Design and validation of wearable wireless sensors

Title from PDF of title page, viewed on March 14, 2013Dissertation advisor: W. Daniel Leon-SalasVitaIncludes bibliographic references (p. 102-[113])Thesis (Ph.D.)--School of Computing and Engineering. University of Missouri--Kansas City, 2012Recent years have seen an increase in research and development efforts towards wearable and implantable health monitoring systems. Such systems are needed to provide real-time information about patients to physicians, care-givers, emergency personnel and relatives. The challenge lies in their designing as they need to satisfy a variety of criteria and constraints. These include small weight and size, low power consumption, easy to use, and should be aesthetically pleasing. Advances in semiconductor fabrication have made commercially available highly integrated systems-on-chip (SOC) which are being exploited to develop such systems. Use of these SOCs reduces cost and development time. This dissertation presents system prototypes that can capture human body motion, measure strain on bones and perform electromyography (EMG). Design of these systems is centered on ultra-low power microcontrollers and other required circuit components. We present in detail their design, functionality and compare our results with present solutions.Introduction -- A wearable motion tracker -- Bone strain measuring telemetry units -- Wireless surface electromyography (EMG) sensor -- Conclusion

Motion Tracking for Smart Home Care

Computational Infrastructure and Informatics Poster SessionHuman body motion capture has a wide range of applications and is being extensively investigated. Areas of application include virtual and augmented reality, biomechanics, sign language translation, gait analysis and graphics in movies and video games. The goal of this work is to develop an electronic device to translate arms motion and hand gestures into computer commands for smart home applications. This device is expected to improve the communication and lifestyle of elderly and disable people. We envision a device that is wearable, seamless and easy to use. Current state-of-the-art body motion capture employs high-speed and high-resolution cameras. Although this method is accurate and useful in laboratory settings, it requires the user to be inside the field of view of the cameras, a condition that is not always feasible during everyday activities. Instead, our approach relies on small sensors nodes that are worn on the wrists and around the waist. Inertial sensors such as accelerometers and gyroscopes have been employed before to develop wearable motion-tracking sensors due to their small size. However, they suffer from drift which causes the position estimations to have large errors. Ultrasonic sensors have also been employed to track motion. Although more accurate, ultrasonic sensors are affected by intermittent signal blockage produced by the body. Our approach is to combine these two sensing modalities in a way that the position estimation error is reduced. To that end, the outputs of the inertial and ultrasonic sensors are fused using a Kalman filter. The sensor nodes implement a multilateration algorithm that calculates the position of body-mounted sensors by measuring the time of travel of ultrasound bursts traveling between the sensor nodes. An electronic board for the sensor nodes have been designed, fabricated and programmed. The board measures 3.2 cm x 4.8 cm and includes a low-power microcontroller, a radio unit, a three-axis accelerometer, a two-axis gyroscope, an ultrasonic transmitter and an ultrasonic receiver. Our ongoing activities include the development of a 3D virtual simulation of a smart home. In the virtual smart home, various electronic devices such as computers, cell phones and household appliances like microwaves and televisions are networked for ubiquitous services. The wearable sensors capture the limb movements and relay this data to a central controller where it is interpreted to adjust the home environment. The sensors can also be used for emergency care by detecting any abnormal movements. Our approach will significantly improve current motion capture systems that are too cumbersome to wear or require the subject to be confined to a controlled environment or within the view range of the camera. Besides their use in smart home scenarios, the proposed wearable motion-tracking sensors can be used in biomechanic studies, virtual reality and interactive games

Development of a Telemetry Unit for Wireless Monitoring of Bone Strain

Computational Infrastructure and Informatics Poster SessionA telemetry unit designed to monitor strain in bones is presented. This unit allows studying the relationship between bone load and bone mass in scenarios that were not possible with current setup. The current measuring setup employs a bench top load instrument and a data acquisition unit to read the output of strain gage sensors attached to the ulna of a mouse. Although precise, this setup is bulky and requires complete immobilization of the mouse. The telemetry unit developed by the authors replaces the data acquisition unit in the current setup and is able to wirelessly transmit the readings of the strain gage to a remote computer. The telemetry unit makes possible the collection of bone strain data in scenarios where the mouse is free to move or while performing fatigue-inducing exercises. The unit has been designed around an ultra low-power microcontroller (MSP430). The microcontroller makes the design highly flexible and programmable. The telemetry unit also includes a high-performance instrumentation amplifier to amplify the strain gage output. The gain and offset of the amplifier are digitally set by the microcontroller eliminating the use of manual potentiometers. The board has an expansion connector that allows up to 16 additional strain gages to be connected to the unit and incorporates a low-power radio transceiver operating in the 2.4 GHz ISM band. The data transmitted by the unit is received by a base station connected to a computer via a USB cable. The telemetry unit has been tested in a lab setting and is able to transmit the strain data at distances greater than 20 m while consuming less than 30 mW of power. This low power consumption allows the unit to be powered by a micro-battery weighting less than 3 grams. The telemetry unit can be used in other biomedical applications such as in the monitoring of orthopedic implants and can be easily configured to use other type of sensors

An embedded multichannel telemetry unit for bone strain monitoring

Abstract An embedded telemetry unit for bone strain monitoring is presented. The telemetry unit is designed using commercially available components to lower design time and manufacturing costs. The unit can read up to eight strain gauges and measures 2.4 cm × 1.3 cm × 0.7 cm. The unit is powered from a small Li-polymer battery that can be recharged wirelessly through tissue, making it suitable for implanted applications. The average current consumption of the telemetry unit is 1.9 mA while transmitting at a rate of 75 kps and at a sampling rate of 20 Hz. The telemetry unit also features a power-down mode to minimize its power consumption when it is not in use. The telemetry unit operates in the 915-MHz ISM radio band. The unit was tested in an ex vivo setting with an ulna bone from a mouse and in a simulated in vivo setting with a phantom tissue. Bone strain data collected ex vivo shows that the telemetry unit can measure strain with an accuracy comparable to a more expensive benchtop data acquisition system.Peer Reviewe

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Over the years, several forms of energy resources have been used for a variety of purposes; however, the over use of energy supplies has resulted in a variety of problems. Renewable energy sources are an excellent approach for addressing these challenges. In recent years, it has become possible to modify photoelectrochemical cells with titanium dioxide, cadmium sulfide, and graphitic nitride to create clean hydrogen. It has been discovered that the doping method enhances the photocatalytic activity of the catalyst. Metal-oxide nanoparticles are common dopants; one example of this is iron-doped TiO2, which exhibits remarkable quantum efficiency due to the presence of iron. Nanomaterials with excellent crystallinity, three-dimensional structure, and tiny size are needed for obtaining high photocatalytic efficiency. The focus of the current research is on clean fuel production (hydrogen synthesis) using a doped titanium dioxide photocatalyst. In addition to clean fuel generation, attention is being paid to the development of titanium dioxide doping technologies and the doping of titanium dioxide. Experimental manufacturing approaches have been investigated to achieve this goal. Both theoretical (computational) and experimental methodologies have been discussed that aid in reducing band gap of pure Anatase TiO2 and may help in achieving better photocatalytic water splitting (PWS) for hydrogen production