Respiratory rate (RR) is an important physiological parameter whose abnormality has been regarded as an important indicator of serious illness. In order to make RR monitoring simple to perform, reliable and accurate, many different methods have been proposed for such automatic monitoring. According to the theory of respiratory rate extraction, methods are categorized into three modalities: extracting RR from other physiological signals, RR measurement based on respiratory movements, and RR measurement based on airflow. The merits and limitations of each method are highlighted and discussed. In addition, current works are summarized to suggest key directions for the development of future RR monitoring methodologies.

https://iopscience.iop.org/article/10.1088/1361-6579/ab299e/pdf

Recent development of respiratory rate measurement technologies

Droplet-based microfluidics is a colloidal and interfacial system that has rapidly progressed in the past decade because of the advantages of low fabrication costs, small sample volumes, reduced analysis durations, high-throughput analysis with exceptional sensitivity, enhanced operational flexibility, and facile automation. This technology has emerged as a new tool for many recently used applications in molecular detection, imaging, drug delivery, diagnostics, cell biology and other fields. Herein, we review recent applications of droplet microfluidics proposed since 2013.

Recent Advances in Applications of Droplet Microfluidics

Human Physiology An Integrated Approach

Microfluidic synthesis control technology and its application in drug delivery, bioimaging, biosensing, environmental analysis and cell analysis

An intelligent digital microfluidic processor for biomedical detection is presented. This potential architecture solves lots of traditional development bottlenecks to implement the easy-to-control, easy-to-monitor, system automation and high accuracy for bioassay detection purposes. The proposed processor integrates the functions of microfluidic actuation, droplet location readback and high sensitivity measurement window to demonstrate a novel prototype for personalized medicine. Furthermore, the droplet location map and reaction behaviors are visible on a 2-dimentional (2D) graphical user-interface due to the micro electrode dot array (MEDA) architecture and capacitive sensing technology, and hence system automation is achievable. Fabricated in standard 0.35 μm CMOS process, this work integrates 900 microelectrodes with measurement window in 3.2 mm2, where the high sensitivity capacitive readout circuit occupies only 0.048 mm2. Measurement results show that microdroplet actuation and 2D location map are activated under 1KHz. In addition, the function of digital signal extraction, processing, as well as statistical analysis can be operated under 1 MHz respectively.

An Intelligent Digital Microfluidic Processor for Biomedical Detection

A digital sensing apparatus includes a sensing unit capable of providing a sensing response associated with an environmental parameter, and a digital readout module including a reading unit for generating a pulse signal having a pulse width as sociated with the sensing response, and a converting unit. The converting unit includes a clock signal generator for generating a variable-frequency clock signal, and a counter operable to count a width value of the pulse width of the pulse signal using the clock signal, so as to generate a digital sensing code. The frequency of the clock signal from the clock signal generator is adjustable to adjust resolution of the width value of the pulse width of the pulse signal.

https://ir.nctu.edu.tw:443/bitstream/11536/104372/1/08736251.pdf

Digital sensing apparatus and digital readout module thereof

The invention provides a digital readout module and a digital sensing apparatus. The digital sensing apparatus includes a sensing unit capable of providing a sensing response associated with an environmental parameter, and a digital readout module including a reading unit for generating a pulse signal having a pulse width as sociated with the sensing response, and a converting unit. The converting unit includes a clock signal generator for generating a variable-frequency clock signal, and a counter operable to count a width value of the pulse width of the pulse signal using the clock signal, so as to generate a digital sensing code. The frequency of the clock signal from the clock signal generator is adjustable to adjust resolution of the width value of the pulse width of the pulse signal.

Digital readout module and digital sensing apparatus

In this paper, an energy-efficient monitor, including three capacitive and two resistive readout circuits with hardware-sharing architecture, is presented for female ovulation. The proposed design is featuring two calibration modules: one decreases the initial offset by capacitor array, and the other reduces P-V-T variations by taking proportion between sensing and ruler results. After implemented in UMC 0.18μm CMOS-MEMS technology, the post-layout simulation results show that our circuit consumes 30μW and 49μW in 0.8ms conversion time under 1.8V supplied voltage for 1-axis and 3-axis. The capacitive resolution is around 0.1fF and the sensing range of die-temperature is 0∼100°C with 0.05°C resolution.

A multi-axis readout circuit using in female ovulation monitoring platform

As Internet of Things (IoT) and wearable devices become the next wave of emerging markets, it is very necessary to provide a set of sensors related to target applications so that decision-making becomes more reliable from collected data. However multi-sensor approach results in higher data rate and larger power consumption, which may not be accepted by application requirements, e.g. mobile health-care. In this paper, a sensor-fusion approach will be introduced to provide an energy-efficient and data-reliable solution. By exploiting event-driven architecture, energy efficiency can be enhanced; on the other hand, analysis accuracy can be further improved with the support of multi-data sets. As a result, both power consumption and data bandwidth can be minimized with better accuracy to meet those specifications in battery-operated devices. A test vehicle related to mobile health-care applications will also be introduced to demonstrate the feasibility of our proposal.

A Sensor-Fusion Solution for Mobile Health-Care Applications

Smart sensors are currently demanded in various kinds of applications to pave a way for better life. To reach this goal, it is necessary to provide energy-efficient solutions with analysis capability. Though state-of-the-art SoC's can meet μW-level processing requirements, front-end sensors remain a bottleneck to be solved. In this paper, a few sensors based on event-driven techniques to improve energy-efficiency and accuracy will be first addressed. Then an ECG-SoC for mobile health-care applications will be described and illustrated.

Kelvin Yi-Tse Lai

Papers

Digital sensing apparatus and digital readout module thereof

Digital readout module and digital sensing apparatus

A multi-axis readout circuit using in female ovulation monitoring platform

A Sensor-Fusion Solution for Mobile Health-Care Applications

Event-driven read-out circuits for energy-efficient sensor-SoC's