FlexStylus, a flexible stylus, detects deformation of the barrel as a vector with both a rotational and an absolute value, providing two degrees of freedom with the goal of improving the expressivity of digital art using a stylus device. We outline the construction of the prototype and the principles behind the sensing method, which uses a cluster of four fibreoptic based deformation sensors. We propose interaction techniques using the FlexStylus to improve menu navigation and tool selection. Finally, we describe a study comparing users' ability to match a changing target value using a commercial pressure stylus and the FlexStylus' absolute deformation. When using the FlexStylus, users had a significantly higher accuracy overall. This suggests that deformation may be a useful input method for future work considering stylus augmentation.

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Structurally integrated sensors which are capable of continuous structural health monitoring represent an attractive option in view of their potential for providing real-time assessment/ warning of structural damage. In recent years, optical fiber systems have attracted a considerable amount of attention and have been shown to be a very attractive option for health monitoring in advanced composite materials. These sensors have either been embedded or surfacebonded to the host material thereby allowing continuous assessment of the health of the structure. Structural health assessment takes the form of damage detection and/or monitoring of specific health indicators. In the former approach, the optical fiber systems are generally optimized to increase their sensitivity to the presence of damage in the composite structure, while the latter approach relies on the examination of characteristic changes in the monitored parameter to infer a loss in structural integrity. To this end, many investigators have demonstrated the potential of optical fiber sensors, most particularly intensity-based optical fiber systems and fiber Bragg grating sensors for structural health monitoring of advanced composite materials. The initial part of this paper provides an up-to-date review of the applications of optical fiber sensors in composite materials, focussing particularly on the use of intensitybased optical fiber systems and fiber Bragg grating sensors for damage detection. These optical fiber systems have been shown to be capable of detecting impact damage, transverse cracking, and delamination, and have the ability to monitor strain in structures. The introduction of optical fiber sensors into a composite material can inadvertently produce a geometrical discontinuity in the vicinity of the sensor. Numerous experimental investigations have also been performed to assess the possible reduction in the properties of the host structure. A review of the findings of these investigations reported in the literature is also given. This review article cites 161 references.

While a number of literature reviews have been published in recent times on the applications of optical fibre sensors in smart structures research, these have mainly focused on the use of conventional glass-based fibres. The availability of inexpensive, rugged, and large-core plastic-based optical fibres has resulted in growing interest amongst researchers in their use as low-cost sensors in a variety of areas including chemical sensing, biomedicine, and the measurement of a range of physical parameters. The sensing principles used in plastic optical fibres are often similar to those developed in glass-based fibres, but the advantages associated with plastic fibres render them attractive as an alternative to conventional glass fibres, and their ability to detect and measure physical parameters such as strain, stress, load, temperature, displacement, and pressure makes them suitable for structural health monitoring (SHM) applications. Increasingly their applications as sensors in the field of structural engineering are being studied and reported in literature. This article will provide a concise review of the applications of plastic optical fibre sensors for monitoring the integrity of engineering structures in the context of SHM.

Plastic optical fibres have been employed to detect initial cracks, monitor post-crack vertical deflection and detect failure cracks in concrete beams subjected to flexural loading conditions. The intensity-based sensor system relies on monitoring the modulation of light intensity within the optical fibre as the sensor is loaded. The sensor design offers good signal stability and sensitivity to the monitored parameter and represents a cost-effective alternative to other more sophisticated health-monitoring systems currently used in civil engineering structures.Here, a series of three-and four-point bend tests was conducted on a range of structures. Initially, the optical fibres were attached to scale-model concrete samples (without reinforcement) to evaluate their ability to monitor beam deflection and detect cracks. Similar tests were subsequently conducted on life-size concrete beams containing reinforcing steel bars. The location and subsequent trajectory of cracks during the loading regime were marked and then compared to the sensor signal to assess the sensor's ability to monitor crack development.The results demonstrate the possibility of using optical fibres to detect hairline cracks and ultimate failure crack in civil engineering structures and highlight their ability to monitor crack propagation up to ultimate failure. In addition to detecting the initiation of a crack, good agreement between the sensor output and crack progression during loading was also obtained in these concrete beams.