Change Can Be a Good Thing!

Week 4:

During the week four lab, the plan was to connect the mouse to the oscilloscope to determine what each wire in the mouse specifically controls (for example, moving left or right clicking), which would give a better understanding of how the mouse works. This would also be helpful when interfacing the signals from the EOG tests with the mouse to control the movement on the screen.

After examining the internal system of the mouse, there was a realization that there was a a micro-computer chip that converts the movements from the mouse into digital signals that the computer can read.  This chip seen in Figure 1 was pre-programmed, so it would be very difficult to interpret the signals of the mouse from the wires. The signals would not give readings for the individual movements of the mouse.

                              

 Figure 1: Close-Up View of the Pre-Programmed Micro-Computer Chip (Black Rectangle on the Left)

Entirely, the idea of interfacing the mouse with the electrode signals would be too difficult and time consuming, due to the complexity of the computer chip inside and the wires. Because of this, it was ultimately decided that a MATLAB simulation program would be created to see how a mouse can control the cursor on a computer screen instead of actually interfacing with the wheel mouse. Essentially, there will be a MATLAB window that will act as a computer screen and there will be a code that will work in conjunction with the electrode signals captured to replicate the idea of an EOG controlled mouse.  

Because of the changes made, the week's procedure was slightly altered.  During the remainder of the time period, the mechanical team, now mainly the MATLAB programming team, watched tutorial videos to assist in creating the MATLAB program later on in the project. The video tutorials provide a basis for the complicated code that needs to be written, especially helpful for Freshmen with minor MATLAB programming experience.

The Anatomy of a Mouse!

Week 3:

         The first thing attempted this week for the project on the mechanics side was to try to understand how a wheel mouse works. To do this, an ordinary wheel mouse was taken apart in order to see how the mechanics work and how everything was put together. Below in Figure 1 is a diagram of the components of the mouse labeled with their respective functions. Basically, there is a rubber ball located on the underside of the mouse. The ball is kept in place by a spring that forces the ball against the top and left sides. Because the ball is against these sides, when the mouse is moved, the ball rotates the top and side rods. The top rod is moved when the mouse is moved vertically, and the side rod is moved when the mouse is moved horizontally. The rod then spins the wheels, which are made with little plastic spokes around the edges (seen in Figure 2). There is a light emitter that goes through these spokes and is read by a light detector. The number of times the beam is detected by the light detector is the way that the computer measures how far and how quickly the mouse is being pushed. Besides those main parts of the mouse, there is also a chip that converts the mouse movements into digital signals that can be read by the computer. Towards the top of the mouse are switches that detect the right and left clicks of the mouse.  There is also a scroll wheel in the center. Like all circuit boards, there is a capacitor and resistors (not labeled due to lack of space). Lastly, there are different wires (as of yet, their exact functions are unknown) that connect to a PS/2, which is an outdated connection to the computer. Because of this, a converter to USB is currently being ordered so the mouse can be connected to laptops.

Figure 1: Labeled Diagram of the Components of a Wheel Mouse

Figure 2: Close-Up View of the Wheel along with the LED Emitter and Receptor

http://www.explainthatstuff.com/computermouse.html

        Also, one of the goals of the week for the electrode team was to research how an electrode interface would be implemented. In addition to learning where to place the electrodes on the user, it was also important to find out the magnitude of signal being received from each electrode. That way, there would be a better understanding as to what extent the raw input should be amplified. 

        Below in Figure 3 shows the configuration of the electrodes when placed on the user's face. These electrodes will capture the EOG signals when the user moves their eyes. This signal is produced when light enters the retina, where the light signal is processed into a neural signal.

Figure 3: Sensor Placements for EOG Signals

http://www.waset.org/journals/waset/v31/v31-57.pdf

"With Great Power Comes Great Responsibility"

Week 2:

               After finally deciding on a project topic, the group used the class time to discuss the final decision with the advisor. The proposed idea was approved, so from there the roles of the project were assigned. Jasmin and Gabrielle were assigned the role of Mouse Prototyping Interface. Maxime was assigned the role of Physiological Interfacing via Instrumentation. Jenna was assigned the role of Signal Processing and Extraction. Once the roles were assigned, a general timeline for the project was established, as seen in Table 1.

Table 1: Schedule for the course of the project

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

          After creating the weekly goals of the project, this blogging website was created in order to keep track of the weekly activities. It will be updated at least once a week to show the progress of the project. In week 3, a project proposal page will be posted, which is what the remainder of this week's lab period was dedicated to.

Bioelectrically Controlled Devices

                Week 1:

                In Section 33 held on Tuesday from 1-3, the project topic is "Bioelectrically Controlled Devices".  This topic is mainly geared towards Biomedical Engineers with an interest who have an interest in Biomedical devices. Bioelectrically controlled devices usually involve the use of signals gathered by sensors from muscle movements, such as EOG or EMG sensors, along with amplifiers. Projects under this topic can deal with actions such as muscle movements, brain activity, and even the cardiac cycle. The Biomedical Engineering field has been able to produce a large amount of Bioelectrically Controlled Devices in the past few years, so this is definitely a prevalent field of study and a great topic for students to explore.

                Even though this Engineering lab section has a proposed topic, the specific project of each group will vary and needs to be determined. Group 8 had a difficult time coming up with a subtopic, so a meeting with DJ, the project advisor, was set up to discuss possible projects. Some of the project ideas were as follows:

• An airplane simulation game controlled by eye and arm muscle movements
• Controlling the duck hunt video game with arm muscle contractions
• Controlling a computer mouse via the use of EOG and EMG signals
• Controlling an E-reader with eye movements

                The general consensus of group 8 was to focus on a Bioelectrically Controlled Device that would be an assistive, making it more relevant to the Biomedical Engineering field.  Because of this, the ultimate decision was to make the project "EOG Controlled Mouse Movement".