Miniaturised infrared spectrophotometer for low power consumption multi-gas sensing

Concept, design and practical implementation of a miniaturized spectrophotometer, utilized as a mid-infrared-based multi gas sensor is described. The sensor covers an infrared absorption wavelength range of 2.9 to 4.8 um, providing detection capabilities for carbon dioxide, carbon monoxide, nitrous oxide, sulphur dioxide, ammonia and methane. A lead selenide photo-detector array and customized MEMS-based micro-hotplate are used as the detector and broadband infrared source, respectively. The spectrophotometer optics are based on an injection moulded Schwarzschild configuration incorporating optical pass band filters for the spectral discrimination. This work explores the effects of using both fixed-line pass band and linear variable optical filters. We report the effectiveness of this low-power-consumption miniaturized spectrophotometer as a stand-alone single and multi-gas sensor, usage of a distinct reference channel during gas measurements, development of ideal optical filters and spectral control of the source and detector. Results also demonstrate the use of short-time pulsed inputs as an effective and efficient way of operating the sensor in a low-power-consumption mode. We describe performance of the spectrometer as a multi-gas sensor, optimizing individual component performances, power consumption, temperature sensitivity and gas properties using modelling and customized experimental procedures

A highly miniaturized wireless inertial sensor using a novel 3D flexible circuit

Purpose - The purpose of this paper is to develop a highly miniaturized wireless inertial sensor system based on a novel 3D packaging technique using a flexible printed circuit (FPC). The device is very suitable for wearable applications in which small size and lightweight are required such as body area network, medical, sports and entertainment applications.Design/methodology/approach - Modern wireless inertial measurement units are typically implemented on a rigid 2D printed circuit board (PCB). The design concept presented here is based around the use of a novel planar, six-faceted, crucifix or cross-shaped FPC instead of a rigid PCB. A number of specific functional blocks (such as microelectromechanical systems gyroscope and accelerometer sensors, microcontroller (MCU), radio transceiver, antenna, etc.) are first assigned to each of the six faces which are each 1 cm2 in area. The FPC cross is then developed into a 1 cm3, 3D configuration by folding the cross at each of five bend planes. The result is a low-volume and lightweight, 1 cm3 wireless inertial sensor that can sense and send motion sensed data wirelessly to a base station. The wireless sensor device has been designed for low power operation both at the hardware and software levels. At the base station side, a radio receiver is connected to another MCU unit, which sends received data to a personal computer (PC) and graphical user interface. The industrial, scientific and medical band (2.45 GHz) is used to achieve half duplex communication between the two sides.Findings - A complete wireless sensor system has been realized in a 3D cube form factor using an FPC. The packaging technique employed during the work is shown to be efficient in fabricating the final cubic system and resulted in a significant saving in the final size and weight of the system. A number of design issues are identified regarding the use of FPC for implementing the 3D structure and the chosen solutions are shown to be successful in dealing with these issues.Research limitations/implications - Currently, a limitation of the system is the need for an external battery to power the sensor system. A second phase of development would be required to investigate the possibility of the integration of a battery and charging system within the cube structure. In addition, the use of flexible substrate imposes a number of restrictions in terms of the ease of manufacturability of the final system due to the requirement of the required folding step.Practical implications - The small size and weight of the developed system is found to be extremely useful in different deployments. It would be useful to further explore the system performance in different application scenarios such as wearable motion tracking applications. In terms of manufacturability, component placement needs to be carefully considered, ensuring that there is sufficient distance between the components, bend planes and board edges and this leads to a slightly reduced usable area on the printed circuit.Originality/value - This paper provides a novel and useful method for realizing a wireless inertial sensor system in a 3D package. The value of the chosen approach is that a significant reduction in the required system volume is achieved. In particular, a 78.5 per cent saving in volume is obtained in decreasing the module size from a 25 to a 15 mm3 size

Fabrication and evaluation of a micro(bio)sensor array chip for multiple parallel measurements of important cell biomarkers

© 2014 by the authors; licensee MDPI, Basel, Switzerland. This report describes the design and development of an integrated electrochemical cell culture monitoring system, based on enzyme-biosensors and chemical sensors, for monitoring indicators of mammalian cell metabolic status. MEMS technology was used to fabricate a microwell-format silicon platform including a thermometer, onto which chemical sensors (pH, O2) and screen-printed biosensors (glucose, lactate), were grafted/deposited. Microwells were formed over the fabricated sensors to give 5-well sensor strips which were interfaced with a multipotentiostat via a bespoke connector box interface. The operation of each sensor/biosensor type was examined individually, and examples of operating devices in five microwells in parallel, in either potentiometric (pH sensing) or amperometric (glucose biosensing) mode are shown. The performance characteristics of the sensors/biosensors indicate that the system could readily be applied to cell culture/toxicity studies

Micro-manufacturing research : drivers and latest developments (Keynote Paper)

Increased demands on micro-products and miniaturised systems/devices may have been a main driver to the rapid growth of the interest in research in micro- and nano-manufacturing. It seems, however, not to be the only reason why so much funding has been made available for researchers to be able to conduct research in this emerging field. A review was conducted recently with a view to gaining a clearer view of demands on the applications and on trends in developments in micro-manufacturing, by looking at the market, research topics, projects, interactions with industry, outcomes and applications. It was found that there have been significant changes/advances in micro-manufacturing research, compared to what had been undertaken and achieved in 5 ~ 10 years ago, being reflected especially by: (i). micro-manufacturing research bridging “nano-manufacturing” and “macro-manufacturing” and hence, bringing nano-technology into real-life and affordable products; (ii). addressing multi-length scale manufacturing problems and hence, linking it to macro-sized product manufacturing, which adds its relevance to general manufacturing and wide-sector applications; (iii). micro-manufacturing research being shifted from “process focus” to “market/product” driven research and technological development addressing production capability, product quality, pilot production line demonstration and delivery; and (iv). micro-manufacturing research playing roles in helping to transform traditional industry and products. These new developments may justify past and current significant investment in research and technological development in micro- and nano-manufacturing, and suggest more significant impacts to come in near future