Stephen Beeby

Smart textiles for smart home control and enriching future wireless sensor network data

The increasing number of objects within homes connected to the Cloud is not going to recede. Our growing acceptance of automated appliances and items connected in wireless sensor networks (WSN) is gradually making our homes smart. This occurrence is a reflection of the technological advancement of societies around the world. We predict that the future applications of WSN will incorporate smart textiles. These will appear in smart homes, as well as in commercial spaces, in automobile vehicles, in personal or business-owned clothing, and even toys. As the electronics become available to industry, smart textiles could be embedded with electronics capable of receiving and transmitting data packets. The implications are that soft furnishings or any surfaces with a textile have the potential capability of connecting to the Cloud. Considering future applications of smart textiles, whether for personal or commercial usage, we can predict data contents that would be stored in a WSN and discuss how to ensure safety and network stability.

Wearable and autonomous computing for future smart cities: Open challenges

The promise of smart cities offers the potential to change the way we live, and refers to the integration of IoT systems for people-centred applications, together with the collection and processing of data, and associated decision making. Central to the realization of this are wearable and autonomous computing systems. There are considerable challenges that exist in this space that require research across different areas of electronics and computer science; it is this multidisciplinary consideration that is novel to this paper. We consider these challenges from different perspectives, involving research in devices, infrastructure and software. Specifically, the challenges considered are related to IoT systems and networking, autonomous computing, wearable sensors and electronics, and the coordination of collectives comprising human and software agents.

Design optimization of a magnetically levitated electromagnetic vibration energy harvester for body motion

This paper presents a magnetically levitated electromagnetic vibration energy harvester based on magnet arrays. It has a nonlinear response that extends the operating bandwidth and enhances the power output of the harvesting device. The harvester is designed to be embedded in a hip prosthesis and harvest energy from low frequency movements (< 5 Hz) associated with human motion. The design optimization is performed using Comsol simulation considering the constraints on size of the harvester and low operating frequency. The output voltage across the optimal load 3.5k? generated from hip movement is 0.137 Volts during walking and 0.38 Volts during running. The power output harvested from hip movement during walking and running is 5.35 ?W and 41.36 ?W respectively

Controlled modification of resonant tunneling in metal-insulator-insulator-metal structures

We present comprehensive experimental and theoretical work on tunnel-barrier rectifiers comprising bilayer (Nb2O5/Al2O3) insulator configurations with similar (Nb/Nb) and dissimilar (Nb/Ag) metal electrodes. The electron affinity, valence band offset, and metal work function were ascertained by X-ray photoelectron spectroscopy, variable angle spectroscopic ellipsometry, and electrical measurements on fabricated reference structures. The experimental band line-up parameters were fed into a theoretical model to predict available bound states in the Nb2O5/Al2O3 quantum well and generate tunneling probability and transmittance curves under applied bias. The onset of strong resonance in the sub-V regime was found to be controlled by a work function difference of Nb/Ag electrodes in agreement with the experimental band alignment and theoretical model. A superior low-bias asymmetry of 35 at 0.1u2009V and a responsivity of 5u2009A/W at 0.25u2009V were observed for the Nb/4u2009nm Nb2O5/1u2009nm Al2O3/Ag structure, sufficient to achi...

Dataset supporting the Paper titled: Intermittently-Powered Energy Harvesting Step Counter for Fitness Tracking

This Dataset supports the Paper titled Intermittently-Powered Energy Harvesting Step Counter for Fitness Tracking, accepted for publication in IEEE Sensors Applications Symposium (SAS) 2017. n nFunded by Mexican CONACYT.

Data from: An Electromechanical Model of Ferroelectret for Energy Harvesting

Ferroelectret is a cellular polymer foam that is able to convert compressive and bending forces into electrical signals, which 10 can be used for both sensing and energy harvesting. In the past several research groups have proposed theoretical models that 11 relate the output voltage of the ferroelectret to its mechanical deformation. This is particularly useful for sensing applications 12 where the signal-to-noise ratio is important. However, for energy harvesting applications, a theoretical model needs to include 13 both the voltage across a resistive load and the duration of the electrical signal as energy is an integral of power over time. In 14 this work, we propose a theoretical model that explains the behaviour of a ferroelectret when used as an energy harvester. This 15 model can be used to predict the energy output of a ferroelectret by knowing its parameters, and therefore optimize the harvester 16 design for specific energy harvesting application.

Novel thick-foam ferroelectret with engineered voids for energy harvesting applications

This work reports a novel thick-foam ferroelectret which is designed and engineered for energy harvesting applications. We fabricated this ferroelectret foam by mixing a chemical blowing agent with a polymer solution, then used heat treatment to activate the agent and create voids in the polymer foam. The dimensions of the foam, the density and size of voids can be well controlled in the fabrication process. Therefore, this ferroelectret can be engineered into optimized structure for energy harvesting applications.

Integrated flexible solid-state supercapacitor fabricated in a single fabric layer

This paper presents the design, fabrication and characterization of a flexible solid- state electrical double layer supercapacitor fabricated in a single fabric layer. The proposed supercapacitors were based on fabric electrodes fabricated with low cost carbon materials via a spray coating technique. The single layer solid state supercapacitors achieved a specific capacitances of 40.5 F.g-1, area capacitance of 40.5 mF.cm-2.

Fabrication and characterisation of fabric based supercapacitors

This dataset is for the paper that presents details of the design, fabrication and characterisation of fabric supercapacitor devices. The proposed fabric supercapacitor devices were based on textile electrodes fabricated by a dipping technique. The textile electrodes were made with low cost porous activated carbon powder, polymer binder and polyester-cotton fabric substrates. Before supercapacitor cell assembly, some of the textile electrodes were also used to evaluate a vacuum impregnation process. The performance of the fabric supercapacitors with different percentages of carbon materials were characterised by cyclic voltammetry, galvanostatic cycling and electrochemical impedance spectroscopy. The sandwich structured supercapacitor devices achieved a high capacitance per cost of 82.9 F.

Energy harvesting for autonomous systems

-1, mass specific capacitances of 14.1 F.g-1, area specific capacitance 0.114 F.cm-2 and maintained 99% of the initial capacitance after cycling more than 15000 times.