1. Ocular Prosthesis Team Members: Adam Lee, EE Faculty Advisors:
May0013
Team Members:
Adam Lee, EE
Juhaidi Abd-Hamid, EE
Ryan Littler, CprE
Brian Mestan, CprE
Faculty Advisors:
Dr. Ralph Patterson III
Dr. Charles Wright

2. Presentation Overview
General Background
End-product Description
Technical Solution
Electrodes, Filter/Amplifier Circuit
Microcontroller Design
Wheelchair Interface
Milestones
Budget
Conclusion
Questions

3. General Background
Severely disabled are unable to perform everyday tasks due to loss of muscle control.
In many cases, basic eye movement is retained.
Eye motion can be detected allowing the disabled access to a variety of devices.
Previous work in this field:
Utah Arm, Eye mouse, ISU wheelchair
Our project focuses on using eye movement to control a wheelchair.

4. End-Product Description
Interface to control an electric wheelchair using eye movement rather than joystick.
Features:
Controlled by simple eye movements and combinations
Safety features
Full 360-degree movement
Compact to fit on wheelchair
Shock and temperature resistant
Inexpensive

5. Electrooculogram Signals
Biological phenomenon (like ECG, EEG)
Small positive charge at front of the eye
Micropotential created by eye movement (50–100uV)
Electrodes can detect this potential in regions around eyes

6. Technical Description

7. Filter/Amplifier Design
Function:
Convert micropotentials into useable input for microcontroller.

8. Filter/Amplifier Design
Problem/Solution:
Research to determine best placement and type of electrodes.
Small signal levels(50-100uV) – Amplification.
Noisy signals – Filtering.

9. Filter/Amplifier Design
Implementation:
Instrumentation Amplifier
High-Pass Filter
Amplification
Offset Adjust
Voltage Converter
Low-Pass Filter

10. Microcontroller Design
Functions:
Decode eye movements into corresponding wheelchair movements.
Provide emergency stop capability and other safety features.
Distinguish “real commands” from noise and errant signals.

11. Microcontroller Design
Problem/Solution:

12. Microcontroller Design
Implementation:
MCHC11A1FN
8bit – 8 channel A/D
256byte internal RAM, 32KB battery-protected static RAM
2MHz system clock
Interactive C compiler
Development on MIT Handy Board

13. Wheelchair Interface Function:
Emulate joystick of wheelchair using signals from microcontroller.

14. Wheelchair Interface Problem/Solution:
Cannot use the microcontroller output directly to control wheelchair.
Circuit is needed to convert microcontroller outputs into signals that are typically seen from the joystick.

15. Wheelchair Interface Implementation: Wheelchair based off 6V signal.
To move chair – 6V signal is raised or lowered by summing with signal from microcontroller.
Op-amps used to implement summing circuit.
Circuit is tuneable to select base speed and precision of movement.

16. Milestones Project success measured by completion of:
Research on placement/type of electrode for system (100%)
Design of amplifier and filter electronics (70%)
Design of microcontroller system (10%)
Design of interfacing circuitry (70%)
Subcomponent testing: amplifier/filter, microcontroller program, and interface circuitry (20%)
System level testing (0%)

17. Financial Budget

18. Conclusion Meaningful project with important solution.
Proof of concept that could open up a wide-range of other devices to disabled.
Inexpensive compared to current IR solution.
Areas of Future Work:
Universal interface
Infrared voltage detection
Remote control
Serial/USB ports

19. Questions ?