K. Delaney

Development of field programmable modular wireless sensor network nodes for ambient systems

The goal of this work is to fabricate robust, miniature, wireless sensor modules. These provide an enabling technology platform to conduct research in creating ambient systems, through implementing wireless sensor network applications. The approach taken is to partition the wireless sensor module into a series of layers with area 25mmx25mm. This modular approach has resulted in the specification of a series of layers, including a field programmable gate array layer for digital signal processing type operations, forming the initial elements of the 25mm sensor node toolkit that can be programmed for use with different sensors depending on application. This paper highlights the development of the sensor, processing, communication and power layers, and the connection approach used to form a robust modular system. Comparisons are made with other wireless sensor nodes and application examples are given.

An architecture that treats everyday objects as communicating tangible components

The paper describes research that has been carried out in extrovert-Gadgets, a research project funded in the context of EU IST/FET proactive initiative Disappearing Computer. It presents a set of architectures for the composition of ubiquitous computing applications. The proposed architectures are part of GAS (Gadgetware Architectural Style), a generic architectural style, which can be used to describe everyday environments populated with computational artifacts. The overall innovation of the GAS approach lies in viewing the process where people configure and use complex collections of interacting eGadgets, as having much in common with the process where system builders design software systems out of components. This approach regards the everyday environment as being populated with tens even hundreds of artifacts, which people (who are always in control) associate in ad-hoc and dynamic ways.

A 3D miniaturised programmable transceiver

Purpose – To describe the development of a three dimensional programmable transceiver system of modular design for use as a development tool for a variety of wireless sensor node applications.Design/methodology/approach – As a stepping‐stone towards the development of wireless nodes, sensor networks programme was put in place to develop a 25u2009mm cube module, which was modular in construction, programmable and miniaturised in form factor. This was to facilitate the development of wireless sensor networks for a variety of different applications. The nodes are used as a platform for sensing and actuating through various parameters, for use in scalable, reconfigurable distributed autonomous sensing networks in a number of research projects currently underway in the Tyndall Institute, as well as other institutes and in a variety of research programs in the area of wireless sensor networks.Findings – The modular construction enables the heterogeneous implementation of a variety of technologies required in the ar...

FPGA implementation of spiking neural networks - an initial step towards building tangible collaborative autonomous agents

This work contains the results of an initial study into the FPGA implementation of a spiking neural network. This work was undertaken as a task in a project that aims to design and develop a new kind of tangible collaborative autonomous agent. The project intends to exploit/investigate methods for engineering emergent collective behaviour in large societies of actual miniature agents that can learn and evolve. Such multi-agent systems could be used to detect and collectively repair faults in a variety of applications where it is difficult for humans to gain access, such as fluidic environments found in critical components of material/industrial systems. The initial achievement of implementation of a spiking neural network on a FPGA hardware platform and results of a robotic wall following task are discussed by comparison with software driven robots and simulations.

Characterization and performance prediction for integral capacitors in low temperature co-fired ceramic technology

This paper addresses the electrical characterization of integral capacitors in low temperature co-fired ceramic (LTCC). The technology also includes integrated resistors and inductors. It first discusses the geometry and fabrication of the capacitor technology, which uses a novel insert method in LTCC substrates. The structures of 300 special test vehicles made to analyze the technique are described. The samples include components in the range 140 pF to 9.6 nF, and single-layer and two-layer integral formats; structure fabrication capability is currently 7.8 nF/cm/sup 2/. Test vehicle variants, fabricated to analyze the effects of processing parameters such as lamination pressure, are discussed. Measurement systems, which were built to electrically characterize the integral capacitors, are described. The results of the analyzes are summarized with regard to the individual and combined impact of applied frequency, temperature, and DC voltage parameters. The effects of lamination pressure, capacitor size, and the number of dielectric layers are also evaluated. The paper then discusses the development of predictive functions for the induced electrical performance variations in the capacitors, functions that are necessary to enable designers to properly develop circuits for applications in various operating environments. The results of an analysis of the geometry of the capacitors are presented, and are employed by electrical models made using analytical methods, boundary element methods (BEM), and finite element methods (FEM). The models are a requirement for process engineers in optimizing the capacitor fabrication techniques, and for design engineers as means of defining the correct component geometries for their circuits.

The DSYS25 sensor platform

In this demonstration, a new sensor platform named DSYS25 is presented. The platform has a unique hardware design and runs a customized version of the TinyOS operating system. Transceiver hardware and packaging distinguish the D-Systems platform from other available designs.

Development of distributed sensing systems of autonomous micro-modules

This paper focuses on the development of miniaturised modular wireless sensor networks that can be used to realise distributed autnnomous sensors for future ad-hoc networks. Such modular, mobile networks are key enablig technologies in the field of ubiquitous computing and wearable electronics. The Ambient Systems team in the NMRC has adopted a phased approach to developing ultra-miniature sensor nodes with a goal of implementation of a 1mm3 (or less) autonomous sensor module. This paper will detail the progress through phases 1 and 2. The phase 1 modules are 25mm cubes, fabricated as a 3-D stackable modular PCB, which can he mounted on mobile devices or wom on the body; they can measure acceleration, rotation, shock. elevation etc. and have an ultra low-power RF channel-shared link to a base station. There are numerous possible applications in the fields of sports, exercise, entertainment and health. Extra panels, including sensory, memory or computation can be designed and added as needed. This make the phase 1 module a powerful test platform for developing future automous sensor systems. The phase 2 modules have a much reduced form factor, approximately a lcm cube; as well as the modularity developed in phase 1, the phase 2 form contains actuators and a PLD platform. lntrnductinn Major research efforts are currently targeting the disappearance of the computer into the fabric of our environment. In the future, the spaces we live in will be populated by many thousands of objects (often described as artefacts) with the ability to sense and actuate in their environment, to perform localised computation, and to communicate, even collaborate with each other. Artefacts are playing a large role in research towards intelligent systems and ubiquitous computing[l]. There are two prime drivers: the smaller these objects are the more effective they will be in providing opportunities for integrating the physical and digital worlds, and the greater the number of objects within these systems/networks the more valuable the networks are (Metcalfes Law). The main properties required to maximise the capabilities of such networks are that it should have high granularity (i.e. high resolution), reconfigurability modularisation and mobility. The system level implementation will be realised through concurrent hardware and software co-design and engineering; innovation in software should be matched by invention in hardware. It is notable in this regard that many issues are comparably

Development and characterisation of ultra thin autonomous modules for ambient system applications using 3D packaging techniques

The work presented in this paper represents two strands of the work of the ambient system team at NMRC to produce ultraminiature sensor modules (K. Delaney et al, Proc. 40th IMAPS Nordic Conf., pp. 13-21, 2003). These modules with an ultimate target size of <1 mm/sup 3/ are needed for the implementation of future ad-hoc networks for ambient systems. Ambient systems stem from convergence of three key technologies: ubiquitous computing, ubiquitous communication and intelligent user friendly interfaces. On convergence, humans will be surrounded by intelligent interfaces, supported by computing and networking technology which is everywhere, embedded in everyday objects such as furniture, clothes, vehicles, and smart materials. The work done for the realisation of the 1 mm/sup 3/ autonomous sensor module is following a technology roadmap developed by NMRC. The work is carried out in different phases: in the first phase a 25 mm cube fabricated as 3D stackable modular PCB is being reported (J. Barton et al, UbiComp 2002, and ICEWES 2002). The current module is a 1 cm cube, combining a microcontroller, PLD, accelerometer, light dependant resistors and coloured LEDs with the aim of creating modular wireless computational unit (J. Barton et al, Proc. 53rd Electron. Comp. and Tech. Conf., 2003). This paper details the assembly, characterisation and reliability issues of this module while work done to realise a very thin multi layer flexible substrate for a 5 mm cube is presented.

Characterisation of the electrical performance of buried capacitors and resistors in low temperature co-fired (LTCC) ceramic

This paper describes the electrical characterisation of a novel integrated passive component technology developed using low temperature co-fired ceramic (LTCC) techniques which provides high quality buried capacitors, up to 7.8 nF/cm/sup 2/, and buried resistor materials in the range 100 /spl Omega//sq. to 20 k/spl Omega//sq. The characterisation was undertaken to analyse the components performance under the individual and combined effects of applied frequency (100 Hz-13 MHz), temperature (-60C to +160C), and DC voltage (-35 volts to +35 volts). The results seen when these applied parameters were varied with regard to one another show complex interactive behaviour which was a function of the materials used. The scope of the work (/spl sim/6500 buried LTCC capacitors and resistors) facilitated analysis of such effects on a statistical level and over a number of material batches. A series of electrical models were completed and two sets of predictive functions were derived for the capacitors and the resistors. The models employed data taken from measurements of cross-sections of a number of different component geometries, and the accuracy of the final models facilitated prediction of process related defects present where manufacturing parameters are not optimised. The predictive functions allow designers to confidently anticipate the electrical performance of the components over the entire working temperature range of the target application.

Innovative packaging techniques for wearable applications using flexible silicon fibres

A novel technology (A. Mathewson et al., Irish Preliminary Patent P129447) that has the potential to make current wearable electronics recede even further into the background of everyday life has been developed in the form of electronically functional fibres (EFF). This is achieved by building a device in silicon on insulator (SOI) (James B. Kou and Ker-Wei Su, CMOS VLSI Engineering Silicon on Insulator (SOI), Kluwer Academic Publishers, Boston, pp. 15-59, 1998) material and under-cutting the sacrificial SiO/sub 2/ layer by means of an isotropic etch process to leave a freestanding functional fibre. A demonstration of functionality based on this technology was produced in the form of a PN diode on a fibre (T. Healy et al., IEEE 53rd Electron. Comp. and Tech. Conf., pp. 1119-1122, 2003). One of the key initial considerations involved with this technology is the interconnection of such flexible structures. One approach to resolving this issue is to use a flexible printed circuit board (PCB) and a conductive adhesive paste to interconnect the individual fibres. A prototype demonstration of this technology in the form of a flexible light emitting diode (LED) circuit, using the EFF as the resistor of the circuit, is presented in this publication.