Problem Overview
Quadriplegics do not have control of their extremities, which limits their ability to perform mundane activities such as using a computer. A patient who does not have full control of their hands will experience difficulty when trying to maneuver a mouse to instruct the cursor to move up, down, left, right, or even click on a computer screen. Quadriplegics may have trouble communicating with others and may need various sources of help to lead a manageable life. These sources include physical therapists, occupational therapists, speech pathologists, and attendants. [1]
Pre-Existing Solutions
In the realm of alternate mouse interfaces, there are other attempts to provide a solution such that disabled people can use computers. For example, a study at Stanford University created a software called EyePoint, which is a non-invasive technique that tracks the movement of the eyes using a webcam. The main problem with this technique for mouse interfacing is the need for specialized hardware in order to run this kind of software. Also, this eye tracking device still requires the user to click on a number pad which acts as the “clicking” function on the mouse. This defeats the point of creating an interface for those who do not have access to motor control in their limbs [2]. The video below allows for more insight on the software and includes a demonstration of the EyePoint software.
In addition, there are current studies where disabled patients are using EEG signals in order to control a cursor on a screen. However, the main problem with this alternative is the responsiveness of the cursor once the EEG signals have been captured.
The goal of the design is to create a device that will allow quadriplegics to control the cursor on a computer screen using EOG signals. This will allow the patients to navigate a computer without the use of their hands. This particular design is different than previous attempts because it will depend solely on the motion of EOG muscles and will be accessible to any operating system since the electronic properties of the mouse will not be altered. Also, the approach is noninvasive because the electrodes will simply be placed on the patient’s face. This allows more flexibility for the patient while still being easy to use.
In order to use the electrodes, multiple tests need to be conducted. The appropriate placement of the electrodes around the eyes and on the jaw will allow for the best signals as the muscle contractions and movements are taking place. EOG signals will be detected from the movement of the eye muscles in order to direct the cursor up, down, left, and right. EMG signals will be collected from the clenching of the jaw muscles in order to imitate the functions of right and left clicking the mouse. The signals collected from the various eye and jaw movements will need to be amplified to create a justification between stationary placement and mouse movements. The correct amplification will help when interfacing with the mouse.
In the mechanics portion of the project, a wheel mouse will be taken apart in order to understand the features of a mouse. Then, the pulses of specific actions within the mouse will be measured to provide data, which will then be used to interface with the data collected from the electrode signals. The goal is to understand the movements of the mouse by Week 5. However, if this is not possible, a prototype of the movement of the EOG signals using a MATLAB plot to demonstrate the design will be designed instead.
There are several factors that must be considered for the EOG controlled mouse. A major constraint that this project proposes is that of limited sources of signals. Since the design is geared towards quadriplegics, the only muscles available for the collection of signals are those from the neck and above.
To make the use of a computer more natural and efficient, the electrodes must be organized in an strategic manner. This will allow the user to easily control the functions of the computer without the electrodes being too bulky or distracting. To accomplish this, the wires will need to be placed behind the head.
Projected Budget
Quadriplegics do not have control of their extremities, which limits their ability to perform mundane activities such as using a computer. A patient who does not have full control of their hands will experience difficulty when trying to maneuver a mouse to instruct the cursor to move up, down, left, right, or even click on a computer screen. Quadriplegics may have trouble communicating with others and may need various sources of help to lead a manageable life. These sources include physical therapists, occupational therapists, speech pathologists, and attendants. [1]
Pre-Existing Solutions
In the realm of alternate mouse interfaces, there are other attempts to provide a solution such that disabled people can use computers. For example, a study at Stanford University created a software called EyePoint, which is a non-invasive technique that tracks the movement of the eyes using a webcam. The main problem with this technique for mouse interfacing is the need for specialized hardware in order to run this kind of software. Also, this eye tracking device still requires the user to click on a number pad which acts as the “clicking” function on the mouse. This defeats the point of creating an interface for those who do not have access to motor control in their limbs [2]. The video below allows for more insight on the software and includes a demonstration of the EyePoint software.
In addition, there are current studies where disabled patients are using EEG signals in order to control a cursor on a screen. However, the main problem with this alternative is the responsiveness of the cursor once the EEG signals have been captured.
Figure 1: The possible EEG placements.
Design GoalThe goal of the design is to create a device that will allow quadriplegics to control the cursor on a computer screen using EOG signals. This will allow the patients to navigate a computer without the use of their hands. This particular design is different than previous attempts because it will depend solely on the motion of EOG muscles and will be accessible to any operating system since the electronic properties of the mouse will not be altered. Also, the approach is noninvasive because the electrodes will simply be placed on the patient’s face. This allows more flexibility for the patient while still being easy to use.
In order to use the electrodes, multiple tests need to be conducted. The appropriate placement of the electrodes around the eyes and on the jaw will allow for the best signals as the muscle contractions and movements are taking place. EOG signals will be detected from the movement of the eye muscles in order to direct the cursor up, down, left, and right. EMG signals will be collected from the clenching of the jaw muscles in order to imitate the functions of right and left clicking the mouse. The signals collected from the various eye and jaw movements will need to be amplified to create a justification between stationary placement and mouse movements. The correct amplification will help when interfacing with the mouse.
In the mechanics portion of the project, a wheel mouse will be taken apart in order to understand the features of a mouse. Then, the pulses of specific actions within the mouse will be measured to provide data, which will then be used to interface with the data collected from the electrode signals. The goal is to understand the movements of the mouse by Week 5. However, if this is not possible, a prototype of the movement of the EOG signals using a MATLAB plot to demonstrate the design will be designed instead.
Figure 2: EOG Placemet
Design ConstraintsThere are several factors that must be considered for the EOG controlled mouse. A major constraint that this project proposes is that of limited sources of signals. Since the design is geared towards quadriplegics, the only muscles available for the collection of signals are those from the neck and above.
To make the use of a computer more natural and efficient, the electrodes must be organized in an strategic manner. This will allow the user to easily control the functions of the computer without the electrodes being too bulky or distracting. To accomplish this, the wires will need to be placed behind the head.
Another important aspect of consideration for the EOG controlled mouse design is the responsiveness according to the electrical signals from the optical muscles. Mainly, the signal processing needs to be able to identify the differences between different directions for the cursor, as well determine when and how quickly to move. Resolving this constraint will avoid glitches in the interface when users need to perform everyday computing.
Project Deliverables
The physical deliverables pertinent to the completion of the EOG controlled mouse include:
- Completed specification list
- EOG sensor placement and reasoning
- A technique to capture and amplify EOG and EMG signals
- Applied filtering to the EOG and EMG signals
- Illumination of designated LED’s
- Take apart a wheel mouse
- A technique to convert EOG signals into usable signals
- Interface the EOG signals with the mouse signals
- Navigate a cursor on a computer screen using EOG/EMG signals
Project Schedule
| Week | Electrode- team | Mechanical-team |
| 3 | Sensor placement justification; determine specs | Take apart mouse |
| 4 | Amplification design; Signal processing | Run through oscilloscope/determine pulses for specific actions |
| 5 | Signal filtering/ spec matching | Run through oscilloscope/determine pulses for specific actions |
| 6 | Calibration of pulse sensitivity | Run through oscilloscope/determine pulses for specific actions |
| 7 | EOG test/ make sure sensor activation initiates proper LEDs; | Convert LED signals to proper pulses to feed through USB |
| 8 | Assembly of circuit board | Assembly of circuit board |
| 9 | Final touches/error modifications | Final touches/error modifications |
| 10 | Presentation + Report | Presentation + Report |
Figure 3: Schedule for the course of the project.
Projected Budget
- 1 Mouse: $15
- Donated Items:
- Circuit Board
- Electrodes
- Data Acquisition Board
Total Budget: $15
Bibliography
[1] (2006). QUADRIPLEGIA (In Encyclopedia of Special Education: A Reference for the Education of the Handicapped and Other Exceptional Children and Adults.)
[2] K. Greene. (2007, March 2). An Alternative to the Computer Mouse Available. [Online]. Available: http://www.technologyreview.com/computing/18254/
No comments:
Post a Comment