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Home | DTI | 2005–06 funded proposals | R. Rajamani, William Robbins

Initiatives in Digital Technology: 2005–06 Funded Proposals

R. Rajamani, William Robbins

Wireless Sensors and Estimation Algorithms for Interface Pressure Measurement in Clinical Plaster Cast Applications: Compartment Syndrome is a very serious complication that occurs in a cast due to swelling and can cause ischemia, necrosis and serious nerve injuries.

Compartment Syndrome is a very serious complication that occurs in a cast due to swelling and can cause ischemia, necrosis and serious nerve injuries. It can be prevented by monitoring the skin surface pressure inside the cast. This project focuses on the development of small-sized battery-free wireless interface pressure sensors to perform this monitoring function. Several fundamental challenges will have to be addressed in order to achieve the desired sensor system operation. These challenges include 1) achieving adequate telemetry distance (up to 10 cm), 2) achieving accurate measurement in spite of imprecise alignment and unknown distances between interrogator unit and the sensors, and 3) developing an inexpensive interrogator unit. This project proposes a novel antenna and a novel multi-frequency continuous inductive coupling based approach to wireless sensing to achieve the 10 cm telemetry distance. The use of multiple frequency excitation and the development of novel adaptive algorithms for robust estimation is proposed for achieving accurate measurement in spite of imprecise alignment and unknown distances between the interrogator and the sensors. The cost of the interrogator will be kept low by the use of inexpensive analog electronics and a low-cost microprocessor for implementing the adaptive algorithms. The proposed wireless sensors also have a significant number of other biomedical applications, including their use to measure footprint pressures in diabetic patients with neuropathy, prevention of pressure sores in patients with spinal cord injuries, prevention of bed sores in patients confined to beds or wheelchairs and interface pressure measurement for prosthesis design. The work plan for the project includes design and fabrication of the small-sized pressure sensors, evaluation of the multi-frequency adaptive algorithm and experimental evaluation of performance of the wireless sensors inside a simulated cast that includes a blood pressure cuff and standard sensors.