Autonomous Sensor Networks

Wireless sensor and actuator networks (WSANs) have found many application areas and already become a part of our day to day life. Technology and standards have almost matured enough to provide the required scale of economics for the cost targets originally set by the pioneers of the field. However, both industry and researchers need to continuously develop new solutions for the challenges introduced by novel deployment scenarios. In this chapter, the applications and the challenges of WSANs are presented after a brief description of the concept.

Body area network (BAN) technology has emerged in recent years as a subcategory of wireless sensor network technology targeted at monitoring physiological and ambient conditions surrounding human beings and animals. However, BAN technology also introduces a number of challenges seldom seen before due to the scarcity of hardware and radio communication resources and the special properties of the radio environment under which they operate. In this chapter, we review the foundations of BANs along with the most relevant aspects relating to their design and deployment. We introduce current, state-of-the-art applications of BAN, as well as the most challenging aspects concerning their adoption and gradual deployment. We also discuss issues pertaining to sensor node communications, trade-offs, and interfacing with external infrastructure, in addition to important aspects relating to wearable sensor technology, enabling software and hardware, as well as future trends and open research issues in BANs.

Smart homes have developed from science fiction in the middle of the twentieth century into a reality of the twenty-first century. Initial developments were centred in the automation of comfort, energy saving and safety. More recent developments are far more ambitious, aiming to facilitate independence of elderly through the support of daily living activities and to connect the human at home with the health and social services available. This chapter refers to a variety of technologies available for the development of such infrastructures and, without aiming to be an exhaustive survey, it provides a glance at the state of the art in the area. We provide a description of systems which have been developed to assess biometrical indicators of health such as blood pressure, sleeping patterns and stress, all of which have the potential to shape up the healthcare systems of the future.

Wireless sensor networks (WSNs) are set to form a significant part of the new pervasive Internet, often referred to as the Internet of Things. WSNs have traditionally been powered by limited energy sources, viz. batteries, limiting their operational lifetime. To ensure the sustainability of WSNs, researchers have turned to alternative energy sources for power. Harvesting ambient energy from the environment to power WSNs is a promising approach, but it is currently unable to provide a sustained energy supply to support continuous operation. Sensor nodes therefore need to exploit the sporadic availability of energy to quickly sense and transmit the data. We first review the recent developments in energy harvesting technology and research on networking protocol design for WSNs powered by ambient energy harvesting. Then, we discuss some of the challenges faced by researchers in designing networking protocols and summarize the open research problems.

It has been recognised that body-centric communications (BCC) will play a significant role in 4G and subsequent technologies. BCC is an area of much interest globally, with applications in military, security, space, health care, sports and entertainment already identified. From a technical perspective, many of the problems encountered in BCC systems are relatively independent of the specific application, with some minor distinctions. In particular, space and military applications have particular requirements on robustness and extreme operating conditions that are somewhat more relaxed in other areas. The fundamental design issues are examined in this chapter from the perspective of three main areas: antennas, wireless communication protocols and sensing technologies. Examples from health care and sports applications are used to demonstrate key concepts and challenges. Current and future trends are discussed, with an emphasis on the recently released IEEE 802.15.6 wireless communications standard.

In the last two decades, many research groups and industrial companies have been and are putting much efforts in developing and using fabrics in which electronics, digital components as well as computing can be embedded. These fabrics are identified as E-textiles (e.g., electronic textiles or smart textiles). Starting from the established concept, which asserts that future systems need to be more suitably interfaced with the humans with minimal discomfort and maximum acceptability, the possibility enabled by the E-textile platforms of developing wearable and intelligent technology in terms of everyday textiles and clothes, has made them one of the most important and interesting front-end between the biological and the technological world. One field of application of these innovative textiles is the ambient intelligence, where the use of wireless system network (WSN), body area network (BAN), or wireless body/personal area network (WB/PAN) has made it possible to integrate information coming from the environment, context awareness, and the habits of people during their activities, opening new areas of research on mental and emotional status as well as human behavior in different cultural environments. This chapter is focused on the research literature of the textile-based systems and aims at showing how and where they are currently used. Starting from the textile apparel, i.e. the technology used today for their construction, the chapter reports on the characterization, integration of electronic components and, finally, briefly it illustrates some E-textile-based WBAN platforms applications on network architecture for health care and lifestyle.

Implanted sensor research has primarily been driven by the growing incidence of diabetes and the need to improve the quality of life for millions with the disease. Research to provide discreet and accurate glucose monitoring systems has a long history, culminating in three commercially available continuous glucose monitoring (CGM) systems (Medtronic, Dexcom, and Abbott). Although these systems are a significant step toward better glucose monitoring, research continues to overcome technical issues and enhance patient usability. The research includes performance improvements to current commercial electrochemical CGM, new optical-based systems in development, and long-range research incorporating unique platforms and nanotechnology. The research described only touches the surface of the ideas being percolated to solve the growing need for implanted sensors, for glucose and beyond; there are many other novel concepts incubating.

There has been great progress recently in the use of organic and carbon-based materials as the active conductors in electronic sensors for chemical species (analytes). Three principal classes of such materials are conjugated oligomers/polymers, carbon nanotubes, and molecularly imprinted polymers. These materials may be equipped with receptor subunits for analyte binding specificity, and show changed conductances when analytes bind or adsorb. There has been further advancement in the assembly of devices based on these materials into circuit elements that provide output suitable for data processing and networking. Examples of sensors based on these principles, and the mechanisms by which they transduce chemical to electrical information, are reviewed in this chapter.

Autonomous lab-on-a-chip (auto-LOC) devices are self-sustaining devices that can perform assays and report results without external cues. In this chapter, we describe the main frameworks for developing auto-LOC devices including the plug-in framework and the monolithic framework. The plug-in model aims at miniaturizing stand-alone plug-and-play components, which can then be assembled together with the microfabricated chip to develop an integrated auto-LOC device. The monolithic framework, on the other hand, seeks to integrate all components on a microfabricated microfluidic chip platform. We also highlight technologies that are relevant to portable, low-energy, and autonomous functioning of LOC devices. Finally, we present some case studies of integrated auto-LOC devices with applications ranging from point-of-care diagnostics to space exploration.

Widely accepted and deployed commodity consumer products (e.g., laptops, optical disk drives, flatbed scanners, tablets, personal digital assistants, cell phones, wrist watches) as well as high-performance components of consumer products (e.g., micromachined accelerometers, radiofrequency identification tags) present a prominent set of attractive capabilities for advanced sensors. For detection of chemical species in liquids and gases, we take advantage of previously developed, optimized, and mass-produced physical transducers, optoelectronic, radiofrequency identification, and other types of components and rationally combine them with sensing materials to produce new types of chemical sensors. This chapter presents several examples of our recent developments to demonstrate chemical sensors based on mechanical, radiant, and electrical signal-transduction methodologies.

Autonomous sensor network (ASN) node comprises of multiple miniaturized sensors, actuators, controller-circuitry and power source. Packaging and integration of these components play a critical role in determining the overall system performance, cost and time to market. Packaging of electronic components provides significant improvement in device characteristic performance and ensures long-term reliability. Packaging of ASN nodes and/or its components is more challenging, because of the sheer variety of components, like sensors, actuators, integrated circuit (IC) controllers, that make up the ASN nodes. Numerous packaging solutions like assembling individually packaged components on a single board (printed circuit board level packaging) or housing all components in a single package (system-in-package or system-on-chip approach) have been demonstrated. Some of the popular and commercially available chip-level packaging technologies are wire bonding, flip-chip bonding, tape automated bonding, etc. However the cost for these conventional chip-level packaging is much higher than other cost associated with device manufacturing. Thus wafer-level packaging has gained interest as it can be used as a low cost packaging technology. In this chapter, packaging of infrared (IR) sensors has been used as a case study to demonstrate the packaging constraints imposed by device performance and application requirements, followed by brief discussion on various packaging solutions available for individual IR sensor and more sophisticated IR sensor array. As future outlook, it seems possible to integrate all the components of ASN node, except for the battery power source. To tackle this technology constraint, energy harvesting technology has been investigated as an alternative power source. Thus replacing the battery by energy harvesters as power source is discussed at the end of this chapter.

A wireless sensing system when implemented in health-care settings can provide significant advantages over the traditional patient data collection schemes by facilitating faster response, better rehabilitation, and improved patient care. Unlike industrial and environmental sensor network systems, the application of wireless sensor networks in health care requires the use of multiple sensors on many patients. This chapter discusses implementation issues and presents details of techniques for implementation of wireless sensors in large-scale health-care environments for remote patient monitoring.

With the increasingly ubiquitous use of web-based technologies in modern society, autonomous sensor networks represent the future in large-scale information acquisition for applications ranging from environmental monitoring to in-vivo sensing. This chapter presents a range of on-going projects with an emphasis on environmental sensing; relevant literature pertaining to sensor networks is reviewed, validated sensing applications are described and the contribution of high-resolution temporal data to better decision-making is discussed.

By connecting multiple sensors, data analysis services and applications, military capabilities can be increased significantly. Consequently, wireless sensor networking has become a fundamental aspect of modern military sensor technology and military information systems. The diverse set of military use cases for wireless sensor networks is presented in this chapter in the context of intelligence, surveillance and reconnaissance, of environmental monitoring and of battlefield situational awareness.

On this basis, the characteristics of military wireless sensor networks are outlined towards operation without a pre-deployed infrastructure, for a rapid deployment of the capability, and for operation in a hostile environment. The extent to which the military requirements on wireless sensor networks go beyond commercial/civil requirements is explained. In the areas of security and sensor fusion, many well-known mechanisms deployed for the internet infrastructure are not applicable and alternative solutions are furthermore presented.

A new computing paradigm where computing platforms are aware of their physical surroundings is emerging and will be commonplace in the near future. Millimeter-scale miniature devices with sensing, processing, and wireless communication capabilities will change the way we live. These systems will provide the technology behind numerous collective sensing applications expected in the near future. Collective sensing is the collaboration between multiple networked sensor devices in sharing their readings. Through collective sensing, sensor network applications are able to provide coverage, reliability, target tracking, and continuous monitoring. Furthermore, using heterogeneous sensors, collective sensing applications can provide accurate and comprehensive view of the environment or the monitored phenomenon. This results in network intelligence that far exceeds the capabilities of any individual sensor device. This chapter covers current and emerging concepts and applications in collective sensing and discusses their future directions.