1 / 26

Eye Controlled Typing

Group 37 Xiaoyu Ma, Hung-Yuan Wu ECE 445 Senior Design April 27, 2006. Eye Controlled Typing. Introduction. Provides a way to communicate for the paralyzed Takes advantage of eye movements – the only method of control. Objectives. EOG electrodes to sense eye movement

read
Download Presentation

Eye Controlled Typing

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Group 37 Xiaoyu Ma, Hung-Yuan Wu ECE 445 Senior Design April 27, 2006 Eye Controlled Typing

  2. Introduction Provides a way to communicate for the paralyzed Takes advantage of eye movements – the only method of control

  3. Objectives EOG electrodes to sense eye movement EMG signals detects for blinking Non-standard keyboard layout for easier typing Text display window Text-to-Speech feature Low cost

  4. System Overview Hardware High gain amplifier, filter, summing amplifier, calibration indicator Buffer, power supply Software PIC programming, RS232 communication User interface

  5. Hardware Schematic

  6. Hardware circuit on protoboard LED indicator Instrumentation Amplifier Summing Amplifier Buffer

  7. Hardware Description Amplifier Provides gain of 1000 Filter Blocks noise greater than 32Hz Summing amplifier Shifts signal to valid input range of PIC Calibration indicator LED to indicate calibration

  8. Hardware Additions Buffer Circuit Provides lower output impedance +/- 5V power supply Input from 9V battery Portability

  9. Amplifier Testing • Check for gain of 1000 Input sine wave of 1mVPP Outputs sine wave of 1VPP

  10. Amplifier Testing • Check for flat frequency response

  11. Summing Amplifier • Controlled by potentiometer • Able to add +5V to -5V to signal

  12. Electrode output Response after looking up, right, down, and left.

  13. Power Supply Takes input from 9V battery Outputs +5V, GND, and -5V with maximum current of 1A Supplies all amplifiers, PIC, MAX232 *Circuit taken from ECE 445 Course website

  14. Power Supply Ripple of 21.3mV at +5V output Average output of 5.0645V Output level fairly constant and stable

  15. Software

  16. Software Description PIC Microcontroller Performs 10 bit ADC on vertical and horizontal input voltage Interprets eye movement based on voltage range Output through RS232 communication User Interface Read input through serial port Update text window and keypad Text to Speech

  17. PIC Microcontroller j Fox F1100 20Mhz Oscillator PIC16F877A MAX232

  18. PIC Microcontroller H\V 0 – 1 V 1 – 2 V 2 – 3 V > 3 V 0 – 1 V Down Left Left Up Left Blink 1 – 2 V Down Center Up Blink > 2 V Down Right Right Up Right Blink

  19. User Interface

  20. User Interface Programmed in Visual Basics 6.0 Non-conventional keyboard layout, similar to those on a cell phone Communicates with PIC through RS232 Low system requirements

  21. Text to Speech

  22. Problems and Challenges Hardware Low signal transfer into PIC Signal drift due to sensitivity of electrodes Software Interpreting diagonal movements Detecting blink Transition values Text to Speech

  23. Results Works but not as reliable as planned Can't be used for long periods of time User must remain fairly still during use Project parts cost of $42.14 with each battery lasting about 20 hours

  24. Sample Screenshots

  25. Improvements Signal processing Uses differences in voltage average to detect eye movement Solves drifting in signal Goggle Ties wires to electrodes together More portable Re-useable Word Prediction Faster typing User interface on hand held devices More portable

  26. Acknowledgements Dwayne Hagerman for guidance and suggestions Professor Ray Fish for supplying plenty of electrodes ECE Parts Shop for most of circuit devices Analog Devices and Microchip for providing free samples

More Related