John Buckley

Design, Fabrication and Testing of Miniaturised Wireless Inertial Measurement Units (IMU)

This paper will describe the design, fabrication, operation, and test results of a miniature wireless inertial measurement unit (WIMU) with a form factor of 10 mm. Many types of Inertial Measurement Units(IMU) have been designed and manufactured by prominent companies such as Crossbow, Xsens, O NAVI and Honeywell, among many others. American GNC Corporation currently claims to have the worlds smallest IMU[1]. Most of these IMUs are aimed at aerospace and other types of navigation, which is why miniaturisation has not been a priority. However, with the onset and development of MEMS technology, novel applications have been found for those MEMS sensors employed in an IMU. Head mounted displays, Segways and mobile phones are among the new products taking advantage of miniaturised MEMS inertial sensors. The current WIMU development is a step along the roadmap of the AES team at Tyndall National Institute towards miniaturisation and works from the current standard, the 25 mm platform [2]. A 25 mm stacked SMT IMU has been successfully developed and tested [3,4]. The goal now is to develop an even smaller version of this IMU by using advanced technology such as flexible substrates and flip-chip technique. These miniaturised IMUs are required for wearable and medical applications where size and weight are priorities. Our WIMU uses bare-die versions of off-the-shelf MEMS sensors. The Inertial Measurement Unit itself is designed to give full six degrees of freedom with 3-axis for each of the sensors-accelerometers, gyroscopes and magnetometers.

The D-Systems Project - Wireless Sensor Networks for Car-Park Management

Wireless sensor networks are collections of autonomous devices with computational, sensing and wireless communication capabilities. Research in this area has been growing in the past few years given the wide range of applications that can benefit from such a technology. This paper reports on a joint project between The Tyndall National Institute and the Computer Science Department at University College Cork, Ireland in developing a novel miniaturised modular platform for wireless sensor networks. The system architecture, hardware and software are discussed as well as details of the deployment scenario chosen for the project - a car park management system. Results and problems encountered during deployment are presented

Antenna performance measurements using wireless sensor networks

In this paper, we present the results of an experimental test methodology that was used to characterize the performance of various test antennas (commercially available and developed in-house) within a wireless sensor network node. The test method employed measures the relative performance of a number of test antennas when incorporated within a wireless sensor network node in an open-field test environment. This methodology was explored, as a means of obtaining a simple qualitative assessment of antenna performance compared to accurate, but expensive RF test hardware and anechoic chamber testing. The measured results yield some useful qualitative data in terms of antenna performance that can help in comparing and selecting a particular antenna for a wireless sensor network, as well as helping to identify cases in which detailed RF test measurements and equipment may be required for more accurate characterization

Combining inertial and visual sensing for human action recognition in tennis

In this paper, we present a framework for both the automatic extraction of the temporal location of tennis strokes within a match and the subsequent classification of these as being either a serve, forehand or backhand. We employ the use of low-cost visual sensing and low-cost inertial sensing to achieve these aims, whereby a single modality can be used or a fusion of both classification strategies can be adopted if both modalities are available within a given capture scenario. This flexibility allows the framework to be applicable to a variety of user scenarios and hardware infrastructures. Our proposed approach is quantitatively evaluated using data captured from elite tennis players. Results point to the extremely accurate performance of the proposed approach irrespective of input modality configuration

A Novel and Miniaturized 433/868MHz Multi-band Wireless Sensor Platform for Body Sensor Network Applications

Body Sensor Network (BSN) technology is seeing a rapid emergence in application areas such as health, fitness and sports monitoring. Current BSN wireless sensors typically operate on a single frequency band (e.g. utilizing the IEEE 802.15.4 standard that operates at 2.45GHz) employing a single radio transceiver for wireless communications. This allows a simple wireless architecture to be realized with low cost and power consumption. However, network congestion/failure can create potential issues in terms of reliability of data transfer, quality-of-service (QOS) and data throughput for the sensor. These issues can be especially critical in healthcare monitoring applications where data availability and integrity is crucial. The addition of more than one radio has the potential to address some of the above issues. For example, multi-radio implementations can allow access to more than one network, providing increased coverage and data processing as well as improved interoperability between networks. A small number of multi-radio wireless sensor solutions exist at present but require the use of more than one radio transceiver devices to achieve multi-band operation. This paper presents the design of a novel prototype multi-radio hardware platform that uses a single radio transceiver. The proposed design allows multi-band operation in the 433/868MHz ISM bands and this, together with its low complexity and small form factor, make it suitable for a wide range of BSN applications.

Design and Analysis of a Dual-Band Inverted-F Antenna With Orthogonal Frequency-Controlled Radiation Planes

A dual-band inverted-F antenna design operating at 433/868 MHz ISM bands is reported. The structure is planar, fed by a coplanar waveguide and easily integrated into a PCB. The device has the ability to produce radiation in two different orthogonal planes with respect to the operation frequency. This frequency-controlled radiation property offers a spherical coverage in space. A transmission line model based on the asymmetrical coplanar waveguide is used to analyze the critical parameters of the design and can be used to estimate its performance. Analytical equations are provided confirming the model and the simulations. The design procedure can be used to adjust the structure to the desired operating frequencies and to achieve the required frequency ratio (fH/fL). Measured data from a fabricated prototype show return loss greater than 10 dB at both frequency bands and are compared to simulations. Measured and simulated radiation patterns demonstrate the reconfiguration of the radiation planes with frequency that can be used for more reliable mobile communications.

Development of a wireless sensor network for collaborative agents to treat scale formation in oil pipes

A wireless network system (WSN) has been developed for a team of underwater Collaborative Autonomous Agents (CAAs) that are capable of repairing and locating scale formations in tanks and pipes within inaccessible environments. The design of the hardware is miniaturised and it consists of a stackable 25mm form-factor that includes the appropriate functionality and ISM wireless communications for the application. Sourcing of relevant sensors for the application was based on having the necessary sensing range; being miniature in size and having low power consumption. Once agent functionality was achieved, antennas were placed within the infrastructure of the pipe and CAAs to realise direct and indirect communication for the WSN.

VAMP — A Vision Based Sensor Network for Health Care Hygiene

Adequate hand-washing has been shown to be a critical activity in preventing the transmission of infections such as MRSA in health-care environments. Hand-washing guidelines published by various health-care related institutions recommend a technique incorporating six hand-washing poses that ensure all areas of the hands are thoroughly cleaned. In this paper, an embedded wireless vision system (VAMP) capable of accurately monitoring hand-washing quality is presented. The VAMP system hardware consists of a low resolution CMOS image sensor and FPGA processor which are integrated with a microcontroller and ZigBee standard wireless transceiver to create a wireless sensor network (WSN) based vision system that can be retargeted at a variety of health care applications. The device captures and processes images locally in real-time, determines if hand-washing procedures have been correctly undertaken and then passes the resulting high-level data over a low-bandwidth wireless link. The paper outlines the hardware and software mechanisms of the VAMP system and illustrates that it offers an easy to integrate sensor solution to adequately monitor and improve hand hygiene quality. Future work to develop a miniaturized, low cost system capable of being integrated into everyday products is also discussed.

A Dual-ISM-Band Antenna of Small Size Using a Spiral Structure With Parasitic Element

This letter presents a compact, single-feed, dual-band antenna covering both the 433-MHz and 2.45-GHz Industrial Scientific and Medical (ISM) bands. The antenna has small dimensions of 51 ×28 mm2. A square-spiral resonant element is printed on the top layer for the 433-MHz band. The remaining space within the spiral is used to introduce an additional parasitic monopole element on the bottom layer that is resonant at 2.45 GHz. Measured results show that the antenna has a 10-dB return-loss bandwidth of 2 MHz at 433 MHz and 132 MHz at 2.45 GHz, respectively. The antenna has omnidirectional radiation characteristics with a peak realized gain (measured) of -11.5 dBi at 433 MHz and +0.5 dBi at 2.45 GHz, respectively.

Design and measurement of a planar dual-band antenna for the Tyndall Multiradio wireless sensing platform

A planar, dual-band, Electrically Small Antenna, operating at the 433 MHz and 868 MHz ISM bands is reported, designed for the WSN Tyndall Multiradio (s-Mote) platform. It is a meandered IFA, fed by a CPW and its planar form makes it easily integrated on PCB along with the rest of the circuitry. A dual-band balun was employed to allow accurate characterization of the antenna by canceling the unbalanced behavior of the feed RF coaxial cable that causes a backwards flow of current on the shield of the coaxial cable which disturbs the measurement. Measured and simulated data are in close agreement showing Return Loss greater than 10 dB at both frequency bands. Simulated radiation patterns for the elevation and azimuthal planes with dipole-like characteristics are also included and compared with measurements followed by a discussion on the measurement setup.