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Wearable Sensors. Final Presentation 05-10-04. Problem Background. MIT Research Affective Wearable Computers. Inferred Transmission (short range) Bulky Design, hard to wear 20 Samples per second. Goals and Objectives. To create a wearable device that reads
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Wearable Sensors Final Presentation 05-10-04
Problem Background MIT Research Affective Wearable Computers • Inferred Transmission (short range) • Bulky Design, hard to wear • 20 Samples per second
Goals and Objectives To create a wearable device that reads temperature, skin conductance, and blood volume pulse and transmits data wirelessly to a computer, where it will be displayed in real time.
Expected Product Layout Blood Volume Pulse (BVP) Lapaic Wireless Transmitter Temperature Galvanic Skin Conductor Transmission Board Team Sensors Team Lapaic Wireless Receiver GUI Microcontroller Software Team
Team Overview • Sensors Team • Phillip Hay • Rosy Logioia • Gouri Shintri • Transmission / Microcontroller Board Team • Christina Hernandez • Clayton Smith • Adam Stevenson • Software Team • Daniel Bishop • Josh Handley
Sensors BVP Detection and Filtering BVP Subtraction and Offsetting Temperature Galvanic Skin Conductance
Sensors (Design Specs) • Strengths • Compact • Wearable • Low power • Weaknesses • Poor quality board and parts • Sensitive signals • Inconsistent signals (BVP)
Transmission Board Layout PCB Layout Schematic
Transmission Board (Design Specs) • Strengths • Size (1.8” square) • Potential wireless transceiver and microcontroller on same board • Weaknesses • Wasted space where Chipcon was originally soldered onto board • Separate transceiver / microcontroller boards
Software Overview Divided into 2 programs that run concurrently: • Cygnal microcontroller • PC: The Wearable Sensor Display Utility (WeaSeL) • Connected through a USB Connection
Microcontroller Software Microcontroller Code: • Interrupt Driven • Polls data from A/D converter every X seconds. • Transmits it to PC via USB using a custom packet protocol.
MCU to Computer USB Connection • Used to connect the microcontroller to the computer • The device uses a simple FIFO interface • The high data speed rate coupled with a ~64k byte buffer on the computer, allows for our sensor technology to quickly send large amounts of data points to the computer for processing • The device is powered by the computer through the USB connection and therefore no additional power constraints are added to the project From: http://www.dlpdesign.com/usb/
Microcontroller / USB Connection(Design Specs) • Strengths • C-based IDE • Interrupt Driven • No wasted clock cycles • Easier to maintain code • USB • High Data Rate • Built in Buffering System • Easy to integrate w/ .NET C# • 1.1 Compliant • Weaknesses • Microcontroller clock somewhat erratic • ADC has some spill over
WeaSeL • Reads data from the USB port • “Real time” display of sensor readings, similar to oscilloscope • Can save readings to a file for future comparison
WeaSeL(Design Specs) • Strengths • Easy to visualize changes in data • User-friendly • Weaknesses • USB buffering may cause WeaSeL to lag or stall
Final Product Layout Blood Volume Pulse (BVP) GUI Temperature Microcontroller Galvanic Skin Conductor Lapaic Wireless Transmitter Software Team Sensors Team Transmission / Microcontroller Board Team Lapaic Wireless Receiver
Project Status • Due to lack of time and equipment, our team was not able to complete wireless transmission of data. • The transmission code is currently being reviewed by Laipac Corporation.
Project Integration Sensor board hooked up to user and microcontroller Microcontroller on evaluation board hooked up to USB
Team Management Issues • Schedule Conflicts • Areas of Expertise • Time Management (other classes, work, graduation, etc) Resolving the Issues • Communication • Division of Work • Weekly Team Meetings
Engineering Standards and Safety • Easy to produce because of availability of parts • Product is for medical purposes • Product is powered by batteries at low voltage • Batteries must be disposed of properly to prevent environmental harm
Project Sponsors This project was completed with the help of the Computer Science Department at Texas A&M University, especially Dr. Ricardo Gutierrez, Dr. Steve Liu, and Dr. Cote from the Biomedical Engineering Department. The project was financially sponsored by Applied Materials and the National Science Foundation.