Krill: An exploration in underwater sensor networks

While sensor networks have now become very popular on land, the underwater environment still poses some difficult problems. Communication is one of the difficult challenges under water. There are two options: optical and acoustic. We have designed an optical communication board that allows the Fleck’s to communicate optically. We have tested the resulting underwater sensor nodes in two different applications

Real-time image streaming over a low-bandwidth wireless camera network

In this paper we describe the recent development of a low-bandwidth wireless camera sensor network. We propose a simple, yet effective, network architecture which allows multiple cameras to be connected to the network and synchronize their communication schedules. Image compression of greater than 90% is performed at each node running on a local DSP coprocessor, resulting in nodes using 1/8th the energy compared to streaming uncompressed images. We briefly introduce the Fleck wireless node and the DSP/camera sensor, and then outline the network architecture and compression algorithm. The system is able to stream color QVGA images over the network to a base station at up to 2 frames per second. © 2007 IEEE

Overcoming a Communication Barrier on the Way Towards a Global Sensor Network

In a global sensor network different sensor platforms will be deployed. A grave obstacle on the way of building sensor networks out of different sensor nodes are incompatible implementations of network protocol stacks used with different sensor node platforms. We describe our efforts to overcome this obstacle in a heterogeneous sensor network consisting out of MICAz Motes and Sun SPOTs, both using an IEEE 802.15.4 radio chip. We explain the major differences in the respective network stacks and our approach to bridge them. A network stack that bridges the gap between different platforms allows for more flexible and robust networks

Possibilities of monitoring cattle via GSM and A-GPS

ArticleNowadays, people and things can be localized using GNSS (Global Navigation Satellite System) or GSM technology. Devices using Differential Global Positioning Systems may not be suitable for they computing and energy intensity. The GSM and A-GPS systems have certain limitations and disadvantages. They are different in accuracy, energy intensity and therefore they are suitable for different applications. Trackers can’t be effectively used to locate animals, monitor their movements, and observe their behaviour. They can also be used to search for stolen pets and farm animals. Unguarded herds of cattle are often the target of thieves. For reasons of crime, localization was tested by devices using GSM and A-GPS technology. Specifically, the quality of these localization methods has been tested. Has been addressed above all, accuracy, reliability, speed and consistency of individual methods. In addition, further measurements were made. Localization has been tested in different well-defined environments. This makes it possible to judge the quality of individual localization technology and to suggest the best use of individual technologies and their link

Intrusion Detection In Wireless Sensor Networks

There are several applications that use sensor motes and researchers continue to explore additional applications. For this particular application of detecting the movement of humans through the sensor field, a set of Berkley mica2 motes on TinyOS operating system is used. Different sensors such as pressure, light, and so on can be used to identify the presence of an intruder in the field. In our case, the light sensor is chosen for the detection. When an intruder crosses the monitored environment, the system detects the changes of the light values, and any significant change meaning that a change greater than a pre-defined threshold. This indicates the presence of an intruder. An integrated web cam is used to take snapshot of the intruder and transmit the picture through the network to a remote station. The basic motivation of this thesis is that a sensor web system can be used to monitor and detect any intruder in a specific area from a remote location

Rope: a reactive, opportunistic protocol for environment monitoring sensor networks

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A survey on wireless body area networks for eHealthcare systems in residential environments

The progress in wearable and implanted health monitoring technologies has strong potential to alter the future of healthcare services by enabling ubiquitous monitoring of patients. A typical health monitoring system consists of a network of wearable or implanted sensors that constantly monitor physiological parameters. Collected data are relayed using existing wireless communication protocols to the base station for additional processing. This article provides researchers with information to compare the existing low-power communication technologies that can potentially support the rapid development and deployment of WBAN systems, and mainly focuses on remote monitoring of elderly or chronically ill patients in residential environments

Sensor Integration to Wireless Sensor Networks

In computer world, plug-and-play is a commonplace. In general, the sensor manufacturers use various standard physical interfaces in their sensors but they are not compatible in measurement data transfer. IEEE 1451 and ISA-100 standardization is working on common interfaces for industrial applications. The lack of standards in the field of sensor manufacturer require each sensor to be integrated individually to a wireless sensor node. This thesis presents the design of a sensor integration process for Tampere University of Technology Wireless Sensor Network (TUTWSN). The integration process eases the sensor integration, shortens the required time to integrate a sensor, and minimizes the frequency of errors and the presence of software bugs. The included documentation minimizes the loss of information in multi-partner projects. The integration process consists of five major phases: selecting a sensor, hardware integration testing, integration to a node, integration to a server infrastructure, and testing phases. The focus of this thesis is in the node and its embedded software. The integration process is tested with five sensors which are integrated to TUTWSN. The sensors are: multipurpose standard industrial signal sensor, air velocity sensor, power meter sensor, radon sensor, and piezoelectric motion detector. Two of the sensors are using I2C interface, two are using analog-to-digital converter, and one is using interrupts. Multipurpose standard industrial signal sensor required designing and calibrating the whole sensor and new software components on each level. Air velocity sensor needed a fitter sensor board for an existing transmitter and a new software application. Power meter sensor required designed and calibrating the sensor and a new software application. Piezoelectric motion detector required a new sensor and modification to motion detection application. Calibration is in all the cases done with an existing sensor and the designed sensor are calibrated according to it. The sensor integration takes less than two weeks time on average from selecting the sensor to adopted wireless sensor network. /Kir1

Practical packet combining for use with cooperative and non-cooperative ARQ schemes in wireless sensor networks

Although it is envisaged that advances in technology will follow a "Moores Law" trend for many years to come, one of the aims of Wireless Sensor Networks (WSNs) is to reduce the size of the nodes as much as possible. The issue of limited resources on current devices may therefore not improve much with future designs as a result. There is a pressing need, therefore, for simple, efficient protocols and algorithms that can maximise the use of available resources in an energy efficient manner. In this thesis an improved packet combining scheme useful on low power, resource-constrained sensor networks is developed. The algorithm is applicable in areas where currently only more complex combining approaches are used. These include cooperative communications and hybrid-ARQ schemes which have been shown to be of major benefit for wireless communications. Using the packet combining scheme developed in this thesis more than an 85% reduction in energy costs are possible over previous, similar approaches. Both simulated and practical experiments are developed in which the algorithm is shown to offer up to approximately 2.5 dB reduction in the required Signal-to-Noise ratio (SNR) for a particular Packet Error Rate (PER). This is a welcome result as complex schemes, such as maximal-ratio combining, are not implementable on many of the resource constrained devices under consideration. A motivational side study on the transitional region is also carried out in this thesis. This region has been shown to be somewhat of a problem for WSNs. It is characterised by variable packet reception rate caused by a combination of fading and manufacturing variances in the radio receivers. Experiments are carried out to determine whether or not a spread-spectrum architecture has any effect on the size of this region, as has been suggested in previous work. It is shown that, for the particular setup tested, the transitional region still has significant extent even when employing a spread-spectrum architecture. This result further motivates the need for the packet combining scheme developed as it is precisely in zones such as the transitional region that packet combining will be of most benefit