Design of a compact, fully-autonomous 433 MHz tunable antenna for wearable wireless sensor applications

The authors present the design of a tunable 433 MHz antenna that is tailored for wearable wireless sensor applications. This study first presents a detailed analysis of the measured impedance characteristics of a chosen antenna under test (AUT) in varying proximity to a human test subject. Instead of limiting the analysis to the head and hand only, this analysis measures the AUT impedance at varying distances from 11 different body positions. A novel antenna equivalent circuit model is then developed that enables both the free-space and total on-body AUT impedance variation to be rapidly computed using a circuit simulator instead of the requirement for computationally intensive finite-element methods for example. The design and characterisation of a tunable matching network that enables AUT impedance matching for 11 different positions on the human body is then outlined. Finally, a fully-autonomous 433 MHz tunable antenna is demonstrated. The antenna occupies a small printed circuit board area of 51 × 28 mm and is printed on standard FR-4 material with the tuner completely integrated into the antenna itself. Prototype measurements show an improvement of 3.9 dB in power delivery to the antenna for a load voltage standing wave ratio of 17:1, with a maximum matching loss of 0.84 dB and S11 (−10 dB) ≥ 18 MHz for all load conditions

A novel first responders location tracking system: Architecture and functional requirements

The aim of the SAFESENS (Sensor Technologies for Enhanced Safety and Security of Buildings and its Occupants) project is to obtain earlier and more reliable fire detection, along with accurate occupancy detection and first responders\u27 health condition and indoor location monitoring. In this paper, an analysis of the requirements requested by the tracking system is shown, together with an overview of the exploitable technologies and the current state-of-the-art. A novel system architecture, mainly based on UWB, inertial sensors, barometer and Bluetooth Low-Energy (BLE), is proposed also showing some preliminary results regarding the chosen technologies. The final system will be shown in several real-case applications on successful completion of the project

Improved NLOS Error Mitigation Based on LTS Algorithm

A new improved Least Trimmed Squares (LTS) based algorithm for Non-line-of sight (NLOS) error mitigation is proposed for indoor localisation systems. The conventional LTS algorithm has hard threshold to decide the final set of base stations (BSs) to be used in position calculations. When the number of Line of Sight (LOS) base stations is more than the number of NLOS BSs the conventional LTS algorithm does not include some of them in position estimation due to principle of LTS algorithm or under heavy NLOS environments it cannot separate least biased BSs to use. To improve the performance of the conventional LTS algorithm in dynamic environments we have proposed a method that selects BSs for position calculation based on ordered residuals without discarding half of the BSs. By choosing a set of BSs which have least residual errors among all combinations as a final set for position calculation, we were able to decrease the localisation error of the system in dynamic environments. We demonstrate the robustness of the new improved method based on computer simulations under realistic channel environments

On the use of Wireless Sensor Networks in Preventative Maintenance for Industry 4.0

The goal of this paper is to present a literature study on the use of Wireless Sensor Networks (WSNs) in Preventative Maintenance applications for Industry 4.0. Requirements for industrial applications are discussed along with a comparative of the characteristics of the existing and emerging WSN technology enablers. The design considerations inherent to WSNs becoming a tool to drive maintenance efficiencies are discussed in the context of implementations in the research literature and commercial solutions available on the market

A 3D hand motion capture device with haptic feedback for virtual reality applications

In this paper, the challenges associated with the design of new generation hand motion capture devices for Virtual Reality (VR) applications are described. The need for developing a hand motion capture device with tactile feedback that integrates all the sensors and actuators associated with VR, while meeting the latency requirements is introduced. A detailed description of functional and non-functional specifications is also given. Finally, a comparison study with commercially available technology is provided highlighting that the proposed device compares favorably not only in terms of functional parameters, such as connectivity, integration of sensors and actuators, and latency, but also in terms of non-functional parameters, e.g., no need to wash, ambidextrous features and modularity

Performance analysis of a novel flexible NFC Tag for IoT applications

This work reports on the simulation and analysis of passive near field communication (NFC) technology that investigates the impact of the interconnect conductivity on its performance characteristics. Recently, flexible wearable devices and sensors are in great demand in healthcare applications 1. Flexible NFC devices can be developed by employing novel interconnect materials such as polymer-metal composites [2]. However, these materials have a comparatively lower conductivity than conventional metals such as copper and silver [3]. The effect of interconnect conductivity on the performance of an NFC tag antenna through simulation and experiments are presented

A wearable hybrid IEEE 802.15.4-2011 ultra-wideband/inertial sensor platform for ambulatory tracking

Ultra-Wideband (UWB) transceivers and low-cost micro electro mechanical systems (MEMS) based inertial sensors are proving a promising hybrid combination for location specific wearable applications. While several hybrid systems have been proposed to date, current approaches consider inertial sensors and UWB as ad-hoc components working in isolation. As a result issues surrounding extensive infrastructure requirements, synchronization, and limitations associated with the mutual sharing of inertial data have arisen. In an attempt to address such limitations, this paper presents a fully-coupled architecture whereby standardised IEEE 802.15.4-2011 UWB is employed for both ranging and as a mechanism for exchanging inertial data between the nodes of a network. A proof-of-concept system is implemented and tested for a single ambulatory use case scenario. Basic fusion algorithms are employed and the preliminary results show the benefits of a fully-coupled approach when compared with traditional standalone inertial navigation