Rahul Bhattacharyya

Low-Cost, Ubiquitous RFID-Tag-Antenna-Based Sensing

Radio-frequency identification (RFID) has been well established as an effective technology for track and trace applications. In this paper, we go beyond the ID in RFID, and discuss the potential for RFID tags to be used as low-cost sensors by mapping a change in some physical parameter of interest to a controlled change in RFID tag antenna electrical properties. We will also show that it is possible to design the tag antenna to suffer a permanent change in case of violation of a critical threshold in the parameter of interest thereby creating a low-cost threshold sensing mechanism. This can be achieved by inducing controlled changes to the tag antenna geometry parameters or to the antenna boundary conditions, in effect creating a nonelectric memory to monitor state. After identifying the application space for which this class of sensing is well suited, we present details into the design and testing of three different kinds of sensors based on this sensing paradigm. We demonstrate how we use this concept to sense displacements, temperature thresholds, and fluid levels. We will show that RFID-tag-antenna-based sensing has the potential to revolutionize application domains in which there is a need for low-cost, long-lasting, ubiquitous sensors.

Towards tag antenna based sensing - An RFID displacement sensor

Displacements can be used as indicators of structural health and are measured by commercially available sensors that need to be accurate and cost effective. In this paper, we examine a technique to utilize a UHF RFID tag antenna as a displacement sensor by mapping structural deformation to a change in RFID tag characteristics. We evaluate how changes in two different parameters, a) tag backscatter power and b) minimum reader transmit power required for RFID chip activation, can be mapped to structural deformation. The theoretical principles of sensor development are first discussed followed by a presentation of the results of experimentation. It is demonstrated that the sensor is sensitive to displacements for a dynamic range of 40 mm.

RFID tag antenna based temperature sensing in the frequency domain

The efficiency of cold supply chain operations can be improved with pervasive temperature sensing. In this paper, we investigate the design of a low-cost, single-use RFID based temperature threshold sensor that is capable of relating the violation of a temperature threshold to a shift in the optimal operating frequency at which the tag antenna is well matched to the tag IC. This shift is detectable by commercial UHF RFID readers operating in the 902–928 MHz frequency band. We will illustrate how state change information is preserved using a nonelectric memory mechanism that works even in the absence of reader transmitted power. We demonstrate that the sensor works reliably for a read distance of over 3 m and in noisy environments.

RFID tag antenna based sensing: Does your beverage glass need a refill?

Liquid level detection in customer beverage glasses and liquor bottles in the service industry is important for maintaining quality of service and good approval ratings. Current sensing approaches rely either on visual inspection or expensive sensor electronics to detect liquid levels. In this study, we investigate how the paradigm of RFID tag antenna based sensing can be used as a low-cost alternative in the service industry, to detect the volume of liquid in a beverage glass by mapping a change in RSSI power measurements from RFID tags to the level of liquid in the glass. We demonstrate that this sensing technique when deployed in a real restaurant-like setting can be used to accurately predict the state of the glass over 80% of the time, and thus has good potential as a low-cost sensing methodology for applications in the restaurant industry.

RFID Tag Antenna-Based Sensing for Pervasive Surface Crack Detection

We introduce the concept of using an RFID tags antenna to sense surface cracks. Our contribution is two fold. First, we present the design of an inductively coupled loop antenna that can be used as a crack detector. Second, we propose the development of a 2-D grid of tags to improve spatial coverage and discuss how it can be used to monitor typical crack patterns in civil infrastructure. We demonstrate that the technique works reliably over a read distance of 1 m and in different types of environments. Potential engineering extensions and future research directions are also discussed.

Towards chipless RFID-based sensing for pervasive surface crack detection

We present Surface Crack Antenna Reflectometric Sensing or SCARS: a chipless RFID sensor that enables pervasive, wireless surface crack detection in structural materials. We outline the sensor design and demonstrate how crack length and orientation can be related to the backscatter signal signature of the SCARS sensor. In doing so, design techniques that improve sensor sensitivity and signal fidelity are presented. Proof of concept is then demonstrated via numerical simulation and the implementation of a laboratory prototype. Finally, an envisioned pervasive health monitoring and data extraction strategy using these sensors is also discussed.

RFID tag antenna based temperature sensing using shape memory polymer actuation

Ubiquitous temperature monitoring is important to boost visibility in applications such as cold supply chain management. Current sensors monitor and log a time history of temperature data, but their cost limits the scale of deployment. In this paper, we propose an ultra-low cost temperature threshold sensor using the UHF RFID tag antenna as a sensing mechanism. Permanent changes are induced in the tag antenna electrical properties upon violation of a temperature threshold. This manifests itself in a change in backscatter power detected at the reader. We demonstrate how these changes are effected via shape memory polymer actuation. Experiments demonstrate that cheap, reliable temperature threshold sensors can be developed which are independent of the material of deployment, orientation of the sensor, which have a read range of over 3 m and which have a customizable critical temperature threshold.

Beyond the ID in RFID

Wireless sensing devices are increasingly utilized to gather information about the environment of deployment. In this chapter, we analyze the requirements of an idealized wireless sensing node and discuss how effective battery powered wireless sensors are, in addressing these requirements. We also evaluate the advantages and shortcomings of alternative passive wireless sensing approaches emphasizing an emerging paradigm of RFID tag antenna-based sensing that offers great potential for the development of ultra low cost, long-lasting wireless sensors.

Guest Editorial Special Section on Advances and Applications of Internet of Things for Smart Automated Systems

In 1999, Kevin Ashton envisioned a novel paradigm named Internet of Things (IoT), in which all things could see, hear, and smell the world for themselves, and interact with each other and cooperate with their neighbors to reach some common desired goals. In the following years, the IoT ideas started to spread rapidly due to the technology advancements in the fields of microelectromechanical systems and most recently, nanoelectromechanical systems, computers, and wireless communications, resulting in autonomous everyday thing augmented with sensing/actuation, storage, processing, and network capabilities. Their new applications emerged daily from smart homes to smart cities, from automobiles to high-speed trains, from new-born care devices to patient operating rooms and entire hospitals, and from manufacturing factories to agricultural food plants. IoT is one of the fastest growing technical areas across almost all engineering disciplines and touches almost all verticals of the World Economy. It represents major investments in commercial and government initiatives. We expect to have over 40% Compound Annual Growth Rate year over year in the commercial marketplace and to dominate “traffic” on the Internet within the next decade.

Smartphone-Based Wheel Imbalance Detection

Onboard sensors in smartphones present new opportunities for vehicular sensing. In this paper, we explore a novel application of fault detection in wheels, tires and related suspension components in vehicles. We present a technique for in-situ wheel imbalance detection using accelerometer data obtained from a smartphone mounted on the dashboard of a vehicle having balanced and imbalanced wheel conditions. The lack of observable distinguishing features in a Fourier Transform (FT) of the accelerometer data necessitates the use of supervised machine learning techniques for imbalance detection. We demonstrate that a classification tree model built using Fourier feature data achieves 79% classification accuracy on test data. We further demonstrate that a Principal Component Analysis (PCA) transformation of the Fourier features helps uncover a unique observable excitation frequency for imbalance detection. We show that a classification tree model trained on randomized PCA features achieves greater than 90% accuracy on test data. Results demonstrate that the presence or absence of wheel imbalance can be accurately detected on at least two vehicles of different make and model. Sensitivity of the technique to different road and traffic conditions is examined. Future research directions are also discussed.Copyright