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Shivani Jain Jason Skowronski. Motivation. Powergloves are cool! Can be used for sign-language recognition, video games, wearable computers, ergonomics research, etc A more ergonomic computer interface for mobile users
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Shivani Jain Jason Skowronski
Motivation • Powergloves are cool! • Can be used for sign-language recognition, video games, wearable computers, ergonomics research, etc • A more ergonomic computer interface for mobile users • Currently, gloves don’t measure all the angles or are ridiculously expensive • Immersion Technology’s Cyberglove vs. Nintendo Powerglove
Introduction • The Ultra Power Glove is an input device with a low-power wireless transmitter to transmit the position of the fingers and hand back to the unit using wireless technology. • A video gamer can interact with the game world using his own hands. • Cost of Virtual Reality gloves as opposed to this new technology we developed will allow us to measure accurately the joint positions for only a few dollars in parts per hand.
Problem • Determine finger angle without obstructing the user or constraining movement • Small and low power • Large batteries are heavy and large circuit boards are awkward • Low cost for consumer market
Solution • Glove with sensors mounted on top side of hand • Circuit board with small surface mount components, thin connector wires • Low power wireless • AA battery to power it
Problem Two • Patents on bend sensors prohibit our using common bend sensors in commercial products • Side-to-side rotation cannot be detected using inexpensive sensors
Solution • Translate bend into a measurable perimeter displacement using a mechanical structure
Multidimensional Displacement Sensor • Intensity received by each detector is a function of the relative angle and displacement from the transmitter • Requires minimum 1 detector per dimension • Additional detectors add robustness • LED is a transmitter and 1+ phototransistors are detectors
Direction Vectors (2-axis) vl = pl v1 p1
Transcendental Function • Unfortunately, our derivation lead to a transcendental equation which can only be solved graphically
Approximation • LEDs and phototransistors have narrow-angle lenses with Gaussian profiles • Use this to create a natural weighting function • Slightly overestimates angle • Requires precise spacing
Design • Array of phototransistors detect displacements • PIC microcontroller reads A/D converters on I2C bus, sends data on UART to wireless transceivers • Software on PC normalizes the voltages and calculates the angles, then draws on screen using OpenGL
Components USED • Phototransistors: Measure the distance to a nearby LED, outputs voltage from 0-5V • A/D Converter: Digitizes voltage outputs of phototransistors. Each has 8 analog inputs and presents an I2C interface to the microcontroller. • Microcontroller: A PICmicro Flash microcontroller. It queries A/D converters for data and sends it out on a UART interlink. • Transceiver: Converts UART data from microcontroller to a wireless signal which is received by the PC. • Power: Consists of a battery, a switch, and two voltage regulators to supply the necessary voltages to the components.
Implementation Of the Project SECTION 1 LED’s and phototransistors • Tested all LED’s and phototransistors for functionality. • Soldered braided wires on all of them • Insulated the joint of the wire and the LED/phototransistor. • Glued the completed component to the Glove. • Connected the wires to a SIP connector.
SECTION 2 A/D Convertor and PIC • SIP connector sends inputs to the A/D convertors. • The channel inputs of the A/D convertor took in the signals coming in from the phototransistors and converted it to digital outputs .These were sent to the PIC.
SECTION 3 PCB DESIGN • The printed Circuit Board required almost 2 weeks of work. • We used EASY TRAX to make the PCB. • We ordered surface mount parts to keep our glove as compact as possible. • The top and the bottem layer were used. • An external toggle switch on the PCB.
SECTION 4 INTEGRATIONWe integrated the software and hardware using wireless technology
Other Tests • Test Vcc for relatively small voltage ripple • Test data busses with oscilloscope for proper activity and voltage levels • Verify wireless data output in Hyperterminal, both text and binary • Set debug points in code to verify calculation outputs • Visually inspect finger bend in OpenGL
SUCCESSES • Achieved bending of fingers from bottom to top and side to side • Achieved making a PCB that’s fits on the glove with complete circuitry ,thus making our glove completely mobile. • Professor Carney likes it ! • IT WORKS !!!!!!
Challenges • Perceived mangitude of incoming intensity dependant upon angle causing ripple in metacarpophalangeal joints • Calibration steps records array of intensities at each angle, ran a smoothing function on values, inversed and multiplied by angle
Challenges • Voltage ripple on PCB was much higher than on protoboard despite identical components, removed DC-DC converter on PCB • Resistor bars from parts shop had incorrect resistances yielding PCB unusable • Wireless transciever had a firmware problem causing twitching
FUTURE Our ulimate objective is to make a Wearable Thin Client. • Imagine a screen floating in front of your eye, when you move your hand the cursor moves. • Using your hand in place of a keyboard. • The screen shows your desktop, complete with AIM, eBay, anything else you like. • A mobile wireless computer.
Acknowledgements • Prof. Scott Carney • TA Richard Cantzler (Marty) • ECE parts shop