Systems for Printed Flexible Sensors: Design and implementation

Description

Flexible devices are gradually emerging as an alternative viable low-cost user-friendly technology for wearable health care services in different fields. Some of the attractive features of flexible devices are the integration of multiple sensing units with electronic circuits for any planar and non-planar mounting surfaces. With the advancement of flexible technologies, now the devices can be fabricated with superior response characteristics comparable to the conventional silicon IC technology. The purpose of the present book is to provide the readers with a single platform to develop a system using flexible sensors integrating with interfacing/signal conditioning, data conversion and communication circuits. Key Features: First book with focus on interfacing flexible sensorsComprehensive topics on different types of flexible sensors for sensing applicationsSelection of materials, design of sensor structures and fabrication of the flexible sensorsInterfacing circuits for a range of flexible sensors including capacitive and imperfect capacitive sensors, resistive sensors and othersExtensive incorporation of case studies PRELIMS.pdf Preface Acknowledgment Editors’ biographies Tarikul Islam Subhas Chandra Mukhopadhyay Boby George List of contributors CH001.pdf Chapter 1 A review on flexible sensors for soft robotics 1.1 Introduction 1.2 Important characteristics required for soft robotics sensors 1.3 Sensing techniques employed to develop soft robotic sensors 1.3.1 Magnetic sensors 1.3.2 Inductive sensors 1.3.3 Capacitive sensors 1.3.4 Strain gauge/resistance-based sensors 1.3.5 Eddy current sensors 1.3.6 Optical sensors 1.4 Interfacing circuits and associated measurement systems 1.5 Comparison of different sensing techniques 1.6 Challenges and future directions References CH002.pdf Chapter 2 Recent advances in laser-induced graphene (LIG)-based flexible electronic devices 2.1 Introduction 2.1.1 Characterization techniques 2.2 LIG fabrication 2.2.1 LIG chemical modification 2.3 LIG in electronic devices 2.3.1 LIG-based miniaturized fuel cells 2.3.2 LIG-based miniaturized energy-storage devices 2.3.3 LIG heaters 2.3.4 LIG sensors 2.4 LIG in wearable and smart devices 2.5 Conclusion and future outlook References CH003.pdf Chapter 3 Printable flexible sensors for hydration monitoring and moisture measurement in concrete structures 3.1 Introduction 3.2 Hydration and its monitoring using flexible sensors 3.2.1 Ultrasonic technique 3.2.2 Hydration monitoring by temperature measurement 3.3 Hydration of concrete using transformer principle 3.4 Determination of the response parameters of concrete 3.4.1 Fringing field flexible capacitive sensors for hydration monitoring 3.5 Flexible sensors for moisture measurement in concrete 3.5.1 Fringing field capacitive sensors for concrete moisture measurement 3.5.2 Theory of the proposed method 3.5.3 Modeling of the sensor 3.5.4 Experimental moisture measurement results in cement slab 3.6 Conclusion References CH004.pdf Chapter 4 Resistive sensor interface 4.1 Introduction 4.2 Auto-balancing interface circuits 4.2.1 Circuit architecture and operation 4.2.2 Circuit analysis 4.2.3 Prototype design and experimental results 4.2.4 Experimental result with sensor 4.2.5 Discussion 4.3 Auto-balancing interface for resistive sensor array 4.3.1 Circuit architecture and operation 4.3.2 Circuit analysis 4.3.3 Prototype design and experimental results 4.3.4 Experimental measurement with a silicon nanowire array 4.3.5 Discussion 4.3.6 Summary 4.4 Conclusion and industrial aspects 4.5 Future of sensing technology References CH005.pdf Chapter 5 Interfacing circuit for capacitive sensors 5.1 Introduction 5.2 Capacitive sensors: basic principles 5.2.1 Variable gap type 5.2.2 Variable area type 5.2.3 Variable dielectric type 5.2.4 Differential configuration 5.3 Sensor interfacing techniques 5.3.1 Capacitance-to-frequency converter 5.3.2 Continuous-time interface 5.3.3 Discrete-time interface 5.3.4 Chopper stabilization 5.3.5 Auto-zeroing (AZ) technique 5.3.6 Correlated double-sampling 5.4 Capacitance-to-digital converters 5.4.1 Dual-slope CDC 5.4.2 Succesive approximation register type 5.4.3 Sigma delta modulator-type 5.5 Sensor mismatch cancellation 5.5.1 Capacitance array 5.5.2 Voltage-mode charge balance method 5.5.3 Auto-cancellation of sensor mismatch 5.6 Case study: integrated capacitance measurement system 5.6.1 Circuit components 5.7 Conclusion References CH006.pdf Chapter 6 Interface electronics and conditioning circuits for triboelectric flexible sensors 6.1 Introduction 6.2 Characteristics of triboelectric sensors 6.3 Block structure of interface electronics 6.3.1 Preamplifier 6.3.2 Filtering 6.4 Design examples of analog front-end 6.5 Case study: circuitry for a grating-patterned triboelectric human–machine interface 6.5.1 Design and working mechanism of a triboelectric sensor 6.5.2 Signal-conditioning circuit 6.5.3 Design of the printed circuit board 6.5.4 Experimental results 6.6 Summary References CH007.pdf Chapter 7 Flexible interfacing circuits for wearable sensors and wireless communication 7.1 Introduction 7.2 Wearable sensors and interfacing circuits 7.2.1 Non-self-powered sensors and interfacing circuits 7.2.2 Chemical sensors and interfacing circuits 7.2.3 Self-powered systems and interfacing circuits 7.3 Interfacing circuits for wireless communication 7.4 Conclusion and future perspective References CH008.pdf Chapter 8 Compact and efficient wireless power and information transfer systems for IoT sensors and implants 8.1 Introduction 8.2 Examples from the literature 8.3 Figure-8 inductor 8.3.1 Structure of a figure-8 inductor 8.3.2 Self-inductance of the figure-8 inductor 8.3.3 Losses of the figure-8 inductor 8.3.4 Mutual inductance between two figure-8 inductors 8.3.5 Cross-coupling with DGS inductor 8.4 System design and discussions 8.4.1 System layout 8.4.2 Fabrication 8.4.3 Measurement category 1: S-parameters 8.4.4 Measurement category 2: misalignment 8.4.5 Measurement category 3: simultaneous wireless power and information transfer 8.5 Conclusion References CH009.pdf Chapter 9 Analysis and design considerations of relaxation-oscillator-based flexible sensor circuits 9.1 Introduction 9.2 Relaxation-oscillator-based circuits 9.2.1 Conventional relaxation-oscillator-based interface 9.2.2 Analysis for time period T 9.2.3 Conventional relaxation-oscillator-based interface for bridge sensors 9.2.4 Relaxation oscillator circuits for leaky capacitive sensors 9.2.5 Relaxation oscillator circuit for differential capacitive sensors 9.3 Performance analysis with component non-idealities 9.4 Design criteria References CH010.pdf Chapter 10 Sensor tags for wireless body-centric communication: challenges and opportunities 10.1 Introduction 10.1.1 Antenna design 10.1.2 Conformability of body-worn antenna 10.1.3 Communication through multiple textile layers 10.2 Existing challenges 10.3 Some solutions 10.3.1 Electromagnetic-band-gap-incorporated antenna design 10.3.2 Determination of effective dielectric constant 10.3.3 Conformability analysis of conformal electromagnetic band gap surfaces 10.4 Compact electromagnetic-band-gap-based antenna for smartwatch applications 10.4.1 Introduction to electromagnetic band gaps 10.4.2 Lumped-element circuit model 10.4.3 Interdigital electrodes unit cell 10.4.4 Array performance enhancement 10.4.5 Determination of effective dielectric constant 10.4.6 Conformal electromagnetic band gap surfaces References CH011.pdf Chapter 11 The role of capacitive sensors for condition monitoring of transformer insulation 11.1 Introduction 11.2 Literature review 11.3 Development of a capacitive sensor for condition assessment of an oil-immersed power transformer’s insulation 11.3.1 Materials required for the fabrication of the 2-FAL sensor 11.3.2 Process of fabrication 11.3.3 Experimental setup 11.4 Electrical equivalent model of the developed sensor 11.4.1 Electrical equivalent circuit of the sensor 11.4.2 Relation between the sensor’s capacitance and the concentration of 2-FAL 11.5 Performance of the sensor 11.5.1 Response of the sensor at different frequencies 11.5.2 Response of the sensor with time 11.5.3 Calibration of the sensor response 11.5.4 Statistical analysis 11.5.5 Repeatability and drift study of the sensor response 11.6 Modification of the sensor’s structure to improve its sensitivity in detecting 2-FAL concentrations in transformer oil 11.7 Performance evaluation of the comb sensor 11.7.1 Response of the comb sensor at different frequencies 11.7.2 Response of the comb sensor with time 11.7.3 Calibration of the comb sensor response 11.7.4 Repeatability of the comb sensor response 11.8 Conclusion References