Microfluidic system with a wireless paired emitter detector diode device as optical sensor for water quality monitoring

Increased demand for improved water management is driving need for water quality monitoring systems with greatly improved price/performance characteristics. This work presents the first use of wireless paired emitter detector diode device (PEDD) as an optical sensor for colorimetric analysis of water quality in a Lab-on-a-disc device format. The instrument detector involves using two light emitting diodes (LEDs), which act as both a light source and photo detector (Fig. 1a.). In comparison to the more commonly used method of coupling a LED to a photodiode, this technique achieves excellent sensitivity and signal-to-noise ratio, with very low cost fabrication and electronics. Furthermore, its low power consumption, increasing spectral range coverage, excellent intensity and efficiency, small size, ease of fabrication and simplicity of the PEDD make it a perfect optical detector for colorimetric assays [1]. In addition, the device is ideally suited for integration with microfluidic platforms based on the centrifugal Lab-on-a-Disc concept, in which detector difficulties can arise due to the high rotation speed typically used in this approach [2]. In this work the calibration of the system using bromocresol purple (BCP) is demonstrated. Concentration ranges were examined in parallel using UV-Vis spectroscopy as control, and the PEDD system. Similar limits of detection (ca. 2.5x10-4 M, Fig.1b.) were obtained in both cases. However, the PEDD system presented a linear trend over a wider range of concentrations. The experiments demonstrate the potential for the wireless PEDD to be a versatile and cheap alternative optical detector system for water quality monitoring in microfluidic applications

Web-based sensor streaming wearable for respiratory monitoring applications.

This paper presents a system for remote monitoring of respiration of individuals that can detect respiration rate, mode of breathing and identify coughing events. It comprises a series of polymer fabric-sensors incorporated into a sports vest, a wearable data acquisition platform and a novel rich internet application (RIA) which together enable remote real-time monitoring of untethered wearable systems for respiratory rehabilitation. This system will, for the first time, allow therapists to monitor and guide the respiratory efforts of patients in real-time through a web browser. Changes in abdomen expansion and contraction associated with respiration are detected by the fabric sensors and transmitted wirelessly via a Bluetooth-based solution to a standard computer. The respiratory signals are visualized locally through the RIA and subsequently published to a sensor streaming cloud-based server. A web-based signal streaming protocol makes the signals available as real-time streams to authorized subscribers over standard browsers. We demonstrate real-time streaming of a six-sensor shirt rendered remotely at 40 samples/s per sensor with perceptually acceptable latency (<0.5s) over realistic network conditions