comprehensive theoretical analysis that extends previous works found in the literature and provides design guidelines for choosing the appropriate supercapacitor. The analysis is supported by extensive experimental results. Two low-capacity (< 200 mAh) batteries were tested together with their hybrid-storage unit counterparts when using an electronic load as a pulsed current sink. The hybrid-storage units always achieved a higher runtime. One of the batteries was also tested using a sensor node. The runtime extension was 16% and 33% when connecting the hybrid-storage unit directly and through a dc-dc switching regulator to the sensor node, respectively.

A hybrid wireless sensor network (WSN) is implemented for room temperature, humidity, and CO2 gas measurements based on the 917MHz band with a mesh network and the 447MHz band with a star connection. A duty-cycling receiver algorithm and digital temperature compensation algorithm is implemented in the receiver physical layer for designing low-power and low-cost wireless sensor nodes. The developed WSN has been constructed in a building and can provide reliable data collection with low construction complexity and low power consumption.

This paper reports the design, fabrication, and testing of a soft dielectric elastomer power generator with a volume of less than 1 cm3. The generator is well suited to harvest energy from ambient and from human body motion as it can harvest from low frequency (sub-Hz) motions, and is compact and lightweight. Dielectric elastomers are highly stretchable variable capacitors. Electrical energy is produced when the deformation of a stretched, charged dielectric elastomer is relaxed; like-charges are compressed together and opposite-charges are pushed apart, resulting in an increased voltage. This technology provides an opportunity to produce soft, high energy density generators with unparalleled robustness. Two major issues block this goal: current configurations require rigid frames that maintain the dielectric elastomer in a prestretched state, and high energy densities have come at the expense of short lifetime. This paper presents a self-supporting stacked generator configuration which does not require rigid frames. The generator consists of 48 generator films stacked on top of each other, resulting in a structure that fits within an 11 mm diameter footprint while containing enough active material to produce useful power. To ensure sustainable power production, we also present a mathematical model for designing the electronic control of the generator which optimizes energy production while limiting the electrical stress on the generator below failure limits. When cyclically compressed at 1.6 Hz, our generator produced 1.8 mW of power, which is sufficient for many low-power wireless sensor nodes. This performance compares favorably with similarly scaled electromagnetic, piezoelectric, and electrostatic generators. The generator’s small form factor and ability to harvest useful energy from low frequency motions such as tree swaying or shoe impact provides an opportunity to deliver power to remote wireless sensor nodes or to distributed points in the human body without the need for costly periodic battery replacement.

This paper presents the design and simulation of a two stage power management circuit implemented in 0:18μm CMOS that operates from very low voltages starting from 460mV and higher up to a maximum of 800mV. The proposed capacitive power management unit consumes very low power of 11μW @ 500mV sufficient to be operated from tiny photovoltaic cells, dimensions of few mm2. In addition to the lower power consumption, the proposed circuit does not need any off chip components; ideal for ultra low power wireless sensor nodes.

A scheme for WSNs (wireless sensor networks) security is given by dividing sensing tetrahedron into clusters and using the symmetric polynomials in this paper.The sensing tetrahedron is divided into a number of small grids.All those sensor nodes, both ordinary sensor nodes and heterogeneous sensor nodes are distributed in the sensing tetrahedron.In a grid, all ordinary sensor nodes and heterogeneous sensor nodes establish their shared keys through using the symmetric polynomials.All the heterogeneous sensor nodes establish their shared keys through using the symmetric polynomials.At last, all sensor nodes establish their keys directly or indirectly in the whole sensing tetrahedron.Analysis and comparison demonstrate this scheme enhances the WSN security, has good network connectivity, saves node storage, reduces network computing load, and extends the network lifetime.

One important issue in wireless sensor networks is how to gather sensed information in an energy efficient way since the energy is a scarce resource in a sensor node. Many protocols have been proposed for data-gathering between wireless sensor nodes. However, most of these protocols work on static wireless sensor networks. In this paper, we provide clustering-based and time-driven protocols which minimize energy dissipation for data-gathering in wireless mobile sensor networks where the sensor nodes are capable of mobility. We first consider the node mobility when organizing clusters. Our protocols will have a sensor node select a proper cluster-head to join in order to save energy. We then consider how to elect the cluster-heads and provide two algorithms for cluster-head election. Last, we implement all the protocols and perform the experiments for evaluating the protocols.

Healthcare solutions using anytime, and anywhere remote healthcare surveillance devices, have become a major challenge. The patients with chronic diseases who need only therapeutic supervision are not advised to occupy a hospital bed. Using Wearable Wireless Body/Personal Area Network (WWBAN), intelligent monitoring of heart can supply information about medical conditions. Electrocardiogram (ECG) is the core reference in the diagnosis and medication process. An approach on healthcare solution WBAN based, for real-time ECG signal monitoring and long-term recording will be presented. Low-power wireless sensor nodes with local processing and encoding capabilities in order to achieve maximum mobility and flexibility are our main goal. ZigBee wireless technology will be used for transmission. Sensor device will be programmed to process locally the ECG signal and to raise an alert. Low-power and miniaturization are essential physical requirements.

Smart Technologies with Wireless Sensor Networks

Proposed wireless sensor node is a highly flexible and programmable system on chip (PSoC) architecture along with integrated RF radio chip, which can be adapted to any IEEE 802.15.4 standard based protocol, working at the band of 2.4GHz.This can be accompanied by the RF antenna matched with the interface circuit for various kinds of sensors and peripherals to form a wireless sensor node.This can be very well used to form a wireless sensor network in different domains.This proposed methodology can be used for specific application for improving the WSN stability and performance.This article will mainly present the design of wireless sensor nodes based on PSoC and CyFi radio chip, including the application specific antenna and hardware design for the system on chip for the sensor node and the simple introduction of the application domain.The proposed nodes are used with a special antenna and application based protocol for communication.This design has a better power handling and performing capacity.Further, we have implemented this for the wireless sensor node as well.