LESSON PLANS
History of Computing – EEEEK- A Mouse!
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The History of Computing – EEEEK a Mouse! activity explores the concept of how engineering solved the problem of human/computer interface. Students disassemble a mouse and explore the movement on the X/Y axis that determines mouse positioning.
Age Levels: 8-18
Required Materials
Design Challenge
You are a team of engineers given the challenge of disassembling a unusable “track ball” mouse, using the materials provided to you. You will then observe the mechanical parts of the mouse. Next, you will develop and share improvements you would make to eliminate or strengthen an operating feature/part. Finally, you will design and build a model of the part.
Criteria
Constraints
The lesson can be done in as little as 1 class period for older students. However, to help students from feeling rushed and to ensure student success (especially for younger students), split the lesson into two periods giving students more time to brainstorm, test ideas and finalize their design. Conduct the testing and debrief in the next class period.
Divide into teams
Review the challenge and criteria constraints
Brainstorm possible solutions (sketch while you brainstorm!)
Choose best solution and build a prototype
Test then redesign until solution is optimized
Reflect as a team and debrief as a class
Mouse Operation and Innovation
The purpose of the computer mouse is to translate human motion (use of the hand) into messages or signals that the computer can translate into directions for moving the screen cursor or to open an application.
X – Y Navigation of the Track Ball Mouse
Inside a standard track ball mouse is a round rubber ball that when moved adjusts the position of either one or two bars which send movement signals that are converted to computer messages telling computer software where to move a cursor on a computer screen. The “bars” usually have a wheel or “optical encoding disks” that usually include 36 holes or slots that allow light to pass. Small, infrared LEDs (light emitting diodes) point to the disk and the pattern or pulses of light that pass through the holes in the disk are converted to “X” and “Y” positions provide computer software with a sense of the distance and direction which the ball has moved. In this way the two dimensional motion of the mouse can be translated into the motion of a pointer within computer software. When you disassemble a track ball mouse in the student activity, you’ll be able to see the two bars, and the optical encoding disks, and how the ball movement impacts these other mechanisms when rolled on a surface.
Click Click Click
The mouse buttons make a “click” noise when pressed for two reasons….one, the pressing pushes on a “micro switch” that incorporates a very stiff piece of metal that snaps….two, the sound has been proven to improve the human/computer interface, giving the user an audible feedback that their finger has caused an action.
Engineered Improvements
Over time, many new engineered improvements have taken the mouse to the next level, or been developed to address specific human needs. For example there are mice with oversized balls on top (instead of underneath) for easier use by very small children or people with physical challenges. There are “roller ball” mice which have additional wheels and switches to activate advanced functions in software. There are fingerprint reader mice, which will only operate if the fingerprint of the user is accepted by the mouse as indicating an approved user. And most people now use wireless mice, which allow for greater freedom of movement, and also remote movement. There are “tactile” mice which vibrate when the user reaches a boundary or physical limit in gameware or software. Probably the most widely integrated recent change is the “optical” mouse which completely eliminated the tracking ball and instead projects a LED (light emitting diode) onto the tracking surface which bounces back and is picked up by a CMOS (complementary metal-oxide semiconductor) sensor. It basically takes thousands of “pictures” each second and as the resulting patterns change it translates the changes into motion and speed patterns. Makes of “optical” mice claim that they will last longer because the bottom is sealed so dust and oils cannot enter the mouse, and there are fewer moving parts to break.
Internet Connections
Recommended Reading
Writing Activity
Write an essay or a paragraph describing how engineering has changed another product over time. Choose from the following products: television, toaster, light bulb, automobile transmission.
Note: Lesson plans in this series are aligned to one or more of the following sets of standards:
CONTENT STANDARD E: Science and Technology
As a result of activities in grades K-4, all students should develop
CONTENT STANDARD B: Physical Science
As a result of the activities, all students should develop an understanding of
CONTENT STANDARD F: Science in Personal and Social Perspectives
As a result of activities, all students should develop understanding of
CONTENT STANDARD G: History and Nature of Science
As a result of activities, all students should develop understanding of
CONTENT STANDARD B: Physical Science
As a result of their activities, all students should develop an understanding of
CONTENT STANDARD E: Science and Technology
As a result of activities in grades 5-8, all students should develop
CONTENT STANDARD F: Science in Personal and Social Perspectives
As a result of activities, all students should develop understanding of
CONTENT STANDARD G: History and Nature of Science
As a result of activities, all students should develop understanding of
CONTENT STANDARD B: Physical Science
As a result of their activities, all students should develop understanding of
CONTENT STANDARD E: Science and Technology
As a result of activities, all students should develop
CONTENT STANDARD F: Science in Personal and Social Perspectives
As a result of activities, all students should develop understanding of
CONTENT STANDARD G: History and Nature of Science
As a result of activities, all students should develop understanding of
The Nature of Technology
Technology and Society
Design
Abilities for a Technological World
The Designed World
Dissect a Mouse – Component Parts
Step One: As a team, disassemble either a new (inexpensive) or old unusable “track ball” mouse, using the materials provided to you. Be sure that the mouse is not connected to a computer and that no power is flowing through it. You will need to use a very small screwdriver, such as the type commonly found in eyeglass repair kits. Be careful as you pull the plastic cover off the mouse.
Step Two: Observe the mechanical parts that move when you move the roller ball. Also observe the two or three “switches” and see how they can click when the mouse case has been removed.
Questions:
What new materials will you need (if any) | What materials or parts will you eliminate (if any) | How will this new design address the shortcoming you identified? | How do you think your new design will impact the cost of this mouse? Why? |
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