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@inproceedings{bib_Surf_2025, AUTHOR = {Varma, Jampana Koundinya and Fatema, Anis and Hussain, Aftab M. }, TITLE = {Surface Hardness Mapping With Flexible Insoles Using Machine Learning}, BOOKTITLE = {IEEE International Conference on Flexible and Printable Sensors and Systems}. YEAR = {2025}}

There are several use-cases where the hardness of a surface can be an important parameter - construction, infrastructure, sports fields, and so on. At present, there are no low-cost, thin-film, and wearable-based solutions for this problem. This study presents the development and evaluation of an insole-based sensing system for detecting and characterizing variations in surface conditions. The system integrates velostat, a piezoresistive material, into an insole to accurately capture plantar pressure variations as users traverse diverse terrains. The pressure data are subsequently processed to generate a detailed map differentiating various surface types. Experimental validation demonstrates that the system is capable of successfully mapping two distinct surfaces with an accuracy of 88.8 %. Multiple machine learning algorithms were analyzed to optimize the system performance and validate its efficacy. This approach has significant implications for the maintenance of a sports field, the optimization of athlete performance, and the prevention of injury.

@inproceedings{bib_Fabr_2025, AUTHOR = {Baramatiwala, Ruqaiyya Safdar and Fatema, Anis and Hussain, Aftab M. }, TITLE = {Fabrication of a Flexible Temperature-Pressure Dual Sensor Array for E-Skin Applications}, BOOKTITLE = {IEEE International Conference on Flexible and Printable Sensors and Systems}. YEAR = {2025}}

Mimicking the sensory capabilities of human skin has long been a challenge in the development of intelligent electronic systems. This study introduces a high-performance paper-based electronic skin (e-skin) capable of detecting pressure and temperature simultaneously from the same pixel. The eskin fabricated herein is utilizes paper as a substrate along with velostat thin film and NTC thermistors that enable real-time monitoring of mechanical and thermal stimuli. Both pressure and temperature sensing mechanisms rely on changes in resistance under applied stimulus. The readout is done using an integrated crossbar architecture for both the sensors simultaneously. The lightweight and flexible nature of the paper-based platform makes it suitable for applications in soft robotics and wearable health monitoring. The experimental results demonstrate high sensitivity, stability and rapid response to external stimuli. This work paves the way for the development of multifunctional, large area, low-cost, and sustainable e-skin solutions for nextgeneration flexible electronics and robotics applications.

@inproceedings{bib_Fabr_2025, AUTHOR = {Mishra, Saurabh Bhooshan and El-Atab, Nazek and Hussain, Aftab M. }, TITLE = {Fabrication and Characterization of Large Area Flexible Capacitive Pressure Sensors using PDMS Foam and Functionalized Textile}, BOOKTITLE = {IEEE Journal on Flexible Electronics}. YEAR = {2025}}

Flexible capacitive pressure sensors have simple sensing structure, zero-temperature drift, linear response, and high sensitivity, leading to applications in human healthcare including soft and surgical robotics, human machine interaction (HMI) and wearable devices. In this paper, we present a highly compressible multilayer flexible capacitive pressure sensor, based on air/vapour bubble-induced PDMS foam thin-film as dielectric and polypyrrole coated cotton textile as electrodes. An in-situ chemical oxidative polymerisation method was used to synthesize a conducting, large area polypyrrole coated cotton textile. We used this as parallel electrodes on the top and bottom of the bubble-induced PDMS foam. The bubble-induced PDMS film was made by casting of PDMS, mix with specific amounts of ethanol. The top and bottom textile electrodes were then attached to it with the help of silicone adhesive. We observed low hysteresis, high repeatability, and good step response in our sensor characterisation. Bubble characterisation was also performed including surface profilometer and scanning electron microscopy (SEM). We showcase two applications of our sensor including mouse click and grasping of a cup. The sensor can be fabricated in different shapes and sizes for various applications of free-form electronics such as soft and surgical robotics, wearable, biomedical, human-machine interaction, and so on.

@inproceedings{bib_Dest_2025, AUTHOR = {Gupta, Aditya and Gharde, Kartik and Hussain, Aftab M. }, TITLE = {Destination Oriented Directed Acyclic Graph (DODAG) Formation and Healing in Wi-Sun Networks}, BOOKTITLE = {International Conference on Wireless Communications Signal Processing and Networkingx}. YEAR = {2025}}

The scalability and reliability of any large scale IoT network depends on a multitude of things, the primary one of that, being the communication protocol underlying the system. Wi-Sun is a novel protocol that offers a low power, long range and cost effective solution. It is a mesh protocol such that any node can be configured to be a transceiver. The mesh forms a destination oriented directed acyclic graph (DODAG) with one node configured to be the border router that connects to the internet, enabling cloud access for the entire mesh. However, long connection time and healing time of the DODAG are some of its drawbacks. In this paper, we present experiments on a real-world deployment of a Wi-Sun network where we study patterns in the time required for each additional node to be added in the Wi-Sun network, and investigate the time required to reform a new DODAG when a node with a certain hop count is detached. This deployment can also serve as a testbed for future such evaluations.

@inproceedings{bib_Char_2025, AUTHOR = {Niteesh, Dhayanithi and Mishra, Saurabh Bhooshan and Goyal, Chetanya and Hussain, Aftab M. }, TITLE = {Characterization of Bending Behaviour of Flexible Conductive CNT-PDMS Thin Films}, BOOKTITLE = {IEEE International Conference on Flexible and Printable Sensors and Systems}. YEAR = {2025}}

Free-form electronics are one of the major chal- lenges being tackled in the present era. Along with the substrate and components, the conductive materials used in these also have to endure the applied strain, hence, thin film based conductors are being studied extensively. In this work, we report bending behavior of conductive CNT-PDMS thin film channels. Transmission Line Method (TLM) based resistance calculations have been done to precisely analyze the CNT thin film sheet resistance and the contact resistance. This exercise allows us to look at the effectiveness of CNT channels as a conductive path and also helps us understand their behavior over concentration, path length and strain caused due to bending. We report sheet resistance values of 254 Ω/□ and 1.41 Ω/□ for thin films of two different CNT concentrations. The contact resistances for these films were 230Ω and 315 Ω respectively. We observed that bending induced strain caused the resistance values to increase from 3.95 kΩ for flat to 13.1 kΩ for bending radius of 1.2 cm.

@inproceedings{bib_Char_2025, AUTHOR = {Niteesh, Dhayanithi and Shreya, Malkurthi and Hussain, Aftab M. }, TITLE = {Characterization of Energy Consumption of a Dielectric Elastomer Actuator Based Flapping Wing}, BOOKTITLE = {IEEE International Conference on Flexible and Printable Sensors and Systems}. YEAR = {2025}}

Recent literature in soft robotics has been focused on bio-mimetic technologies, i.e., trying to replicate naturally-occurring structures, such as artificial muscles. Flapping structures have been reported, wherein a soft wing is paired with a solid actuator or vice-versa, but a fully soft actuator and wing setup has only recently been developed. In this work, we present the fabrication and characterization of the electrical response of a fully soft DEA-based flapping wing actuator. The actuator was fabricated using a urethane acrylate polymer elastomer with carbon nanotube (CNT) based electrodes. The 40 mm × 20 mm rectangular actuator was powered through two electrodes. It was subjected to static DC voltages in the range of 1 kV to 2 kV and the current and energy drawn by the actuator were observed. We report the average settling current varying from 7 μA to 43 μA and energy draw varying from 220 mJ to 715 mJ. Further tests on a similarly fabricated actuator revealed the possibility of Time Dependent Dielectric breakdown (TDDB) encountered at 2kV after nearly 120 minutes.

@inproceedings{bib_Arch_2024, AUTHOR = {Lakshmanan, L and Kokad, Brahad Balaji and Hussain, Aftab M. }, TITLE = {Architecture of a Two-wheeler Mobile Sensing Platform for Riding Data Collection}, BOOKTITLE = {International Conference on Vehicular Electronics and Safety}. YEAR = {2024}}

This paper presents the architecture of a two-wheeler mobile sensing platform aimed at collecting compre-hensive two-wheeler riding data. Two-wheelers, prevalent in many countries for their agility and efficiency lack extensive study in autonomous vehicle research. Recognizing this gap, our work introduces a scalable and modular platform equipped with multiple sensors and high-performance embedded systems. The platform captures essential data points such as GPS, acceleration, gyroscope, speed, and 360-degree image and depth data, crucial for developing deep learning models for autonomous navigation and accident prevention. We detail the hardware architecture, consisting of an Nvidia Jetson TX2 NX platform, Raspberry Pi 4 Model B, and various sensors, all tailored to operate efficiently on a two-wheeler. The software methodology is designed to synchronize and process the data effectively, hence allowing us to generate accurate and thorough datasets. Our results demonstrate the platform's potential in improving two-wheeler safety and contributing to the advancement of autonomous vehicle technologies.

@inproceedings{bib_Beyo_2024, AUTHOR = {Hussain, Aftab M. }, TITLE = {Beyond Flexible: Unveiling the Next Era of Flexible Electronic Systems}, BOOKTITLE = {Advanced Materials}. YEAR = {2024}}

Flexible electronics are integral in numerous domains such as wearables, healthcare, physiological monitoring, human–machine interface, and environmental sensing, owing to their inherent flexibility, stretchability, lightweight construction, and low profile. These systems seamlessly conform to curvilinear surfaces, including skin, organs, plants, robots, and marine species, facilitating optimal contact. This capability enables flexible electronic systems to enhance or even supplant the utilization of cumbersome instrumentation across a broad range of monitoring and actuation tasks. Consequently, significant progress has been realized in the development of flexible electronic systems. This study begins by examining the key components of standalone flexible electronic systems–sensors, front-end circuitry, data management, power management and actuators. The next section explores different integration strategies for flexible electronic systems as well as their recent advancements. Flexible hybrid electronics, which is currently the most widely used strategy, is first reviewed to assess their characteristics and applications. Subsequently, transformational electronics, which achieves compact and high-density system integration by leveraging heterogeneous integration of bare-die components, is highlighted as the next era of flexible electronic systems. Finally, the study concludes by suggesting future research directions and outlining critical considerations and challenges for developing and miniaturizing fully integrated standalone flexible electronic systems.

@inproceedings{bib_Mach_2024, AUTHOR = {Goyal, Chetanya and Yellakonda, Kirthi Vignan Reddy and Hussain, Aftab M. }, TITLE = {Machine Learning Based Low-Cost Colorimetric Sensor for Ph and Free-Chlorine Measurement}, BOOKTITLE = {IEEE Sensors Letters}. YEAR = {2024}}

Free-chlorine concentration monitoring is of importance in public and industrial water supplies. Current colorimetric methods, which include test strips, spectrophotometric kits, etc. either lack precision or are expensive and labor intensive. In this study, we present a fully automated, cost-effective method of measurement of free chlorine concentration in real -time. The setup includes an automatic powder dispenser, an automatic liquid dispenser, a sample chamber, and an LED-light-dependent resistor sensor pair. The liquid sample is mixed with a coloring reagent and its color is measured using the sensor pair. Different regression algorithms were trained on the sensor data and tuned to predict the corresponding free-chlorine concentration with maximum accuracy. The system eliminates the need for color matching, reduces the time taken per test, and can be used to predict concentrations of multiple analytes, including ammonia-nitrogen, dissolved oxygen, etc., by adding corresponding colorimetry agents. This allows for a fully automated, real-time water testing system.

@inproceedings{bib_Surf_2024, AUTHOR = {Varma, Jampana Koundinya and Kokad, Brahad Balaji and Fatema, Anis and Hussain, Aftab M. }, TITLE = {Surface Characterization by Plantar Pressure Analysis using Low-cost In-shoe Sensor Array}, BOOKTITLE = {IEEE Sensors Letters}. YEAR = {2024}}

Analysis of foot pressure, also known as plantar pressure analysis, plays a pivotal role in biomedical assessments related to posture and gait analysis. Extensive research has been conducted on leveraging this technique for clinical purposes, leading to the development of flexible pressure sensors. In this letter, we present the use of in-shoe flexible pressure sensor array for determining the nature of the walking surface. The sensor system is fabricated using eight low-cost and robust, in-shoe pressure sensors that leverage the piezoresistivity of velostat. The sensor array was characterized for four different surface types. Random Forest (RF) algorithm was used to classify the surfaces with 86% accuracy. Based on this analysis, we propose a novel method for analyzing various surfaces based on their attributes such as firmness, rigidity, and penetrability.

@inproceedings{bib_Desi_2024, AUTHOR = {Vattem, Anuradha and Hussain, Aftab M. }, TITLE = {Design and implementation of hybrid low power wide area network architecture for IoT applications}, BOOKTITLE = {Journal of Ambient Intelligence and Smart Environments}. YEAR = {2024}}

The rapid proliferation of Internet of Things (IoT) devices and applications has resulted in an increasing demand for Low Power and Wide Area Network (LPWAN) solutions. The adoption of IoT networks still faces several challenges, despite the rapid advancement of low-power communication technology. Homogenizing this sector requires allowing interoperability between many technologies, which is now one of the largest obstacles. In this article, we present the design and implementation of the hybrid LPWAN architecture that can accomplish wide-area communication coverage and low-power consumption for IoT applications by leveraging two LPWAN technologies, Wireless Smart Ubiquitous Network (Wi-SUN) and Long Range (LoRa). In particular, LoRa is used for long-range communication, and Wi-SUN for a low-latency mesh network. Additionally, we implemented smart street light controlling system as a real-world deployment at the university campus to showcase the efficiency of the hybrid network. Our results demonstrate that the hybrid LPWAN architecture provides a better coverage and capacity while consuming less power than that of the LoRa or Wi-SUN network. The results of this study demonstrate the effectiveness of the proposed hybrid LPWAN architecture as a viable solution for next-generation IoT applications.

@inproceedings{bib_Larg_2024, AUTHOR = {Hussain, Aftab M. }, TITLE = {Large Area Flexible Piezoresistive Sensor Array for Smart Mattress Application}, BOOKTITLE = {IEEE Sensors Letters}. YEAR = {2024}}

Affordable healthcare, particularly for elderly persons, is an important goal with aging of the world population. Cloud-connected smart sensor systems are an important part of the healthcare ecosystem. In this letter, we present an affordable large area flexible pressure sensor array using a piezoresistive thin film. The dimensions of the sensor are 180 cm × 90 cm, according to the dimensions of a standard single bed mattress. The sensor array consists of eight vertical sensor strips with a high aspect ratio of 120, highest reported so far for a flexible piezoresistive sensor. The measured output of the sensors showed a high signal-to-noise ratio, with loaded and unloaded sensor resistances of 11 pm 3 Omega and 219.2 pm 0.5 kOmega, respectively. The fabrication process has been designed to be conducive to roll-to-roll manufacturing processes to increase scalability and reduce cost. With a sampling frequency of 10 Hz, the sensor array provides real-time information about user position and possible fall events.

@inproceedings{bib_The__2024, AUTHOR = {Gureja, Akshit and Hussain, Aftab M. and Viswanadh, Kandala Savitha and Walchatwar, Nagesh Laxman and Agrawal, Rishabh Anup and Sinha, Shiven and Chaudhari, Sachin and Vaidhyanathan, Karthik and Choppella, Venkatesh and Bhimalapuram, Prabhakar and Kandath, Harikumar }, TITLE = {The Engineering End-to-End Remote Labs using IoT-based Retrofitting}, BOOKTITLE = {IEEE Access}. YEAR = {2024}}

Remote labs are a groundbreaking development in the education industry, providing students with access to laboratory education anytime, anywhere. However, most remote labs are costly and difficult to scale, especially in developing countries. With this as a motivation, this paper proposes a new remote labs (RLabs) solution that includes two use case experiments: Vanishing Rod and Focal Length. The hardware experiments are built at a low-cost by retrofitting Internet of Things (IoT) components. They are also made portable by designing miniaturised and modular setups. The software architecture designed as part of the solution seamlessly supports the scalability of the experiments, offering compatibility with a wide range of hardware devices and IoT platforms. Additionally, it can live-stream remote experiments without needing dedicated server space for the stream. The software architecture also includes an automation suite that periodically checks the status of the experiments using computer vision (CV). The software architecture is further assessed for its latency and performance. RLabs is qualitatively evaluated against seven non-functional attributes - affordability, portability, scalability, compatibility, maintainability, usability, and universality. Finally, user feedback was collected from a group of students, and the scores indicate a positive response to the students’ learning and the platform’s usability.

@inproceedings{bib_A_Po_2024, AUTHOR = {Kumar, Gajingam Naveen and Karmakar, Sourav and Hussain, Aftab M. }, TITLE = {A Portable and Flexible On-Road Sensing System for Traffic Monitoring}, BOOKTITLE = {IEEE Sensors Letters}. YEAR = {2024}}

With an increasing number of vehicles on the road every day, intelligent traffic monitoring and control is essential. This entails development of cost-effective, scalable, and easy-to-install monitoring systems. In this letter, a versatile piezoresistance-based cost-effective on-road sensor system is presented to estimate vehicle speed and vehicle wheelbase length. The system consists of a velostat thin film sensing element placed on the road, with read out circuits and control electronics located at the sidewalk. The system measures the speed of a vehicle with 90.4% accuracy, and the length of the wheelbase with 94.3% accuracy. The wheelbase length can be used to classify the vehicle type. Our experiments show that the system is reliable, as the sensor output returns to the initial values after each vehicle passes. The utilization of flexible piezoresistive sensors makes this system convenient to deploy in different applications where basic traffic activity monitoring is required with speed, count, and classification estimation of vehicles.

@inproceedings{bib_Surf_2024, AUTHOR = {Varma, Jampana Koundinya and Kokad, Brahad Balaji and Fatema, Anis and Hussain, Aftab M. }, TITLE = {Surface Characterization by Plantar Pressure Analysis Using Low-Cost in-Shoe Sensor Array}, BOOKTITLE = {IEEE Sensors Journal}. YEAR = {2024}}

Analysis of foot pressure, also known as plantar pressure analysis, plays a pivotal role in biomedical assessments related to posture and gait analysis. Extensive research has been conducted on leveraging this technique for clinical purposes, leading to the development of flexible pressure sensors. In this letter, we present the use of in-shoe flexible pressure sensor array for determining the nature of the walking surface. The sensor system is fabricated using eight low-cost and robust, in-shoe pressure sensors that leverage the piezoresistivity of velostat. The sensor array was characterized for four different surface types. Random Forest (RF) algorithm was used to classify the surfaces with 86% accuracy. Based on this analysis, we propose a novel method for analyzing various surfaces based on their attributes such as firmness, rigidity, and penetrability. Such a device can be used for ascertaining surface characteristics after construction, or playing surfaces in a stadium.

@inproceedings{bib_Inve_2024, AUTHOR = {Fatema, Anis and Mishra, Saurabh Bhooshan and Hussain, Aftab M. }, TITLE = {Investigation of Reliability of a Polypyrrole coated Conductive Cotton Fabric for Sensing Applications}, BOOKTITLE = {IEEE International Conference on Flexible and Printable Sensors and Systems}. YEAR = {2024}}

Electrically conductive fibers are attracting attention because of the newly emerging areas of interactive textiles and smart fabrics. In this paper, we present the fabrication and characterization of a flexible conductive cotton fabric (CCF) of size 20 cm×20 cm coated with polypyrrole synthesized using in-situ chemical oxidative polymerization. This is the largest area reported in the literature for a polypyrrole-coated conducting fabric. The characteristics of the conducting fabric were investigated at 25 points by sandwiching it between the electrodes in the form of a 5×5 array. To test its reliability, the CCF was washed with distilled water 10 times, and its response was measured after every wash. We observed that there was a change in the resistance after the first four washes, however, the response stabilized thereafter. The average deviation in resistance until first four washes was found to be 27.45%, whereas for washes 6 to 10, it was 5.11%.

@inproceedings{bib_Smar_2024, AUTHOR = {Naware, Vaibhav and Gupta, Aditya and Vattem, Anuradha and Hussain, Aftab M. }, TITLE = {Smart Street Light System using Wi-SUN and oneM2M}, BOOKTITLE = {IEEE Applied Sensing conference}. YEAR = {2024}}

As urbanization continues to accelerate, the demand for energy-efficient and sustainable urban infrastructure has become paramount. Street lights are an elemental part of any city because they facilitate better night visibility, secured roads, and luminescence in public areas. Also, because street lights are present homogeneously on city roads, if they are used for wireless communication, other smart nodes can make use of their backhaul. In this paper, we present a smart street lighting system based on Wi-SUN (Wireless Smart Ubiquitous Network), which offers excellent redundancy owing to its use of a mesh topology. Wi-SUN is based on the IEEE 802.15.4g standard and uses license-free sub-GHz bands. We have used oneM2M as the middleware platform to enable possible interoperability with other smart city data verticals such as weather stations, environmental monitoring, crowd monitoring and so on. The proposed system provides a robust and low-cost method for controlling street lighting in any area, providing IP-addressable lighting. The proposed system additionally aims to provide consistent Wi-SUN coverage for future nodes in the area of deployment

@inproceedings{bib_A_Wi_2024, AUTHOR = {Gupta, Rohan and Naware, Vaibhav and Hussain, Aftab M. and Vattem, Anuradha }, TITLE = {A Wi-SUN Network-based Electric Vehicle Charging Station using Open Charge Point Protocol (OCPP) and oneM2M Platform}, BOOKTITLE = {IEEE Applied Sensing conference}. YEAR = {2024}}

Street lights are ubiquitous public infrastructure in urban areas that can be leveraged for smart city applications. In this paper, we present an electric vehicle charging station (EVCS) that communicates using Wi-SUN network integrated on a network of streetlights, and using oneM2M middleware. The proposed architecture follows the level 2 charging standards and the open charge point protocol (OCPP), ensuring compatibility and interoperability across diverse charging infrastructures. By seamlessly incorporating Wi-SUN network and oneM2M middleware, our architecture enables efficient communication and interaction with a wide array of devices and services. The utilization of the oneM2M platform further enhances the integration by establishing a seamless connection between the EVCS and the broader smart city infrastructure. We have fabricated a proof-of-concept system that consists of the EVCS connected to a Wi-SUN network integrated with the streetlight network in the institute campus. The performance of our solution was evaluated by measuring the latency associated with authentication and billing for EV users. We report the average latency observed over several iterations of charging to be 0.7±0.2 s (excluding the time required for charging). We also measured the Wi-SUN communication range in the campus environment with trees and buildings and found the maximum range to be around 370 m.

@inproceedings{bib_Appl_2024, AUTHOR = {Yellakonda, Kirthi Vignan Reddy and Ruthwik, Muppala and Garg, vishal and Hussain, Aftab M. }, TITLE = {Appliance Control using Smart Ceiling Tiles and Localization of Energy Harvesting Switches}, BOOKTITLE = {IEEE Applied Sensing conference}. YEAR = {2024}}

There is an emerging consensus that the future of intelligent and energy efficient homes is automation and cloud control. This paper presents a novel infrastructural concept using smart ceiling tiles and an energy-harvesting Bluetooth Low Energy (BLE) switch to control home appliances. The switch location is determined using trilateration of the signals received by the tiles installed in different rooms. In this paper, we localized the switch among three rooms separated by a brick wall by analyzing the received signal strength indicator (RSSI) values captured by three tiles located in three rooms. The tiles are powered with DC power using the support rails, thus minimizing wiring for power delivery. We used different machine learning classification algorithms with the received RSSI values as features for predicting the location of the switch accurately. Through experimentation, we achieved high accuracy of 93% in classifying the switch position among the rooms. The integration of smart tiles in the false ceiling along with the use of an energy-harvesting BLE switch offers numerous advantages, such as reducing wiring complexity, enhancing user convenience, and aesthetic design.

@inproceedings{bib_Non__2023, AUTHOR = {Gupta, Aditya and Ruthwik, Muppala and Saxena, Advaita and Hussain, Aftab M. }, TITLE = {Non Line of Sight (NLoS) Path Loss Evaluation of Wi-SUN in an Urban Landscape}, BOOKTITLE = {IEEE Applied Sensing conference}. YEAR = {2023}}

The scalability of remote Internet of Things (IoT) deployments into verticals of smart cities relies primarily on the communication protocols and data platforms employed. Accordingly, the adoption of LoRaWAN, Sigfox, NB-IoT, etc. has risen in recent years. These protocols have been created to cater to the low power and long range requirements of IoT. In this paper, we evaluate one such protocol, Wi-SUN (Wireless Smart Ubiquitous Network), that additionally offers excellent redundancy owing to its use of a mesh topology. Wi-SUN is based on the IEEE 802.15.4g standard and uses license-free sub-GHz bands. However, IoT networks using any communication protocol require a knowledge of signal propagation and attenuation in real-world scenarios. Thus, we evaluated the path loss of WiSUN transmissions by analysing the RSSI values inside a typical city building and an urban outdoor habitat

@inproceedings{bib_Char_2023, AUTHOR = {Lakshmanan, L and Gupta, Mohee Datta and Fatema, Anis and Hussain, Aftab M. }, TITLE = {Characterisation and Quantification of Crosstalk on a Velostat-Based Flexible Pressure Sensing Matrix}, BOOKTITLE = {IEEE International Conference on Flexible and Printable Sensors and Systems}. YEAR = {2023}}

Crosstalk, in a sensor matrix, is the unwanted signal obtained at a sensor pixel that is not directly related to the stimulus. This paper presents a novel approach towards quantifying the crosstalk characteristics of a sensor matrix. The method involves obtaining the normalized sum of all the neighbouring pixel readings, weighted by their distance from the stimulated pixel. We have used this methodology to characterise the crosstalk for a 5×5 velostat-based flexible pressure sensing matrix that uses a crossbar electrode architecture. The measure thus obtained is a dimensionless value between 0 to 1, 0 indicating no crosstalk and 1 indicating the maximum possible crosstalk. We characterized sensor matrices with three different pitch lengths: 3mm, 4mm, and 5mm. We observe the crosstalk values to lie between 0.032 to 0.17 across different weights and pitches, which indicates a low measure of crosstalk. The 5 mm pitch matrix displayed the least crosstalk, which was expected due to the larger spacing between the pixels. We also characterised the crosstalk for all 25 pixels of a 4 mm pitch matrix and found the mean to be 0.081±0.002 , within the range from 0.0071 to 0.1656.

@inproceedings{bib_Poly_2023, AUTHOR = {Fatema, Anis and Mishra, Saurabh Bhooshan and Gupta, Mohee Datta and Hussain, Aftab M. }, TITLE = {Polypyrrole-Based Cotton Flexible Pressure Sensor Using In-Situ Chemical Oxidative Polymerization}, BOOKTITLE = {IEEE International Conference on Flexible and Printable Sensors and Systems}. YEAR = {2023}}

Polymer-based piezoresistive pressure sensors that possess flexibility and stretchability have received increased recognition in wearable sensing systems. In this paper, we present a flexible pressure sensor designed using polypyrrole-coated cotton (PCC) that was synthesized using in-situ chemical oxidative liquid polymerization. The sensor shows high sensitivity at low-pressure ranges and can measure pressures in the range 160 Pa to 16 kPa. The response time of the sensor was found to be 463 ms. It also exhibits excellent repeatability during continuous loading-unloading for over 1000 cycles. The performance of the sensor was evaluated in terms of resistance change as a function of tensile strain, by applying repeated compression and expansion strains. We report the gauge factor of the resistive sensor to be 0.32 for applied compressive strains from 0% to 99.6%. Such a large compressive strain range can be achieved with cotton because of its fibrous nature. It was observed that there is no change in conductivity, at a given strain, on repeated expansion and compression of the polymer for 20 cycles.

@inproceedings{bib_Effi_2023, AUTHOR = {Chauhan, Shirley and Fatema, Anis and Kuriakose, Ivin and Hussain, Aftab M. }, TITLE = {Efficient Calibration of Velostat-Based Flexible Pressure Sensor Matrix}, BOOKTITLE = {IEEE International Conference on Flexible and Printable Sensors and Systems}. YEAR = {2023}}

Regular plantar pressure monitoring is required for diabetic, wheelchair-bound and bed-ridden individuals. It has been shown that peak plantar pressure for diabetics increases significantly and progressively, and requires regular monitoring for early detection and intervention. Sensor matrices of capacitative, resistive, and piezoelectric transducers are most commonly used for measuring areal pressure. Calibration for such medical devices is crucial for reliability and repeatable results. In this work, we elaborate on the calibration challenges of a 32×32 velostat-based sensor matrix, and demonstrate calibration strategies suitable for a manufactured product. We show that 2N parameters can be used to calibrate an N×N sensor matrix instead of 2N2 . We observe the accuracy of calibration of a 32×32 sensor matrix by comparing the total detected weight of 35 participants at a static load with their reported weight, with 4.2% mean error and 3.1% median error. For participants in the 50–85 kg weight range, the difference was always within ±5%. Further, upon drawing contour plots and using the pressure distribution information, we were able to distinguish participants with possible foot ulcers and flat feet.

@inproceedings{bib_Fabr_2023, AUTHOR = {Karmakar, Sourav and Ranjan, Astitva and Hussain, Aftab M. }, TITLE = {Fabrication and Testing of a PneuNet Actuator-Based Caterpillar Like Amphibian Soft Robot for Multi-Terrain Applications}, BOOKTITLE = {IEEE International Conference on Flexible and Printable Sensors and Systems}. YEAR = {2023}}

Bio-inspired structures provide several new possibilities in the area of robotics due to their superiority and diversity in execution. Researchers have been developing various robotic applications with the combination of soft materials such as silicone and various 3D printed materials. These kinds of soft robots can be useful for various human-robotic interactions such as search and rescue, medical surgery and so on. In this work, we present the fabrication and characterization of a small caterpillar-like soft robot (7 cm ×3.5 cm ×3 cm) powered using PneuNet actuation. Due to the limitations of traditional robotics, we believe that such soft material-based robots can be effective in various applications. The fabricated silicone-based PneuNet soft robot, which moves like a caterpillar, has also been embedded with an ESP camera module and LED light to enable applications such as surveillance and search-and-rescue. This soft robotic actuator can also perform tasks on various types of terrains, including ice and water surface. We find that the normalized distance travelled per actuation cycle on gravel to be 0.23 BL.

@inproceedings{bib_Inve_2023, AUTHOR = {Fatema, Anis and Chauhan, Shirley and Gupta, Mohee Datta and Hussain, Aftab M. }, TITLE = {Investigation of the Long-term Reliability of a Velostat-Based Flexible Pressure Sensor Array for 210 Days}, BOOKTITLE = {IEEE Transactions on Device and Materials Reliability}. YEAR = {2023}}

Pressure sensors are subjected to continuous force and stress that may affect the operation of the sensor in the long run. Reliability is a crucial factor that must be considered when designing and fabricating any sensor. It is essential to test the material used in the sensor to assess the reliability of the complete product. In this work, we report the long-term reliability of a flexible pressure sensor mat using a carbon-impregnated polymer, velostat, which is a flexible, light, and thin polymer composite material with piezoresistive properties. We focus on the analysis of the performance of a flexible pressure sensor array under long-term and repeated loading. Tests were performed every fortnight for 210 days. We have observed that the material characteristics of the velostat material change on repeated application of pressure up to a certain time frame. For a given loading, once the material settles, the change in resistance of the material becomes consistent for a given application of pressure. We have also analyzed the changes in the parameters associated with the 2-parameter model, and have analyzed the effect of crosstalk on the sensor matrix for different pitch lengths to select the best pitch that will give us the minimum crosstalk. We have observed that the error rate of the sensor pixels decreased by 53 percentage points in 210 days. The results obtained from the experimental tests for reliability reveal a practical possibility of implementing velostat-based pressure sensors in wearable and healthcare devices and provide steps to take while calibrating an as-fabricated velostat-based sensor.

@inproceedings{bib_Deve_2023, AUTHOR = {Mishra, Saurabh Bhooshan and Fatema, Anis and Hussain, Aftab M. }, TITLE = {Development of Conductive Surface on Polyurethane Foam Using In Situ Polymerization of Pyrrole for Capacitive Pressure Sensing}, BOOKTITLE = {IEEE Sensors Journal}. YEAR = {2023}}

@inproceedings{bib_Fabr_2023, AUTHOR = {Niteesh, Dhayanithi and Shreya, Malkurthi and Goyal, Chetanya and Hussain, Aftab M. }, TITLE = {Fabrication and Characterization of a Dielectric Elastomer Actuator Based Flapping Wing}, BOOKTITLE = {IEEE International Conference on Flexible and Printable Sensors and Systems}. YEAR = {2023}}

Biomimetic technologies are an important part of the soft robotics research area because of their ability to replicate naturally occurring structures. Researchers have been developing and improving many such technologies ranging from prosthetics to artificial skin. In this work, we present the fabrication and characterization of an artificial muscle flapping wing using dielectric elastomer actuators (DEAs). The actuator was fabricated using a urethane acrylate polymer elastomer with carbon nanotube (CNT) based electrodes. The 40 mm × 20 mm rectangular actuator was powered through two electrodes at the top. It was subjected to different voltages in the range of 500 - 2500 V and the displacement of the bottom edge was observed. We report the actuator edge displacement to be 20 mm, i.e., 0.5 body lengths (BL) at static 2.5 kV. The dynamic behavior of the device was also analyzed by actuating it with a square wave of various frequencies (0 to 10 Hz). We report the resonant frequency of the actuator to be 4 Hz, with a sub-harmonic at 2 Hz

@inproceedings{bib_Flex_2023, AUTHOR = {Gupta, Mohee Datta and Lakshmanan, L and Fatema, Anis and Hussain, Aftab M. }, TITLE = {Flexible Writing Pad based on a Piezoresistive Thin Film Sensor Matrix}, BOOKTITLE = {IEEE Applied Sensing conference}. YEAR = {2023}}

Digital multimedia tools are becoming increasingly important as the world slowly shifts to an online mode. In this work, we present a low-cost, flexible writing pad that uses a 16×16 pressure sensing matrix based on the piezoresistive thin film of velostat. The writing area is 5 cm×5 cm with an effective pixel area of 0.06 mm2. A read out circuit is designed to detect the change in resistance of the velostat pixel using a voltage divider. A microprocessor raster scans through the sensor pixel matrix to obtain a data frame of 256 integers. This data is processed using techniques like squaring and normalising (S&N), Gaussian blurring, and adaptive thresholding to generate a more readable output. The writing pad is able to resolve characters larger than 2 cm in length. The flexible writing pad produces legible output while flexed at bending radius of upto 4 cm. Such flexibility promises to enhance the usability and portability of the writing pad significantly.

@inproceedings{bib_Anal_2023, AUTHOR = {Fatema, Anis and Kuriakose, Ivin and Gupta, Rohan and Hussain, Aftab M. }, TITLE = {Analysis of Interpolation Techniques for a Flexible Sensor Mat for Plantar Pressure Measurement}, BOOKTITLE = {IEEE Applied Sensing conference}. YEAR = {2023}}

Plantar pressure or foot pressure analysis is a predominant tool for biomedical assessment of posture, gait, and other activities. The distribution and magnitude of pressure can provide fruitful information to diagnose or predict any risk of foot disorders or impairments. This paper presents the design and fabrication of a low-cost, flexible pressure sensor (FLEPS) mat for assessing plantar pressure variations. We have designed a 32× 32 velostat-based piezoresistive pressure sensor array with dimensions of 330 mm × 330 mm and an active sensing area of 284 mm × 284 mm. Each sensor pixel is of size 5 mm × 5 mm with a pitch of 4 mm. To enhance the resolution and the visual quality of the heat map obtained, we have used different interpolation techniques like the nearest neighbor, bilinear, and bicubic for the received data and transformed the 32× 32 array to a 100× 100-pixel array. It was observed that the bicubic interpolation technique gives a better image quality but takes more computation time than the other two interpolation techniques.

@inproceedings{bib_Fabr_2023, AUTHOR = {Shreya, Malkurthi and Niteesh, Dhayanithi and Bhattacharjee, Sumana and Hussain, Aftab M. }, TITLE = {Fabrication and Characterization of a FlexiblTransparent Nozzle/Diffuser Micropump}, BOOKTITLE = {IEEE Applied Sensing conference}. YEAR = {2023}}

Micropumps are one of the most widely used components in lab-on-a-chip devices and other biomedical applications as they can manipulate fluid flow in a very small footprint. In this study, a flexible nozzle-diffuser planar micropump was fabricated using polydimethylsiloxane (PDMS). The pump was fabricated using a two layer structure: bottom layer with molded channels and chamber encapsulated by a planar top layer. The use of PDMS as the structural material for both layers imparts flexibility and transparency to the complete pump assembly. The micropump was characterized by counting the number of compression cycles required for a known volume of fluid, here water, to flow from the inlet to the outlet. A similar characterization was performed while bending the pump at bending radii of 71 cm and 45 cm. The pump produced a flow rate per compression cycle of 5.53 μ1 on flat surface and that of 4μ1,3.6μ1 when placed on surfaces of bending radii of 71cm and 45 cm respectively. The transparency of the pump and biocompatability of PDMS make it an excellent material for biomedical and colorimetric applications.

@inproceedings{bib_Time_2023, AUTHOR = {Nagasri, Goparaju Sai Usha and Lakshmanan, L and Abhinav, N and B.Rahul, and Lovish, B and Gangadharan, Deepak and Hussain, Aftab M. }, TITLE = {Time Series-based Driving Event Recognition for Two Wheelers}, BOOKTITLE = {Design, Automation & Test in Europe Conference & Exhibition}. YEAR = {2023}}

Classification of a motorcycle's driving events can provide deep insights to detect issues related to driver safety. In order to perform the above, we developed a hardware system with 3-D accelerometer/gyroscope sensors that can be deployed on a motorcycle. The data obtained from these sensors is used to identify various driving events. We firstly investigated several machine learning (ML) models to classify driving events. However, in this process, we identified that though the overall accuracy of these traditional ML models is decent enough, the class-wise accuracy of these models is poor. Hence, we have developed time-series-based classification algorithms using LSTM and Bi-LSTM to classify various driving events. The experiments conducted have demonstrated that the proposed models have surpassed the state-of-the-art models in the context of driving event recognition with better class-wise accuracies …

@inproceedings{bib_Sing_2023, AUTHOR = {El-Atab, Nazek and Mishra, Rishabh and Hussain, Aftab M. }, TITLE = {Single and double touch mode capacitive pressure/force sensing technique and approach}, BOOKTITLE = {Bulletin of the American Physical Society}. YEAR = {2023}}

SS02. 00002: Single and double touch mode capacitive pressure/force sensing technique and approach*

@inproceedings{bib_Stru_2023, AUTHOR = {El-Atab, Nazek and Mishra, Rishabh and Al-Modaf, Fhad and Babatain, Wedyan and Hussain, Aftab M. }, TITLE = {Structural engineering methods to combine the diaphragm and cantilevers for flexible capacitive pressure sensor}, BOOKTITLE = {Bulletin of the American Physical Society}. YEAR = {2023}}

PP10. 00010: Structural engineering methods to combine the diaphragm and cantilevers for flexible capacitive pressure sensor*

@inproceedings{bib_Non__2023, AUTHOR = {Gupta, Aditya and Ruthwik, Muppala and Saxena, Advaita and Hussain, Aftab M. }, TITLE = {Non Line of Sight (NLoS) Path Loss Evaluation of Wi-SUN in an Urban Landscape}, BOOKTITLE = {IEEE Applied Sensing conference}. YEAR = {2023}}

The scalability of remote Internet of Things (IoT) deployments into verticals of smart cities relies primarily on the communication protocols and data platforms employed. Accordingly, the adoption of LoRaWAN, Sigfox, NB-IoT, etc. has risen in recent years. These protocols have been created to cater to the low power and long range requirements of IoT. In this paper, we evaluate one such protocol, Wi-SUN (Wireless Smart Ubiquitous Network), that additionally offers excellent redundancy owing to its use of a mesh topology. Wi-SUN is based on the IEEE 802.15.4g standard and uses license-free sub-GHz bands. However, IoT networks using any communication protocol require a knowledge of signal propagation and attenuation in real-world scenarios. Thus, we evaluated the path loss of Wi- SUN transmissions by analysing the RSSI values inside a typical city building and an urban outdoor habitat. Keywords—Path Loss,

@inproceedings{bib_Anal_2023, AUTHOR = {Fatema, Anis and Kuriakose, Ivin and Gupta, Rohan and Hussain, Aftab M. }, TITLE = {Analysis of Interpolation Techniques for a Flexible Sensor Mat for Plantar Pressure Measurement}, BOOKTITLE = {IEEE Applied Sensing conference}. YEAR = {2023}}

Plantar pressure or foot pressure analysis is a predominant tool for biomedical assessment of posture, gait, and other activities. The distribution and magnitude of pressure can provide fruitful information to diagnose or predict any risk of foot disorders or impairments. This paper presents the design and fabrication of a low-cost, flexible pressure sensor (FLEPS) mat for assessing plantar pressure variations. We have designed a 32 × 32 velostat-based piezoresistive pressure sensor array with dimensions of 330 mm × 330 mm and an active sensing area of 284 mm × 284 mm. Each sensor pixel is of size 5 mm × 5 mm with a pitch of 4 mm. To enhance the resolution and the visual quality of the heat map obtained, we have used different interpolation techniques like the nearest neighbor, bilinear, and bicubic for the received data and transformed the 32 × 32 array to a 100 × 100-pixel array. It was observed that the bicubic interpolation technique gives a better image quality but takes more computation time than the other two interpolation techniques. Index Terms—Flexible pressure sensor, Interpolation, Piezore- sistive, Plantar pressure, Velostat.

@inproceedings{bib_Labo_2023, AUTHOR = {Tiwari, Anushka and Chauhan, Shirley and Bharatala, Sailaja and Ajay, Thammana and Paleru, Nilima and Hussain, Aftab M. }, TITLE = {Labour Monitoring in Pregnant Women using Electrocardiography}, BOOKTITLE = {IEEE Applied Sensing conference}. YEAR = {2023}}

The continuous monitoring of maternal vital signs, particularly during labor, can be of critical importance for the health of the child and mother. We present a compact wearable electronic system that measures, in real-time, maternal heart rate using electrocardiography (ECG) signals. The heart rate is determined using moving average filters to remove the noises in the signal and using autocorrelation for the detection of periodic signals. We use electromyography (EMG) signals for calculating uterine contractions using the root mean sum of filtered signal values. The resulting system can identify heart rate in a female subject with an accuracy of ± 2.9bpm, and uterine contraction intensity within ± 5 units compared to values obtained from a gold-standard CTG machine. The system is accurate, low-cost, and portable, so that it can be deployed at primary healthcare centers in low-income countries. The system can also be

@inproceedings{bib_Flex_2023, AUTHOR = {Gupta, Mohee Datta and Lakshmanan, L and Fatema, Anis and Hussain, Aftab M. }, TITLE = {Flexible Writing Pad based on a Piezoresistive Thin Film Sensor Matrix}, BOOKTITLE = {IEEE Applied Sensing conference}. YEAR = {2023}}

Digital multimedia tools are becoming increasingly important as the world slowly shifts to an online mode. In this work, we present a low-cost, flexible writing pad that uses a 16×16 pressure sensing matrix based on the piezoresistive thin film of velostat. The writing area is 5 cm × 5 cm with an effective pixel area of 0.06 mm2 . A read out circuit is designed to detect the change in resistance of the velostat pixel using a voltage divider. A microprocessor raster scans through the sensor pixel matrix to obtain a data frame of 256 integers. This data is processed using techniques like squaring and normalising (S&N), Gaussian blurring, and adaptive thresholding to generate a more readable output. The writing pad is able to resolve characters larger than 2 cm in length. The flexible writing pad produces legible output while flexed at bending radius of upto 4 cm. Such flexibility promises to enhance the usability and portability of the writing pad significantly. Index Terms—Flexible PCB, Flexible writing pad, Piezoresistive material, Pressure sensor, Velostat

@inproceedings{bib_Smar_2023, AUTHOR = {Hussain, Muhammad Mustafa and Hussain, Aftab M. }, TITLE = {Smart thermal patch for adaptive thermotherapy}, BOOKTITLE = {United States Patent}. YEAR = {2023}}

A smart thermal patch for adaptive thermotherapy is provided. In an embodiment, the patch can be a stretchable, non-polymeric, conductive thin film flexible and non-invasive body integrated mobile thermal heater with wireless control capabilities that can be used to provide adaptive thermotherapy. The patch can be geometrically and spatially tunable on various pain locations. Adaptability allows the amount of heating to be tuned based on the temperature of the treated portion.

@inproceedings{bib_Stru_2022, AUTHOR = {Mishra, Rishabh B. and Al-Modaf, Fhad and Babatain, Wedyan and Hussain, Aftab M. and El-Atab, Nazek }, TITLE = {Structural engineering approach for designing foil-based flexible capacitive pressure sensors}, BOOKTITLE = {Sensors Journal}. YEAR = {2022}}

Structural engineering plays an essential role in designing, improving, and optimizing an electromechanical system, instinctively affecting its performance. In this study, design optimization, finite element analysis, and experimental evaluation of capacitive pressure sensors were conducted. The air pressure sensing application was demonstrated to characterize different sensors, which include a combination of multiple rectangular cantilevers and diaphragms (square and circular-shaped). After the design improvement, we found that the square and circular diaphragms each with two trapezoidal cantilevers exhibited highest sensitivity to air pressure monitoring among the different investigated designs which combine the square and circular diaphragms with cantilevers. These designs were then selected for further analysis for acoustic pressure monitoring. The sensors were fabricated using the doit-yourself technique with household materials such as post-it paper, posted tape, and foil. Our approach offers an alternative to the conventional cleanroom fabrication technique and uses easily available materials to fabricate affordable sensors. Therefore, this is the first step toward the development of democratized and sustainable electronic devices that are affordable and available to everyone on the internet. Index Terms—Capacitive sensing, air pressure sensing, acoustic pressure sensing, paper electronics, democratized electronics, affordable electronics, structural engineering.

@inproceedings{bib_Nume_2022, AUTHOR = {Bhattacharjee, Sumana and Mishra, Rishabh B. and Shreya, Malkurthi and Hussain, Aftab M. }, TITLE = {Numerical Modelling of Differential Pressure Sensor System for Real-Time Viscosity Measurement}, BOOKTITLE = {Students Conference on Engineering and Systems}. YEAR = {2022}}

Viscosity measurement has wide ranging applications from oil industry to pharmaceutical industry. However, measuring viscosity in real-time is not a facile process. This paper provides an elaborate mathematical model and study of viscosity measurement in real-time using pressure sensors. For a given flowrate, a change in liquid viscosity gives rise to a change in pressure difference across a particular section of the pipe. Hence, by recording the pressure change, viscosity can be calculated dynamically. A mathematical model as well as a finite element analysis model has been presented to determine viscosity from flowrate and pressure difference. A set of pressure sensors can be placed at a fixed distance from each other to get the real- time pressure change, while flowrate can be obtained using a flowmeter. For the finite element analysis, the pressure sensors were placed 60 mm away from each other. The radius of the pipe was 19 mm. A mixture of water and glycerol, with different ratios, was used to provide variable viscosity. Index Terms—Viscosity, Flowrate, Microfluidic channel, Pressure sensor, Real-time measurement

@inproceedings{bib_Ener_2022, AUTHOR = {Raihan, Md Anam and Chattopadhyay, Kuntal and BHATIA, AVIRUCH and Garg, Vishal and Hussain, Aftab M. }, TITLE = {Energy Analysis of Semi-transparent Building Integrated Photovoltaic Window in Hyderabad, India Using Automated Parametric Simulations}, BOOKTITLE = {International Conference on Sustainable and Renewable Energy Engineering}. YEAR = {2022}}

In recent years, semi-transparent building-integrated photovoltaics (BIPV) technology has attracted attention for its renewable energy utilization. This research aims to develop a methodology for assessing the energy-saving potential of semi-transparent photovoltaic (STPV) window, which has a complex relationship with daylighting and air conditioning (AC) electricity consumption. A case study has been developed for the composite climate of Hyderabad, India. The study examines four commercially available single and double pane STPV windows and similar non-photovoltaic windows. For evaluation, an automated parametric simulation tool was developed to compute the net electricity consumption (NEC) for a representative model building with different window systems, and several window-to-wall ratios (WWR) and orientations. The result shows benefit in adopting the STPV window system across all directions …

@inproceedings{bib_Dete_2022, AUTHOR = {Gupta, Mohee Datta and Mishra, Rishabh B and Kuriakose, Ivin and Hussain, Aftab M. }, TITLE = {Determination of thermal and mechanical properties of SU-8 using electrothermal actuators}, BOOKTITLE = {MRS Advances}. YEAR = {2022}}

Microelectromechanical systems (MEMS) are small-scale devices capable of producing motion using electrical energy as input. In this work, we present the determination of thermal and mechanical properties of SU-8, which is an emerging structural material for MEMS applications. We have experimentally calculated the coefficient of thermal expansion (CTE), thermal conductivity, and specific heat capacity of SU-8 as 29.68 ppm °C−1, 0.17 , and 1.6 , respectively. We observe a non-linear relationship between the input power with the displacement achieved by an SU-8-based thermal actuator because of the hyperelastic behavior of the material. The non-linearity in the experimental results has been explained using the two-parameter Mooney–Rivlin model. With our experimental data, we found the parameters for the uniaxial tensile stress, as Pa and Pa

@inproceedings{bib_Wear_2022, AUTHOR = {Kuriakose, Ivin and Chauhan, Shantanu and Fatema, Anis and Hussain, Aftab M. }, TITLE = {Wearable Pressure Sensor Suit for Real-Time Detection of Incorrect Exercise Techniques}, BOOKTITLE = {Sensors}. YEAR = {2022}}

In recent years, the popularity of weight training has increased significantly. However, incorrect technique or physical form while performing an exercise can not only slow down progress but also cause serious injuries. Deadlift is a famous weight training exercise, which if done incorrectly, can lead to chronic back pain. In this paper, we present a wearable pressure sensor system that checks the posture of the user while performing deadlift. The suit employs a set of flexible pressure sensors, made using velostat (piezoresistive) material, to get the amount of bending for specific muscles. We have developed an algorithm to process the data in real-time so that feedback about incorrect posture can be provided to the user immediately. The algorithm has been configured using data from a single subject, however, it provides accurate classification for multiple subjects in the same weight class, thus eliminating the need for subject-wise configuration. The algorithm classifies a repetition (rep) of the exercise into a good rep or bad rep with an overall accuracy of 95.5%, across three subjects. With some enhancements, the system can also be configured to classify reps of other exercises.

@inproceedings{bib_SGLS_2022, AUTHOR = {Raihan, Md Anam and Chattopadhyay, Kuntal and Bhatia, Aviruch and Garg, Vishal and Hussain, Aftab M. }, TITLE = {SGLSim: tool for smart glazing energy performance analysis}, BOOKTITLE = {Energy Informatics.Academy Conference}. YEAR = {2022}}

A tool Smart Glazing Simulator (SGLSim), has been developed to perform parametric simulation analysis of diferent window systems with several window-to-wall ratios and orientations to compute and compare the annual energy performance. The net annual energy performance of the building is based on the electricity consumption in heating, cooling, interior lighting, and appliances, along with the electricity generation by the photovoltaic (PV) glazing, which is used to evaluate the energy performance of smart glazing. Performing parametric energy simulations and calculating the net annual electricity consumption of diferent combinations requires building modeling and energy simulation expertise. A web-based parametric tool can assist the user in carrying out the desired studies without requiring extensive technical knowledge. A case study is prepared for India’s warm and humid climatic zone. This study examines the benefts of double pane semi-transparent photovoltaics (STPV) glazing, STPV glazing with dynamic internal blind, and electrochromic (EC) glazing over other traditional glazing systems. The study shows that the optimal net annual electricity consumption in the case of STPV windows is 10–12% less than the optimal value obtained in a simple glazing case. Additionally, the result suggested that glare-controlled interior blinds in the STPV window further reduce the net annual electricity consumption by up to 15% compared to conventional glazing. Similarly, installing the EC glazing reduces the yearly electricity consumption by up to 5% compared to standard glazing. Keywords: Smart glazing, Energy performance, Parametric simulations

@inproceedings{bib_SGLS_2022, AUTHOR = {Raihan, Md Anam and Chattopadhyay, Kuntal and Bhatia, Aviruch and Garg, Vishal and Hussain, Aftab M. }, TITLE = {SGLSim: tool for smart glazing energy performance analysis}, BOOKTITLE = {Energy Informatics}. YEAR = {2022}}

A tool Smart Glazing Simulator (SGLSim), has been developed to perform parametric simulation analysis of different window systems with several window-to-wall ratios and orientations to compute and compare the annual energy performance. The net annual energy performance of the building is based on the electricity consumption in heating, cooling, interior lighting, and appliances, along with the electricity generation by the photovoltaic (PV) glazing, which is used to evaluate the energy performance of smart glazing. Performing parametric energy simulations and calculating the net annual electricity consumption of different combinations requires building modeling and energy simulation expertise. A web-based parametric tool can assist the user in carrying out the desired studies without requiring extensive technical knowledge. A case study is prepared for India’s warm and humid climatic zone. This study examines the benefits of double pane semi-transparent photovoltaics (STPV) glazing, STPV glaz-ing with dynamic internal blind, and electrochromic (EC) glazing over other traditional glazing systems. The study shows that the optimal net annual electricity consumption in the case of STPV windows is 10–12% less than the optimal value obtained in a sim-ple glazing case. Additionally, the result suggested that glare-controlled interior blinds in the STPV window further reduce the net annual electricity consumption by up to 15% compared to conventional glazing. Similarly, installing the EC glazing reduces the yearly electricity consumption by up to 5% compared to standard glazing.

@inproceedings{bib_A_Mu_2022, AUTHOR = {Prakash, Mante Shubham and Suhas, Vaddhiparthy s V S L N Surya and Ruthwik, Muppala and Gangadharan, Deepak and Hussain, Aftab M. and Vattem, Anuradha }, TITLE = {A Multi Layer Data Platform Architecture for Smart Cities using oneM2M and IUDX}, BOOKTITLE = {World Forum on Internet of Things}. YEAR = {2022}}

Smart cities play a vital role in limiting the ill-effects of rapid urbanization on the environment without compromising on benefits such as improving infrastructure, standard of living, and productivity. However, the collection, storage, and sharing of data from the plethora of sensor networks in a typical smart city deployment warrants a well-defined data platform architecture. In this paper, we propose a multi layer architecture compliant with the oneM2M standards and the Indian Urban Data Exchange (IUDX) framework. The proposed architecture consists of Data Monitoring (DML), Data Storage (DSL), and Data Exchange (DEL) layers. The DML employs oneM2M as the middleware platform to achieve interoperability. The DSL uses a multi-tenant architecture with multiple logical databases, enabling efficient and reliable data management. The DEL utilizes standard data schemas and open APIs of IUDX to avoid data silos, and enables secure data sharing. Further, we present a proof-of-concept implementation of our architecture deployed in a university campus using OM2M, PostgreSQL, and Django. Finally, simulations mimicking real-time data insertion and retrieval showed that the DML can handle 600 concurrent users with an average latency under 100 milli seconds. The DSL improved the latency compared to a single database architecture and the DEL could handle 100 concurrent users with zero failed requests.

@inproceedings{bib_Ener_2022, AUTHOR = {Raihan, Md Anam and Chattopadhyay, Kuntal and Bhatia, Aviruch and Garg, Vishal and Hussain, Aftab M. }, TITLE = {Energy Analysis of Semi-transparent Building Integrated Photovoltaic Window in Hyderabad, India Using Automated Parametric Simulations}, BOOKTITLE = {IOP Conference Series: Earth and Environmental Science.}. YEAR = {2022}}

In recent years, semi-transparent building-integrated photovoltaics (BIPV) technology has attracted attention for its renewable energy utilization. This research aims to develop a methodology for assessing the energy-saving potential of semi-transparent photovoltaic (STPV) window, which has a complex relationship with daylighting and air conditioning (AC) electricity consumption. A case study has been developed for the composite climate of Hyderabad, India. The study examines four commercially available single and double pane STPV windows and similar non-photovoltaic windows. For evaluation, an automated parametric simulation tool was developed to compute the net electricity consumption (NEC) for a representative model building with different window systems, and several window-to-wall ratios (WWR) and orientations. The result shows benefit in adopting the STPV window system across all directions and higher optimal WWR in STPV window as compared to normal window with the same opto-thermal characteristics.

@inproceedings{bib_5D-I_2022, AUTHOR = {Mante, Shubham and Hernandez, Nathalie and Hussain, Aftab M. and Chaudhari, Sachin and Gangadharan, Deepak and Monteil, Thierry }, TITLE = {5D-IoT, a Semantic Web Based Framework for Assessing IoT Data Quality}, BOOKTITLE = {ACM Symposium on Applied Computing}. YEAR = {2022}}

Due to the increasing number of Internet of Things (IoT) devices, a large amount of data is being generated. However, factors such as hardware malfunctions, network failures, or cyber-attacks affect data quality and result in inaccurate data generation. Therefore, to facilitate the data usage, we propose a novel 5D-IoT framework for heterogeneous IoT systems that provides uniform data quality assessment with meaningful data descriptions. Based on the quality assessment result, a data consumer can directly access data from any IoT source, which ultimately speeds up the analysis process and helps gain important insights in less time. The framework relies on semantic descriptions of sensor observations and SHACL shapes assessing the quality of such data. Evaluations carried out on real-time data show the added value of such a framework.

@inproceedings{bib_Stru_2022, AUTHOR = {Mishra, Rishabh B and Al-Modaf, Fhad and Babatain, Wedyan and Hussain, Aftab M. and El-Atab, Nazek }, TITLE = {Structural engineering approach for designing foil-based flexible capacitive pressure sensors}, BOOKTITLE = {Sensors Journal}. YEAR = {2022}}

nd optimizing an electromechanical system, instinctively affecting its performance. In this study, design optimization, finite element analysis, and experimental evaluation of capacitive pressure sensors were conducted. The air pressure sensing application was demonstrated to characterize different sensors, which include a combination of multiple rectangular cantilevers and diaphragms (square and circular-shaped). After the design improvement, we found that the square and circular diaphragms each with two trapezoidal cantilevers exhibited highest sensitivity to air pressure monitoring among the different investigated designs which combine the square and circular diaphragms with cantilevers. These designs were then selected for further analysis for acoustic pressure monitoring. The sensors were fabricated using the do- it-yourself technique with household materials such as post-it paper, posted tape, and foil. Our approach offers an alternative to the conventional cleanroom fabrication technique and uses easily available materials to fabricate affordable sensors. Therefore, this is the first step toward the development of democratized and sustainable electronic devices that are affordable and available to everyone on the internet.

@inproceedings{bib_Inve_2021, AUTHOR = {RUTHWIK, MUPPALA and Navnit, Abhinav and SURYA, POONDLA VENKATA SAI and Hussain, Aftab M. }, TITLE = {Investigation of Indoor LoRaWAN Signal Propagation for Real-World Applications}, BOOKTITLE = {International Conference for Convergence of Technology}. YEAR = {2021}}

The advent of Internet of Things has resulted in new communication protocols such as LoRaWAN and Narrowband IoT slowly rising to be viable and even better alternatives to traditional protocols such as Wi-Fi and Bluetooth. LoRa in particular, has attracted a lot of attention owing to low power consumption of end nodes, low cost and use of license-free sub-GHz bands. Further, high link budgets in LoRaWAN communication allow for fewer gateways to provide network coverage over a large area. However, the success of deployment of LoRaWAN gateways in real world applications depends on meticulous planning. A major drawback in this scenario is the lack of extensive data on loss of signal strength, particularly in cityscapes, where buildings and trees can create significant path loss. In this paper, we investigate the path loss for LoRaWAN signals inside a typical city building (brick walls, reinforced cement concrete ceiling, wooden doors). The RSSI values of transmissions from multiple locations to a stationary gateway have been analysed to find the effect of indoor obstacles such as walls and doors on the propagation of LoRaWAN signals. We report that significant loss of energy can occur, even at relatively close range, because of the structures.

@inproceedings{bib_Comp_2021, AUTHOR = {Devendra, Deeksha and Malkurthi, Shreya and Navnit, Abhinav and Hussain, Aftab M. }, TITLE = {Compact Electric Vehicle Charging Station using Open Charge Point Protocol (OCPP) for E-Scooters}, BOOKTITLE = {International Conference on Sustainable Energy and Future Electric Transportation}. YEAR = {2021}}

An Electric Vehicle (EV) charger, also called Electric Vehicle Charging Station (EVCS) is an infrastructure element that supplies electrical energy for recharging EVs. The paper focuses on the design and fabrication of two-wheeler (escooter) electric vehicle charging equipment. Considering the future scenario of mass privatization of EV two-wheelers on Indian roads, the outline discusses the product design based on fabricability, affordability, and ability to mass manufacture. The proposed architecture follows the Level 2 charging standards (240 Volts), and is based on the open charge point protocol (OCPP). The suggested EVCS is constructed considering the safety prerequisites of system administrators, installers, consumers, government agencies and others. The design of EVCS links to three industries: equipment manufacturers, software industry and electric power networks. This paper presents design considerations by elaborating the hardware, software, and protocols followed to design the Level 2 charging standard EVCS.

@inproceedings{bib_Acce_2021, AUTHOR = {Babatain, Wedyan and Bhattacharjee, Sumana and Hussain, Aftab M. and Hussain, Muhammad Mustafa }, TITLE = {Acceleration Sensors: Sensing Mechanisms, Emerging Fabrication Strategies, Materials, and Applications}, BOOKTITLE = {ACS Applied Electronic Materials}. YEAR = {2021}}

Accelerometers are among the most mature sensor technologies with a broad range of applications in multiple fields and industries. They represent the most widely used microelectromechanical system (MEMS) devices with excellent and reliable performance. MEMS acceleration sensors established dominance mainly in navigation and control applications. In recent years, however, recent technologies and materials have emerged that introduce novel sensing mechanisms, improve performance, enable customization, reduce cost, and reduce fabrication complexity. Herein, the recent advances in accelerometers based on MEMS and recent emerging technologies are reviewed. This work provides a comprehensive review of accelerometers’ sensing mechanisms and the main characteristics and features of each type of sensor, material, and fabrication strategies used to fabricate them. From the aspect of sensor application, this work focuses on reviewing applications that demonstrate the use of accelerometers manufactured using unconventional technologies and materials in prevailing fields such as healthcare monitoring, automotive industry, navigation, building, and structural monitoring. Moreover, challenges and future efforts needed to be addressed in this field are summarized

@inproceedings{bib_Rece_2021, AUTHOR = {Mishra, Rishabh B. and El-Atab, Nazek and Hussain, Aftab M. and Hussain, Muhammad M. }, TITLE = {Recent Progress on Flexible Capacitive Pressure Sensors: From Design and Materials to Applications}, BOOKTITLE = {Advanced Materials Technologies}. YEAR = {2021}}

For decades, the revolution in design and fabrication methodology of flexible capacitive pressure sensors using various inorganic/organic materials has significantly enhanced the field of flexible and wearable electronics with a wide range of applications in aerospace, automobiles, marine environment, robotics, healthcare, and consumer/portable electronics. Mathematical modelling, finite element simulations, and unique fabrication strategies are utilized to fabricate diverse shapes of diaphragms, shells, and cantilevers which function in normal, touch, or double touch modes, operation principles inspired from microelectromechanical systems (MEMS) based capacitive pressure sensing techniques. The capacitive pressure sensing technique detects changes in capacitance due to the deformation/deflection of a pressure sensitive mechanical element that alters the separation gap of the capacitor. Due to advancement in state-of-the-art fabrication technologies, the performance and properties of capacitive pressure sensors are enhanced. In this review paper, recent progress in flexible capacitive pressure sensing techniques in terms of design, materials, and fabrication strategies is reported. The mechanics and fabrication steps of paper-based low-cost MEMS/flexible devices are also broadly reported. Lastly, the applications of flexible capacitive pressure sensors, challenges, and future perspectives are discussed.

@inproceedings{bib_Elec_2021, AUTHOR = {Devendra, Deeksha and Prakash, Mante Shubham and Niteesh, Dhayanithi and Hussain, Aftab M. }, TITLE = {Electric Vehicle Charging Station using Open Charge Point Protocol (OCPP) and oneM2M Platform for Enhanced Functionality}, BOOKTITLE = {IEEE Region 10 Conference}. YEAR = {2021}}

A smart city is a collection of a variety of smart devices representing several disparate infrastructural verticals. The data gathered by these smart devices helps bring a strong integration of human, collective, and artificial intelligence within the city operation. With the advent and proliferation of electric vehicles (EVs), the EV charge point is a relatively new addition to this plethora of smart devices. We believe that the EV charge point can acquire enhanced functionality if it can be seamlessly integrated with the rest of the smart city infrastructure. For example, charging services can be stopped if smart grid or smart fire alarms sense an electrical overload or fire hazard in the vicinity. However, the interaction of an EV charge point with the smart city infrastructure requires seamless information exchange across various verticals. This horizontal flow of information is enabled by making the charge point complaint with the oneM2M platform. To this end, we present the design and fabrication of an EV charge point based on the OCPP communication standard and complaint with the oneM2M platform. Further, we discuss various use cases showing an increased functional capability of the EV charger due to access to data from other IoT devices.

@inproceedings{bib_Ener_2021, AUTHOR = {Prakash, Mante Shubham and Ruthwik, Muppala and Niteesh, Dhayanithi and Hussain, Aftab M. }, TITLE = {Energy Monitoring Using LoRaWAN-based Smart Meters and oneM2M Platform}, BOOKTITLE = {Sensors}. YEAR = {2021}}

The Internet of Things (IoT) plays a key role in real-time monitoring at different stages of the power generation system, assisting to achieve better efficiency, minimize load on the grids by analysing usage patterns, provide faster resolutions to power outages, and so on. In this paper, we present a novel energy monitoring approach employing LoRaWAN-enabled smart energy meters and a oneM2M-based platform for collecting and analysing the data. The energy meters transmit data at 15-minutes intervals, i.e., 96 data points per day. A novel format has been developed for the LoRaWAN Protocol Data Unit (PDU) to transmit the values of phase currents and voltages, and data related to power and energy comsumption. This results in a high-resolution dataset containing more than 10,000 instances per meter, accumulated over the last four months. The data can be visualised in a live dashboard enabling the signal parameters such as Received Signal Strength Index (RSSI) and Signal to Noise Ratio (SNR) to be monitored in addition to the electrical parameters, to ensure proper data transmission. Finally, the trends in power and energy consumption of the load have been analysed, which can result in improved efficiency of building management, and early detection of electrical faults and failures

@inproceedings{bib_A_Co_2021, AUTHOR = {Fatema, Anis and Navnit, Abhinav and Devendra, Deeksha and Hussain, Aftab M. }, TITLE = {A Combined Capacitance and Resistance Digital Readout Circuit for Sensory Nodes}, BOOKTITLE = {Sensors}. YEAR = {2021}}

Most of the sensors that measure physical variables such as humidity, strain, motion, temperature, and pressure are designed based on the variation of capacitance or the resistance of a circuit entity. This paper presents a 12-bit combined resistance and capacitance to digital converter (RCDC) to analyze and process the information from these sensors. The read-out circuit first converts the capacitance or resistance to an analog voltage, followed by conversion to digital data using a successive approximation (SAR) type analog to digital converter (ADC). The circuit has been designed based on the 180 nm CMOS technology. The capacitance to digital converter (CDC) circuit covers a wide range of capacitance from 30 pF to 100 pF with a 17 fF resolution, whereas the resistance to digital converter (RDC) circuit covers a range of resistance from 1 Ω to 30 Ω and has a resolution of 7 mΩ. The 12-bit CDC and RDC have a measurement time of 20 μs and show a non-linearity of 0.66% and 0.57%, respectively. Index Terms—analog to digital converter; capacitance to dig- ital converter; resistance to digital converter; read-out circuit; successive approximation

@inproceedings{bib_Low-_2021, AUTHOR = {Shreya, Malkurthi and Yellakonda, Kirthi Vignan Reddy and Tiwari, Anushka and Hussain, Aftab M. }, TITLE = {Low-cost Color Sensor for Automating Analytical Chemistry Processes}, BOOKTITLE = {Sensors}. YEAR = {2021}}

Detection of color change is an important tool used in several analytical chemistry processes in various industries such as biomedical, diagnostics, agriculture, food processing, and so on. In this study, we present an automated color detection system to perform qualitative analysis of liquid reagents. Many of the available techniques for colorimetric applications make use of expensive, high-resolution digital cameras. We have developed a simple low-cost system based on a light emitting diode (LED) and light-dependent resistor (LDR) pair to obtain information about the color of a liquid reagent. This system has been compared with a camera-based system for color detection. The LED-LDR system provides information about the color of an object by obtaining relative intensities of red, green, and blue (RGB) light reflected by the object in a sequential process. The system was tested by obtaining color information for different concentrations of potassium permanganate solution and by determining the endpoint of a titration experiment. This versatile system can be used for many other colorimetric measurements, for example, the amount of dissolved ammonia in water using Nesslers reagent (potassium tetraiodomercurate).

@inproceedings{bib_Feas_2021, AUTHOR = {RUTHWIK, MUPPALA and Navnit, Abhinav and Devendra, Deeksha and Matera, Eustachio Roberto and Accettura, Nicola and Hussain, Aftab M. }, TITLE = {Feasibility of Standalone TDoA-based Localization Using LoRaWAN}, BOOKTITLE = {International Conference on Localization and GNSS}. YEAR = {2021}}

The growing need for localization has created an array of alternative approaches to GNSS, based on Wi-Fi, Bluetooth, Ultra-Wideband, etc. Long Range Wide Area Network (LoRaWAN) is one such technology that has garnered tremendous attention due to its low power and long-range capabilities. Many attempts to achieve localization using LoRaWAN have been made till now, based on a variety of techniques such as Angle of Arrival (AoA), Time Difference of Arrival (TDoA), Received Signal Strength Index (RSSI). In this paper, we present a novel, standalone localization approach by developing a collaborative, TDoA-based methodology using LoRaWAN. The server determines the target node location by means of TDoA measurements from the target node to the gateways. The introduction of an additional stationary node allows the synchronization of the gateways without utilizing GNSS, either inbuilt or external. The cooperation between target node, synchronization node and server, is the innovative feature which makes this approach attractive for GNSS-free localization. Further, we explore the effects of timing resolution, time-on-air, and duty cycle constraints on the localization error. Finally, the distribution of error in a triangle of gateways situated approximately 8.6 kilometers apart is simulated in ideal Line of Sight (LoS) conditions, showing the maximum error to be around 23 meters

@inproceedings{bib_Tuna_2021, AUTHOR = {Cheng, Kezi and Hussain, Aftab M. and Burrows, Keith and Clarke, David }, TITLE = {Tunable blinds for windows}, BOOKTITLE = {United States Patent}. YEAR = {2021}}

Methods and apparatus for modulating light using a tunable light modulation device . The tunable light modulation devices comprises an elastomer structure including at least one elastomer layer , a compliant electrode network of con ducting fibers arranged on a first surface of the at least one elastomer layer , a patterned electric conductor arranged on a second surface of the at least one elastomer layer opposite the first surface . The patterned electric conductor includes a plurality of individually - addressable sections , and the com pliant electrode network is configured to compress the at least one elastomer layer in the presence of an electric field between the compliant electrode network and one or more of the individually - addressable sections of the patterned elec tric conductor to produce a voltage - dependent roughening of the at least one elastomer layer .

@inproceedings{bib_A_Lo_2021, AUTHOR = {Fatema, Anis and SURYA, POONDLA VENKATA SAI and Mishra, Rishabh Bhooshan and Hussain, Aftab M. }, TITLE = {A Low-Cost Pressure Sensor Matrix for Activity Monitoring in Stroke Patients Using Artificial Intelligence}, BOOKTITLE = {Sensors Journal}. YEAR = {2021}}

Muscle weakening is a common consequence of stroke and can result in a reduction in physical activity of the affected body part. Therapy includes a range of physical exercises that will help the patients restore and build physical strength, endurance, flexibility, balance, and stability. In order to analyze and recognize the activity and movement of hands while performing these exercises, we have developed a 4 × 4 flexible pressure sensor matrix to quantize the performance and progress of a patient undergoing physiotherapy. We have also developed an artificial intelligence (AI) based algorithm to determine the accuracy of positioning by the patients. Experimental results demonstrate that the algorithm gives a mean error of 0.103 cm in detecting the position of load, compared to a mean error of 0.704 cm using mathematical analysis. With this system, a patient can be asked to move a weight to a particular location (as part of regular physiotherapy) and the pressure sensor matrix can be used to calculate error in positioning along with the time taken to complete the task. Advantages of the proposed pressure sensor matrix are cost effectiveness, facile fabrication, high sensitivity, robustness and flexibility

@inproceedings{bib_Comp_2021, AUTHOR = {Devendra, Deeksha and Shreya, Malkurthi and Navnit, Abhinav and Hussain, Aftab M. }, TITLE = {Compact Electric Vehicle Charging Station using Open Charge Point Protocol (OCPP) for E-Scooters}, BOOKTITLE = {International Conference on Sustainable Energy and Future Electric Transportation}. YEAR = {2021}}

An Electric Vehicle (EV) charger, also called Electric Vehicle Charging Station (EVCS) is an infrastructure element that supplies electrical energy for recharging EVs. The paper focuses on the design and fabrication of two-wheeler (escooter) electric vehicle charging equipment. Considering the future scenario of mass privatization of EV two-wheelers on Indian roads, the outline discusses the product design based on fabricability, affordability, and ability to mass manufacture. The proposed architecture follows the Level 2 charging standards (240 Volts), and is based on the open charge point protocol (OCPP). The suggested EVCS is constructed considering the safety prerequisites of system administrators, installers, consumers, government agencies and others. The design of EVCS links to three industries: equipment manufacturers, software industry and electric power networks. This paper presents design considerations by elaborating the hardware, software, and protocols followed to design the Level 2 charging standard EVCS. Index Terms—Electric Vehicle (EV), Electric Vehicle Charge Station (EVCS), Web Sockets, Open Charge Point Protocol (OCPP), Level 2 EV Charging

@inproceedings{bib_Kite_2020, AUTHOR = {Navnit, Abhinav and Devendra, Deeksha and Tiwari, Anushka and Hussain, Aftab M. }, TITLE = {KiteCam – a novel approach to low-cost aerial surveillance}, BOOKTITLE = {Sensors}. YEAR = {2020}}

The ever-growing need for surveillance over various geographical locations has necessitated the development of novel monitoring approaches. While drones are still considered the most suitable aerial surveillance equipment, new techniques based on use of kites such as kite aerial photography (KAP) are becoming popular. This paper deals with one such novel approach, termed as KiteCam, which provides a low-cost and versatile method of performing local aerial surveillance for a prolonged period. The camera, processor, battery and power management module have been designed and fabricated such that the total weight of the system is approximately 42 grams. Hence, the system is light enough to be carried by most kites under normal weather conditions, thus offering a wide variety of applications with minimal energy consumption and concealed surveillance options. The test flights have been successfully conducted and observed in terms of stability and duration. The images obtained from the flight tests have been analyzed and verified for consistency and clarity. Finally, some modifications have also been mentioned regarding the future generations of the device.

@inproceedings{bib_Kite_2020, AUTHOR = {Navnit, Abhinav and Devendra, Deeksha and Tiwari, Anushka and Hussain, Aftab M. }, TITLE = {KiteCam – a novel approach to low-cost aerial surveillance}, BOOKTITLE = {Sensors}. YEAR = {2020}}

The ever-growing need for surveillance over various geographical locations has necessitated the development of novel monitoring approaches. While drones are still considered the most suitable aerial surveillance equipment, new techniques based on use of kites such as kite aerial photography (KAP) are becoming popular. This paper deals with one such novel approach, termed as KiteCam, which provides a low-cost and versatile method of performing local aerial surveillance for a prolonged period. The camera, processor, battery and power management module have been designed and fabricated such that the total weight of the system is approximately 42 grams. Hence, the system is light enough to be carried by most kites under normal weather conditions, thus offering a wide variety of applications with minimal energy consumption and concealed surveillance options. The test flights have been successfully conducted and observed in terms of stability and duration. The images obtained from the flight tests have been analyzed and verified for consistency and clarity. Finally, some modifications have also been mentioned regarding the future generations of the device.

@inproceedings{bib_Poly_2020, AUTHOR = {Mishra, Rishabh Bhooshan and Babatain, Wedyan and El-Atab, Nazek and Hussain, Aftab M. and Hussain, Muhammad M. }, TITLE = {Polymer/paper-based double touch mode capacitive pressure sensing element for wireless control of robotic arm}, BOOKTITLE = {2020 IEEE 15th International Conference on Nano/Micro Engineered and Molecular System}. YEAR = {2020}}

In this work, a large area, low cost and flexible polymer/paper-based double touch mode capacitive pressure sensor is demonstrated. Garage fabrication processes are used which only require cutting, taping and assembly of aluminum (Al) coated polyimide (PI) foil, PI tape and double-sided scotch tape. The presented pressure sensor operates in different pressure regions i.e. normal (0 to 7.5 kPa), transition (7.5 to 14.24 kPa), linear (14.24 to 54.9 kPa) and saturation (above 54.9 kPa). The advantages of the demonstrated double touch mode capacitive pressure sensors are low temperature drift, long linear range, high pressure sensitivity, precise pressure measurement and large die area. The linear output along with a high sensitivity range (14.24 to 54.9 kPa pressure range) of the sensor are utilized to wirelessly control the movement of a robotic arm with precise rotation and tilt movement capabilities.

@inproceedings{bib_Spat_2020, AUTHOR = {Cheng, Kezi and Hussain, Aftab M. and Clarke, David }, TITLE = {Spatially and temporally tunable window devices on flexible substrates}, BOOKTITLE = {Electroactive Polymer Actuators and Devices}. YEAR = {2020}}

Windows whose transmittance can be modified by an applied voltage have previously been fabricated from soft, transparent elastomers sandwiched between ITO coated glass and a compliant, silver nanowire top electrode.1 In this contribution we extend the capabilities of the tunable window so that the optical transmittance can be varied spatially over the window according to voltage signals applied to different segments of the back electrode of the window, defined by patterning of individually addressable electrodes. The actuation signals are controlled using TTL-level input signals applied to high voltage switches. We also show that the spatially tunable window can be fabricated on a flexible substrate, such as PET, and the optical transmittance is not affected by bending of the substrate. The use of a polymer substrate not only increases possible applications of this class of voltage controlled light modulation device but also has the potential of reducing cost at an industrial scale by replacing more costly ITO coated glass substrate.

@inproceedings{bib_Diap_2020, AUTHOR = {Khan, S. M. and Mishra, R. B. and Qaiser, N. and Hussain, Aftab M. and Hussain, M. M. }, TITLE = {Diaphragm shape effect on the performance of foil-based capacitive pressure sensors}, BOOKTITLE = {AIP Advances}. YEAR = {2020}}

We present detailed shape-based analyses to compare the performance of metal foil-based capacitive pressure sensors based on the shape of the diaphragm (top electrode). We perform a detailed analysis on the use of new material and deflection in various shaped diaphragms to act as a performance indicator for pressure-based capacitive sensors. A low-cost, recyclable, and readily available material is used to present an alternative to the expensive materials used in conventional pressure sensors. Diaphragms of five different shapes (circle, ellipse, pentagon, square, and rectangle) are fabricated and analyzed. Mathematical, FEM, and experimental tests are performed for capacitive sensors fabricated in five different shapes. The mathematically calculated deflection for each shaped diaphragm is compared with the results of the corresponding FEM simulations. Two different experiments are performed to verify …

@inproceedings{bib_Stre_2020, AUTHOR = {Hussai, Muhammad Mustafa and Hussain, Aftab M. and Shamim, Atif and Ghaffar, Farhan Abdul }, TITLE = {Stretchable antenna for wearable electronics}, BOOKTITLE = {}. YEAR = {2020}}

Various examples are provided for stretchable antennas that can be used for applications such as wearable electronics. In one example, a stretchable antenna includes a flexible support structure including a lateral spring section having a proximal end and at a distal end; a metallic antenna disposed on at least a portion of the lateral spring section, the metallic antenna extending along the lateral spring section from the proximal end; and a metallic feed coupled to the metallic antenna at the proximal end of the lateral spring section. In another example, a method includes patterning a polymer layer disposed on a substrate to define a lateral spring section; disposing a metal layer on at least a portion of the lateral spring section, the metal layer forming an antenna extending along the portion of the lateral spring section; and releasing the polymer layer and the metal layer from the substrate.

@inproceedings{bib_Diss_2020, AUTHOR = {Hussain, Muhammad M and Mishra, Kush and Hussain, Aftab M. and Abdulkareem, Meshaal Muhammed and Nassar, Joanna }, TITLE = {Dissolvable sensor system for environmental parameters}, BOOKTITLE = {}. YEAR = {2020}}

A sensor system includes at least one sensor configured to detect at least one environmental parameter, a processor coupled to the at least one sensor, and a dissolvable polymer encasing the sensor system.

@inproceedings{bib_Meta_2020, AUTHOR = {Mishra, R. B. and Shaikh, S. F. and Hussain, Aftab M. and Hussain, M. M. }, TITLE = {Metal coated polymer and paper-based cantilever design and analysis for acoustic pressure sensing}, BOOKTITLE = {AIP Advances}. YEAR = {2020}}

Cantilevers are one of the most utilized mechanical elements for acoustic sensing. In comparison to the edge clamped diaphragms of different shapes, a single edge clamped cantilever makes an acoustic sensor mechanically sensitive for detection of lower pressure. The aspect ratio of cantilevers is one of the most important parameters which affect sensitivity. Herein, we present a mathematical, finite element method and experimental analysis to determine the effect of the aspect ratio on the resonant frequency, response time, mechanical sensitivity, and capacitive sensitivity of a cantilever-based acoustic pressure sensor. Three cantilevers of different aspect ratios (0.67, 1, and 1.5) have been chosen for sound pressure application to detect capacitance change. The cantilever with the smallest aspect ratio (0.67) has the highest response time (206 ms), mechanical sensitivity, and capacitive sensitivity (22 fF), which …

@inproceedings{bib_Low-_2020, AUTHOR = {Mishra1, Rishabh B. and Khan, Sherjeel M. and Shaikh, Sohail F. and Hussain, Aftab M. and Hussain, Muhammad M. }, TITLE = {Low-cost foil/paper based touch mode pressure sensing element as artificial skin module for prosthetic hand}, BOOKTITLE = {IEEE International Conference on Soft Robotics}. YEAR = {2020}}

Capacitive pressure sensors have several advantages in areas such as robotics, automation, aerospace, biomedical and consumer electronics. We present mathematical modelling, finite element analysis (FEA), fabrication and experimental characterization of ultra-low cost and paper-based, touch-mode, flexible capacitive pressure sensor element using Do-It-Yourself (DIY) technology. The pressure sensing element is utilized to design large-area electronics skin for low-cost prosthetic hands. The presented sensor is characterized in normal, transition, touch and saturation modes. The sensor has higher sensitivity and linearity in touch mode operation from 10 to 40 kPa of applied pressure compared to the normal (0 to 8 kPa), transition (8 to 10 kPa) and saturation mode (after 40 kPa) with response time of 15.85 ms. Advantages of the presented sensor are higher sensitivity, linear response, less diaphragm area …

@inproceedings{bib_Semi_2020, AUTHOR = {Hussain, Aftab M. }, TITLE = {Semiconductor device including monolithically integrated PMOS and NMOS transistors}, BOOKTITLE = {}. YEAR = {2020}}

A method for producing a semiconductor device involves forming a first transistor having a silicon substrate and a gate, and forming a second transistor, having a germanium substrate, on top of the first transistor. The second transistor is formed by forming a first gate of the second transistor on top of, and electrically coupled to, the gate of the first transistor, bonding the germanium substrate to the first gate of the second transistor so that the bonding does not damage the first transistor, and forming a second gate of the second transistor on the germanium substrate.

@inproceedings{bib_Impr_2020, AUTHOR = {Reddy, Chinthalapani Rajashekar and Tanmai, Mukku and Dwivedi, Ayush Kumar and ROUT, AUROPRAVA and Chaudhari, Sachin and Vemuri, Kavita and Sundara, Rajan Krishnan and Hussain, Aftab M. }, TITLE = {Improving Spatio-Temporal Understanding of Particulate Matter using Low-Cost IoT Sensors}, BOOKTITLE = {International Symposium on Personal, Indoor and Mobile Radio Communications}. YEAR = {2020}}

Current air pollution monitoring systems are bulky and expensive resulting in a very sparse deployment. In addition, the data from these monitoring stations may not be easily accessible. This paper focuses on studying the dense deployment based air pollution monitoring using IoT enabled low-cost sensor nodes. For this, total nine low-cost IoT nodes monitoring particulate matter (PM), which is one of the most dominant pollutants, are deployed in a small educational campus in Indian city of Hyderabad. Out of these, eight IoT nodes were developed at IIIT-H while one was bought off the shelf. A web based dashboard website is developed to easily monitor the real-time PM values. The data is collected from these nodes for more than five months. Different analyses such as correlation and spatial interpolation are done on the data to understand efficacy of dense deployment in better understanding the spatial variability and time-dependent changes to the local pollution indicators.

@inproceedings{bib_Deve_2019, AUTHOR = {Tejaswini, K Dharani and Garg, Vishal and Hussain, Aftab M. and Marthur, Jyotirmay and Gupta, Rajat }, TITLE = {Development of Open-source Low-cost Building Monitoring Sensors using IoT Standards}, BOOKTITLE = {Air Conditioning and Refrigeration Journal}. YEAR = {2019}}

Energy consumption has dramatically increased in the residential building sector over the past few years. Many researchers today are interested not only in designing energy-efficient buildings but also in evaluating the actual building performance and managing operations for delivering the design intent. Monitoring building performance using currently available sensors and mobile applications poses challenges in terms of cost and standardization. This paper presents a new approach to make sensors affordable and inter-operable by designing open-source hardware and using well-established standards for data communication and storage, thereby making energy monitoring ubiquitous and affordable in the residential sector. The proposed solution uses low-power loggers, Bluetooth Low Energy wireless communication version 4 for data transfer from loggers to mobile phones for further transfer to cloud, oneM2M standard to ensure interoperability, and NGSI-LD for data management.

@inproceedings{bib_Simu_2019, AUTHOR = {Bhattacharjee, Sumana and Mishra, Rishabh Bhooshan and Devendra, Deeksha and Hussain, Aftab M. }, TITLE = {Simulation and Fabrication of Piezoelectrically Actuated Nozzle/Diffuser Micropump}, BOOKTITLE = {Sensors}. YEAR = {2019}}

Micropumps are one of the most important parts of a microfluidic system. In particular, for biomedical applications such as Lab-on-Chip systems, micropumps are used to transport and manipulate test fluids in a controlled manner. In this paper, a low-cost, structurally simple, piezoelectrically actuated micropump was simulated and fabricated using poly-dimethylsiloxane (PDMS). The channels in PDMS were fabricated using patterned SU-8 structures. The pump flow rate was measured to be 9.49 μL/min, 14.06 μL/min and 20.87 μL/min for applied voltages of 12 V, 14 V and 16 V respectively. Further, we report finite element analysis (FEA) simulation to confirm the operation of the micropump and compare favorably the experimentally obtained flowrate with the one predicted by simulation. By taking these flow rates as a reference, the chamber pressure was found to be 1.1 to 1.5 kPa from FEA simulations.

@inproceedings{bib_Flex_2019, AUTHOR = {Hussain, Aftab M. and Ghoneim, Mohamed T. and Rojas, Jhonathan P. and Fahad, Hossain }, TITLE = {Flexible and/or Stretchable Sensor Systems}, BOOKTITLE = {Sensors}. YEAR = {2019}}

With recent advancements in the field of wearable devices based on Internet of Things (IoT), the concept of flexible and stretchable electronic systems has become increasingly significant. Although decades of dimensional scaling have led to the miniaturization of the traditional complementary metal oxide semiconductor-(CMOS-) based electronic components, they still remain mechanically rigid and brittle. These rigid devices can be mounted on flexible PCB substrates to obtain a certain degree of flexibility; however, this technique cannot lead to truly body conformal electronic systems. Thus, research teams around the world have been looking at various ways of obtaining completely flexible electronic components at the device level itself. These efforts include various processes to thin down silicon chips to make them flexible or development and use of flexible and stretchable substrate materials to fabricate electronic devices. The thinning down process for traditional silicon-based electronic chips can be performed before or after the complete transistor fabrication process [1]. These approaches are referred to as “device first” approach or “device last” approach. In case of the device last approach, thin films of single crystal silicon are transfer printed to a flexible substrate and processed further to fabricate CMOS circuitry [2, 3]. However, in this approach, many high-temperature steps have to be avoided due to the limited thermal stability of the flexible substrate, leading to a suboptimal circuit. In case of the device first approach, the circuits are made on the silicon substrate using state-of-the-art CMOS processes as usual. After completion of the …

@inproceedings{bib_Theo_2019, AUTHOR = {Mishra, Rishabh Bhooshan and REDDY, NAGIREDDY SESHADRI and Bhattacharjee, Sumana and Hussain, Aftab M. }, TITLE = {Theoretical modeling and numerical simulation of elliptical capacitive pressure microsensor}, BOOKTITLE = {IEEE Conference on Modeling of Systems Circuits and Devices}. YEAR = {2019}}

A capacitive pressure sensor consists of a movable diaphragm which causes change in capacitance for an applied pressure. In order to achieve high sensitivity, a thin diaphragm of large area is employed with a small separation gap. This introduces non-linearity, decreases the dynamic range and increases the size of the sensor. Thus, an optimum sensor design is necessary to balance these trade-offs. This paper presents theoretical modeling and numerical simulations on various performance parameters like diaphragm deflection, change in capacitance, mechanical and capacitive sensitivities and nonlinearity of a clamped and normal mode elliptical capacitive pressure sensor for 0 – 8 kPa operating pressure range. This analysis can form the basis for compact modelling (CM) of circular and elliptical capacitive pressure sensors for simulation with large scale circuits. In all the designs of elliptical and circular …

@inproceedings{bib_Mode_2019, AUTHOR = {REDDY, NAGIREDDY SESHADRI and Mishra, Rishabh Bhooshan and CHARAN, KARNATI KUMAR SAI and Hussain, Aftab M. }, TITLE = {Modelling of Multilayer Perforated Electrodes for Dielectric Elastomer Actuator Applications}, BOOKTITLE = {IEEE Conference on Modeling of Systems Circuits and Devices}. YEAR = {2019}}

A dielectric elastomer actuator (DEA) is a capacitor with an elastomer as dielectric, sandwiched between two complaint electrodes. An electric potential difference applied across the electrodes results in an electric field that creates lateral motion in the device which can be used to perform mechanical work. However, both the dielectric as well as the electrodes needs to be mechanically compliant. In order to achieve high stretchability, carbon nanotube (CNT) based thin films are used as electrodes to maintain conductance even at large mechanical strains. These electrodes are typically fabricated using spray coating or filter transfer method and resemble a perforated electrode under high magnification. Hence, there can be loss of field and stray capacitance when multiple layers of carbon nanotube based electrodes are used. This paper presents theoretical modelling and finite element analysis (FEA) simulations to …

@inproceedings{bib_Meth_2019, AUTHOR = {Hussain, Aftab M. }, TITLE = {Method of producing an electronic device with a graphene device and semiconductor device formed on a common semiconductor substrate}, BOOKTITLE = {United States Patent}. YEAR = {2019}}

ABSTRACT A method for producing an electronic device involves form ing a graphene precursor on a first portion of a common semiconductor substrate, forming a graphene layer on the graphene precursor, and forming a semiconductor device on a second portion of the common semiconductor substrate

@inproceedings{bib_Desi_2019, AUTHOR = {CHARAN, KARNATI KUMAR SAI and REDDY, NAGIREDDY SESHADRI and Mishra, Rishabh Bhooshan and Hussain, Aftab M. }, TITLE = {Design of Micro-heaters Inspired by Space Filling Fractal Curves}, BOOKTITLE = {IEEE Region 10 Symposium}. YEAR = {2019}}

Micro-heating capabilities are important in applications such as thermotherapy, drug delivery, gas sensing and so on. Micro-heaters need to be designed such that they provide uniform temperature across a given surface with minimum metal consumption. In case of Joule heating based micro-heaters, the metal coil design plays an important role in determining its heating characteristics. This paper presents multiple designs of space filling curves that can be used as metal coils in micro-heaters to achieve uniform temperature distribution. We have modelled three types of fractal geometries of different orders - Peano, Hilbert and Moore. In order to compare the performance of these geometries with a typical double spiral heat-pad, we kept a fixed area of 30 mm × 30 mm and input power of 1 W. We have used PDMS (poly-dimethylsiloxane) of thickness 200 μm as a base for the heat-pad and copper is used for the

@inproceedings{bib_Stra_2018, AUTHOR = {Singh, Devendra and Kutbee, Arwa T. and Hussain, Aftab M. and Hussain*, Muhammad M. }, TITLE = {Strain‐Induced Rolled Thin Films for Lightweight Tubular Thermoelectric Generators}, BOOKTITLE = {Advanced Materials Technologies}. YEAR = {2018}}

Thermoelectric generators (TEGs) are interesting energy harvesters of otherwise wasted heat. Here, a polymer‐assisted generic process and its mechanics to obtain sputtered thermoelectric (TE) telluride material‐based 3D tubular structures with unprecedented length (up to seamless 4 cm and further expandable) are shown. This length allows for large temperature differences between the hot and the cold ends, a critical but untapped enabler for high power generation. Compared with a flat slab, better area efficiency is observed for a rolled tube and compared with a solid rod architecture, a rolled tube uses less material (thus making it lightweight and cost effective) and has competitive performance advantage due to a smaller contact area. It is also shown that a tubular architecture thermopile‐based TEG is able to generate up to 5 μW of power (eight pairs of p‐ and n‐type thermopiles) through a temperature …

@inproceedings{bib_Manu_2018, AUTHOR = {Hussain, Muhammad M. and Shaikh, Sohail F. and Sevilla, Galo A. Torres and Nassar, Joanna M. and Hussain, Aftab M. and Hussain, Aftab M. and Bahabry, Rabab R. and Khan, Sherjeel M. and Kutbee, Arwa T. and Rojas1, Jhonathan P. }, TITLE = {Manufacturable Heterogeneous Integration for Flexible CMOS Electronics}, BOOKTITLE = {Device Research Conference}. YEAR = {2018}}

Nearly sixty years back when Jack Kilby built the first integrated circuit (IC), it was also the beginning of today's advanced and matured complementary metal oxide semiconductor (CMOS) technology whose arts and science of miniaturization has enabled Moore's Law to double up the number of devices in a given area in every two years. It has also been possible because CMOS technology has consistently adopted new materials and processes. High performance (data processing speed in computational devices), energy efficiency (for portable devices) and ultra-large-scale-integration (ULSI) density - all these features have been added to every major technology generation in additive manner. As we go forward and embrace Internet of Everything (IoE) where people, process, device and data are going to be seamlessly connected, we may want to ask ourselves a few fundamental questions about the future

@inproceedings{bib_Comp_2018, AUTHOR = {Zhao, Huichan and Hussain, Aftab M. and Duduta, Mihai and Vogt, and Wood, Robert J. and Clarke, David R. }, TITLE = {Compact dielectric elastomer linear actuators}, BOOKTITLE = {Advanced Functional Materials}. YEAR = {2018}}

The design and fabrication of a rolled dielectric elastomer actuator is described and the parametric dependence of the displacement and blocked force on the actuator geometry, elastomer layer thickness, voltage, and number of turns is analyzed. Combinations of different elastomers and carbon nanotube electrodes are investigated and optimized to meet performance characteristics appropriate to tactile display applications, namely operation up to 200 Hz with a combination of a 1 N blocked force and free displacement of 1 mm, all within a volume of less than 1 cm3. Lives in excess of 50 000 cycles have been obtained. Key to meeting these objectives is control of the multilayering fabrication process, the carbon nanotube electrode concentration, the selection of a soft elastomer with low viscous losses, and a proof‐testing procedure for enhancing life cycle reliability.

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