Smart Indoor Positioning/Location and Navigation: A Lightweight Approach

In this paper a new location indoor system is presented, which shows the position and orientation of the user in closed environments, as well as the optimal route to his destination through location tags. This system is called Labelee, and it makes easier the interaction between users and devices through QR code scanning or by NFC tag reading, because this technology is increasingly common in the latest smartphones. With this system, users could locate themselves into an enclosure with less interaction

LPS Auto-Calibration Algorithm with Predetermination of Optimal Zones

Accurate coordinates for active beacons placed in the environment are required in Local Positioning Systems (LPS). These coordinates and the distances (or differences of distances) measured between the beacons and the mobile node to be localized are inputs to most trilateration algorithms. As a first approximation, such coordinates are obtained by means of manual measurements (a time-consuming and non-flexible method), or by using a calibration algorithm (i.e., automatic determination of beacon coordinates from ad hoc measurements). This paper presents a method to calibrate the beacons’ positions in a LPS using a mobile receiver. The method has been developed for both, spherical and hyperbolic trilateration. The location of only three test points must be known a priori, while the position of the other test points can be unknown. Furthermore, the paper describes a procedure to estimate the optimal positions, or approximate areas in the coverage zone, where the test-points necessary to calibrate the ultrasonic LPS should be placed. Simulation and experimental results show the improvement achieved when these optimal test-points are used instead of randomly selected ones

CARE: COVID-19 Abatement Return to Education

The COVID-19 pandemic poses new challenges in many aspects of life and society. Being that the prime ethical responsibility of engineers is to keep people safe, our sponsor, John Nielsen, asked us to develop a solution that addresses a current or anticipated need related to the ongoing COVID- 19 pandemic. We entered a needs-finding phase to search for problems caused by COVID-19 that people want or need to be solved. We identified K-12 education as an area that has undergone drastic changes due to the pandemic. After conducting interviews with educators, we found that K-12 teachers need a way to return to the classroom safely without relying on the decisions of their students. Our project addresses the following problem statement: K-12 teachers need a way to feel safe during the COVID-19 pandemic so that they can return to in-person teaching. Based on our interviews, guaranteeing the enforcement of safety protocols makes K-12 teachers feel safe. We decided to build a toolbox of devices to help teachers enforce sanitation and personal protective equipment (PPE) protocols. The sanitation device is an automatic disinfecting spray placed above high touch surfaces, like doorknobs, that automatically sanitizes the desired surfaces after any individual touches it. The PPE device is a face shield with a microphone and speaker that enables teachers to overcome the tiring and difficult task of speaking over a face covering. For our toolbox prototype, we purchased or 3D printed all the components. Our automatic disinfecting spray prototype uses a motor and cam controlled by a microcontroller to actuate a nozzle that sprays liquid sanitizer. The system can attach to doors or other flat surfaces via an adhesive mount and adjustable arm. The face shield prototype consists of a microphone and speaker attached to a shoulder-mounted face shield. As we manufactured and assembled our toolbox, we tested individual components and subassemblies to ensure that they operated as expected and would properly integrate into each system. In addition, we performed usability testing for the completed components with teachers and friends. The responses from our user testing indicated the face shield was easy to operate and effective. While the disinfecting spray could use improvements in usability, it functioned as expected. Based on feedback from our usability testing, we recommend reducing the bulkiness of the overall disinfecting spray system and improving the adjustability of the mounting. We also recommend further testing in a wider range of environments to ensure all use cases of the toolbox are covered. We need further nozzle and adhesive testing for the disinfecting spray as the current nozzle tends to leak and the adhesive leaves behind a sticky residue when removed. Moving forward, to reduce the toolbox cost, we recommend pursuing mass manufacturing including purchasing components in bulk and injection molding instead of 3D printing. We also recommend replacing breadboard and wire circuits with custom PCBs for cleaner packaging and less unnecessary electronics parts. Overall, the face shield and automatic disinfecting spray toolbox allows teachers to focus their attention on what really matters, teaching, while maintaining a safe environment

Treadmill User Centering

The goal of team CENTREAD was to design a device to allow a person with a visual disability to run efficiently and effectively on a treadmill without fear of falling off or injuring themselves. The customer wished for the device to be small, lightweight, and have an easy, autonomous setup, while providing feedback to the user wirelessly for them to correct their own movement. The ultimate goal of the device is to allow the user to be comfortable, safe, and free while using it in order to ensure they have the best running experience. The device utilizes ultrasonic sensors in housings to detect distances of objects using sound wave pulses. These sensors send signals out and detect the amount of time it takes for the signal to return to the same place, taking that time and converting it into a distance. These distances are sent directly into a microcontroller, where the microcontroller collects and analyzes the data. While analyzing the data, the microcontroller looks for data points that are within the boundaries set as not safe zones. These data points are then assigned a value and are sent over to a wireless transmitter to communicate with its sister receiver. The receiver detects a signal sent from the relative transmitter and sends the signal to another microcontroller to be processed. This process takes the value sent from the transmitter and assigns that value to a pin to activate a voltage to. This pin contains a small eccentric weighted motor that vibrates when a voltage is applied. This vibration is then interpreted by the user to move in the opposite direction of the vibration, correcting their location. This device utilizes two housings, one along the length axis of the treadmill belt and one along the width axis of the treadmill belt. These boxes interpret backwards distance from the front edge of the belt and left and right distance from the inside face of the right treadmill arm, respectively. These housings each contain their own microcontroller and transmitter that communicate with the receiver. The receiver is contained with a belt that the user wears, and collects signals from both housings. The microcontroller interprets these signals and applies a voltage to the respective motor. These motors are located on the left, right, and back of the belt and are there to correct the user to the right, left, and forwards respectively. This feedback system ultimately serves the purpose for solving the users problem and is an effective way of helping them get back to running confidently and safely again

Auto-localization algorithm for local positioning systems

This paper studies the problem of determining the position of beacon nodes in Local Positioning Systems (LPSs), for which there are no inter-beacon distance measurements available and neither the mobile node nor any of the stationary nodes have positioning or odometry information. The common solution is implemented using a mobile node capable of measuring its distance to the stationary beacon nodes within a sensing radius. Many authors have implemented heuristic methods based on optimization algorithms to solve the problem. However, such methods require a good initial estimation of the node positions in order to find the correct solution. In this paper we present a new method to calculate the inter-beacon distances, and hence the beacons positions, based in the linearization of the trilateration equations into a closed-form solution which does not require any approximate initial estimation. The simulations and field evaluations show a good estimation of the beacon node positions

Chipless RFID sensor systems for structural health monitoring

Ph. D. ThesisDefects in metallic structures such as crack and corrosion are major sources of catastrophic failures, and thus monitoring them is a crucial issue. As periodic inspection using the nondestructive testing and evaluation (NDT&E) techniques is slow, costly, limited in range, and cumbersome, novel methods for in-situ structural health monitoring (SHM) are required. Chipless radio frequency identification (RFID) is an emerging and attractive technology to implement the internet of things (IoT) based SHM. Chipless RFID sensors are not only wireless, passive, and low-cost as the chipped RFID counterpart, but also printable, durable, and allow for multi-parameter sensing. This thesis proposes the design and development of chipless RFID sensor systems for SHM, particularly for defect detection and characterization in metallic structures. Through simulation studies and experimental validations, novel metal-mountable chipless RFID sensors are demonstrated with different reader configurations and methods for feature extraction, selection, and fusion. The first contribution of this thesis is the design of a chipless RFID sensor for crack detection and characterization based on the circular microstrip patch antenna (CMPA). The sensor provides a 4-bit ID and a capability of indicating crack width and orientation simultaneously using the resonance frequency shift. The second contribution is a chipless RFID sensor designed based on the frequency selective surface (FSS) and feature fusion for corrosion characterization. The FSS-based sensor generates multiple resonance frequency features that can reveal corrosion progression, while feature fusion is applied to enhance the sensitivity and reliability of the sensor. The third contribution deals with robust detection and characterization of crack and corrosion in a realistic environment using a portable reader. A multi-resonance chipless RFID sensor is proposed along with the implementation of a portable reader using an ultra-wideband (UWB) radar module. Feature extraction and selection using principal component analysis (PCA) is employed for multi-parameter evaluation. Overall, chipless RFID sensors are small, low-profile, and can be used to quantify and characterize surface crack and corrosion undercoating. Furthermore, the multi-resonance characteristics of chipless RFID sensors are useful for integrating ID encoding and sensing functionalities, enhancing the sensor performance, as well as for performing multi-parameter analysis of defects. The demonstrated system using a portable reader shows the capability of defects characterization from a 15-cm distance. Hence, chipless RFID sensor systems have great potential to be an alternative sensing method for in-situ SHM.Indonesia Endowment Fund for Education (LPDP

Distance Estimation Between Transceivers Over Short Distances

Three methods for determining distances between a user and a fixed coordinate system are considered. One system is based on 802.11g packet communications, another on HF radio carrier frequency interference, and the final system on a signal transmitted over a radio channel. Emphasis is placed on the use of these systems in indoor, building-sized environments. Tests are performed to examine the effectivness and potential of these methods. None of the suggested methods are determined to be usable. Reasons for their failure are examined

NASA Tech Briefs, December 1994

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