THE$TEAK$PROJECT:$$
TRAVELING$ENGINEERING$ACTIVITY$KITS$
$
$
Artificial Eye
Partial support for this project was provided by the National Science Foundation's Course, Curriculum, and Laboratory
Improvement (CCLI) program under Award No. 0737462. Any opinions, findings, and conclusions or recommendations
expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science
Foundation.
The TEAK Project
!
Rochester Institute of Technology
$
TEAK
Artificial Eye Lesson Plan
Page 2
ACTIVITY OVERVIEW
Artificial Eye Activity Overview
Students completing the Artificial Eye kit will work in teams to build an electrical circuit capable of seeing and
responding to infrared light. Students will adjust the sensitivity of their electrical circuits to detect different
amounts of infrared light. Using analogies between the biological and electrical components of the eye, students
will be shown how engineered devices can be created to mimic some human functions.
Activity
Time
Introduction: Vision
10 min
Constructing a Model Artificial Eye
35-40 min
Description
Students will see the parts of the human eye, as well as the
engineered counterparts that perform similar functions in an
artificial eye
Students will construct an artificial eye that will be able to
see infrared light, using a breadboard and basic electrical
components.
Learning Objectives
By the end of this lesson, students should be able to…
• Explain that the eye is a receptor for human vision.
• Explain that the eye sends visual images to the brain in the form of electrical pulses.
• Recognize that engineers can simulate biological ideals with electrical circuitry to create devices such as
the artificial eye.
• Associate the parts of the artificial eye system to corresponding parts of the human eye system.
NYS Learning Standards
Standard 1: Engineering Design. Engineering design is a repetitive process involving modeling, optimization and
finding the best solution within the given constraints that is used to develop technological and innovative
solutions to technical problems.
• Activate devices
• Recognize why an object or choice is not working properly
• Recognize how a defective simple object or device might be fixed
• Under supervision, manipulate components of a simple, malfunctioning device to improve its
performance
Standard 5: Technology. Students will apply technological knowledge and skills to design, construct, use, and
evaluate products and systems to satisfy human and environmental needs.
• Asemble, operate, and explain the operation of simple open-and closed-loop electrical, electronic,
mechanical, and pneumatic systems
• Describe how system control requires sensing information, processing it, and making changes.
The TEAK Project
!
Rochester Institute of Technology
TEAK
Artificial Eye Lesson Plan
Page 3
TABLE OF CONTENTS
Instructor Preparation Guide.................................................................................................................................. 4!
Bioengineering Overview ....................................................................................................................................... 4!
Human Sight Overview .......................................................................................................................................... 4!
Simplified Definitions ............................................................................................................................................ 4!
Engineering of Sight Overview .............................................................................................................................. 5!
Functions of an Artificial Eye ................................................................................................................................ 5!
Concepts in the Artificial Eye Kit .......................................................................................................................... 6!
Bioengineering Introduction .................................................................................................................................... 8!
Background Information......................................................................................................................................... 8!
Bioengineering Background Group Discussion: 5 Minutes ................................................................................... 8!
Human Sight Introduction ....................................................................................................................................... 9!
Background Information......................................................................................................................................... 9!
Simplified Definitions ............................................................................................................................................ 9!
The Importance of Sight Group Discussion: 5 Minutes ......................................................................................... 9!
Engineering Sight Introduction ............................................................................................................................. 11!
Background Information....................................................................................................................................... 11!
Engineering/Technical Aspects Group Discussion: 5 Minutes ............................................................................ 11!
Learning Objectives .............................................................................................................................................. 12!
Materials ............................................................................................................................................................... 12!
Procedure .............................................................................................................................................................. 12!
Concluding Discussion ......................................................................................................................................... 13!
Artificial Eye Activity Worksheet ......................................................................................................................... 14!
Team Members: .................................................................................................................................................... 14!
Data Tables: .......................................................................................................................................................... 14!
Matching Chart: .................................................................................................................................................... 14!
Artificial Eye Activity Worksheet Answers ......................................................................................................... 15!
Data Tables: .......................................................................................................................................................... 15!
Matching Chart: .................................................................................................................................................... 15!
Activity Instructions ............................................................................................................................................... 16!
List of Materials.................................................................................................................................................... 16!
Building the Artificial Eye ................................................................................................................................... 16!
Artificial Eye Circuit Building Handout .............................................................................................................. 17!
Biology Sheet ........................................................................................................................................................... 19!
Matching of Biological Equivalent Components ................................................................................................. 19!
Engineering Sheet ................................................................................................................................................... 20!
Image Sources ......................................................................................................................................................... 21!
Extended Information/Resources .......................................................................................................................... 21!
Revisions .................................................................................................................................................................. 22!
Signifies Activity
Signifies Group Discussion
The TEAK Project
!
Rochester Institute of Technology
TEAK
Artificial Eye Lesson Plan
Page 4
INSTRUCTOR PREPARATION GUIDE
Bioengineering Overview
Bioengineering is the application of science, mathematics and engineering principles to define and provide
solutions to problems in the fields of biology and medicine. An example of a product created by bioengineers is
the artificial eye.
Human Sight Overview
The human eye is a complex organ. Its function can be broken down into three stages.
1. The first stage is the collection of light. At the front of the eye, a lens stretches or contracts to adjust the
visual focal point. This allows an individual to focus on objects that are either far or close to the
individual.
2. The second stage is the processing of visual light. At the back of the eye, there are two types of receptors
called cones and rods. Cones help the individual to detect and distinguish different colors. The human
eye has blue, green and red cones. Rods help the individual to detect and distinguish between light and
dark.
3. The third stage is the process of stimulating the brain. After a receptor is stimulated, an electrical pulse is
sent out through the optic nerve to the visual cortex of the brain. This is the area of the human brain
where visual stimuli are processed.
Figure 1 - The Human Eye
Simplified Definitions
Cones: Receptors in the eye that are stimulated by colors
Rods: Receptors in the eye that are stimulated by different intensities of light
Optic Nerve: A sensory nerve that allows the receptors in the eye to send electrical pulses to the brain
Visual Cortex: The area of the brain that processes vision. This is located in the back region of the brain, the
occipital lobe. If you fall on the back of the head and you see stars, it is because the visual cortex of the brain was
stimulated by the shock of falling.
The TEAK Project
!
Rochester Institute of Technology
TEAK
Artificial Eye Lesson Plan
Page 5
Engineering of Sight Overview
Individuals with visual problems could have damaged or defective lenses, receptors, or even optic nerves.
Engineers and scientist have been studying how the human eye works and functions in hopes to find solutions for
the visual impaired. Currently, bioengineers are working to develop a device called the artificial eye. The
artificial eye is a device that can replace the second and last stages of the eye to allow the individual to process
information and stimulate the brain.
Figure 2 – Artificial Eye Implants
Functions of an Artificial Eye
1. The first stage is the collection and focusing of light. If an individual has a problem with their lens, they
suffer from nearsightedness or farsightedness.
• Nearsightedness – A condition in which an individual has difficulty viewing objects from a
distance.
• Farsightedness – A condition in which an individual has difficulty viewing objects from a close
distance.
Solutions to these problems include obtaining glasses, or contact lenses, or even laser vision surgery
2. The second stage is the processing of visual light. Engineers have thought of two ways to replace human
receptors
• Camera – Engineers can attach a micro camera to a pair of glasses to easily allow an individual to
obtain vision. However, this attachment is noticeable to others and requires the transfer of large
signals to the visual cortex. Thus, large bulky wiring is required to be sent from the glasses,
through the human skull, and into the brain. Wireless transmission of these signals is currently
being investigated.
The TEAK Project
!
Rochester Institute of Technology
TEAK
Artificial Eye Lesson Plan
Page 6
•
Electrodes – Engineers have also devised a plan to implant electrodes into the human eye. These
implants will contain millions of electrodes to stimulate different locations of human sight. The
more electrodes that can be implemented, the sharper the image the artificial eye can send to the
user. However this technology is not fully developed.
3. The third stage is the process of stimulating the brain. Stimulating the brain with electrical pulses is not a
problem for engineers. The main problem for engineers is finding the right location of the brain to
stimulate for images to appear accurately.
Concepts in the Artificial Eye Kit
1. The following kit is designed to operate with infrared light signals. Infrared light signals are safe and can
also be found in television remote controls. These signals are not visible to the human eye.
2. The following kit operates with an operational amplifier. This allows small readings to be amplified. In
this circuit, the larger the resistance used, the larger the gain; in other words, the system becomes more
sensitive.
3. To increase the distance of operation, a larger resistance is required to increase the gain or sensitivity to
light.
4. Raising the resistance too high is similar to having no resistor at all, and will give an infinite gain. In this
scenario, the output light will never turn off. (The artificial eye will not stop stimulating the brain.)
5. To simplify the circuit for students to build, the circuit does not operate at far distances. This kit should
operate from within a foot.
6. The students are to find the optimal resistance so that the light operates at moderate distances and still
turns off.
The TEAK Project
!
Rochester Institute of Technology
TEAK
Artificial Eye Lesson Plan
Page 7
The Artificial Eye Activity
Figure 3 – Artificial Eye Implant
DURATION
45-50 Minutes
CONCEPTS
Bioengineering
Human Sight Systems
Engineering Sight
Artificial Eye Activity
The TEAK Project
!
Rochester Institute of Technology
TEAK
Artificial Eye Lesson Plan
Page 8
BIOENGINEERING INTRODUCTION
Background Information
Bioengineering is the application of science, mathematics and engineering principles to define and provide
solutions to problems in the fields of biology and medicine. An example of a product created by bioengineers is
the artificial eye.
Bioengineering Background Group Discussion: 5 Minutes
(Pose the following questions to the group and let the discussion flow naturally…try to give
positive feedback to each child that contributes to the conversation.)
Q: What do you think bio (biology) means?
•
•
•
The study of life and a branch of the natural sciences that studies living organisms and how they interact
with each other and their environment.
The study of the environment.
The study of living organisms and living systems.
Q: What do you think engineering is? What do you think it means to be an engineer?
•
A technical profession that applies skills in:
o Math
o Science
o Technology
o Materials
o Structures
Discuss with the students what bioengineering is and the broad scope of areas that bioengineering includes.
For this discussion, provide students with examples of bioengineer products and applications.
• Bioengineering applies engineering principles in the fields of medicine, biology, robotics, and any other
living system.
• Examples of products that have been bioengineered are:
o Artificial Hearts
o Artificial Heart Valves
o Stents
o Catheters
The TEAK Project
!
Rochester Institute of Technology
TEAK
Artificial Eye Lesson Plan
Page 9
HUMAN SIGHT INTRODUCTION
Background Information
The power of sight is one of the five senses humans have. Sight is processed by an impressive organ called the
eye. The human eye can detect shades of light and shades of colors. When light reflects off an object, these
shades of light and shades of colors are collected by our receptors in the eye. Receptors then send electrical
pulses to the brain for processing via the optic nerve.
Simplified Definitions
Cones: Receptors in the eye that are stimulated by colors
Rods: Receptors in the eye that are stimulated by different intensities of light
Optic Nerve: A sensory nerve that allows the receptors in the eye to send electrical pulses to the brain
Visual Cortex: The area of the brain that processes vision. This is located in the back region of the brain, the
occipital lobe. If you fall on the back of the head and you see stars, it is because the visual cortex of the brain was
stimulated by the shock of falling.
The Importance of Sight Group Discussion: 5 Minutes
(Pose the following questions to the group and let the discussion flow naturally…try to give
positive feedback to each child that contributes to the conversation.)
Q: What are the five human senses?
•
•
•
•
•
Seeing
Hearing
Tasting
Touching
Smelling
The TEAK Project
!
Rochester Institute of Technology
TEAK
Artificial Eye Lesson Plan
Page 10
Q: If you were to lose the sense of sight how would life be different? Give a few examples of some daily
difficulties
• Having a hard time cooking
• Having a hard time walking
• Having a hard time being aware of their own surroundings
Hand out papers and pens to each student. With the students’ eyes opened, have them write their names on the
piece of paper and draw their own hand (without sketching around their own hand). With the students’ eyes
closed, have them write their names on the piece of paper and draw their own hand again. Ask the students if it
was more difficult to write and draw with their eyes closed.
Q: What kind of diet can help maintain healthy eyes?
•
•
•
Eating carrots can help with keeping health vision
Carrots contain vitamin A – this is an essential vitamin for maintaining healthy vision
Vitamin A can also be found in milk, egg yolks, and cheese
Q: What is the difference between nearsightedness and farsightedness?
•
•
Nearsightedness – Condition in which an individual has difficulties viewing objects from a distance.
Farsightedness – Condition in which an individual has difficulties viewing objects from a close distance.
Q: What are some animals with excellent vision?
•
•
•
Eagles - eyesight about 3-4 times better than a human
Vultures - keen eyes for seeing far distances
Owls - excellent night vision
The TEAK Project
!
Rochester Institute of Technology
TEAK
Artificial Eye Lesson Plan
Page 11
ENGINEERING SIGHT INTRODUCTION
Background Information
Engineers and scientist have been studying how the human eye works and functions in hopes of finding a solution
for the visually impaired. Currently, bioengineers are working to develop a device called the artificial eye. The
artificial eye is a device that allows the individual to receive and process light, and stimulate the brain.
Engineering/Technical Aspects Group Discussion: 5 Minutes
(Pose the following questions to the group and let the discussion flow naturally…try to give
positive feedback to each child that contributes to the conversation.)
Q: How can engineers replicate receptors in the eye?
•
•
With the use of electrodes that respond to light signals
With the use of a camera
The human brain responds to and sends out electrical pulses. To communicate with the human brain, engineers
construct devices that can send and receive electrical pulses. However the human brain is complex and differs
from person to person. Can anyone think of some difficulties engineers must deal with?
• Engineers do not know the location in which to stimulate or receive signals to or from the brain
• Implanting electrodes into the human eye
• Designing electrical pulse for different individuals
• Stimulating the brain to know the difference between light, dark, or different colors
The TEAK Project
!
Rochester Institute of Technology
TEAK
Artificial)Eye)Activity)–25)Minutes)
Artificial Eye Lesson Plan
Page 12
Learning Objectives
By the end of this exercise, students should be able to…
• Describe and identify the biological equivalent of parts of the artificial eye kit
• Describe and identify the engineering parts of the artificial eye kit
• Create and use the data table to find optimal performances of a circuit
Materials
1.
2.
3.
4.
5.
6.
7.
Infrared LED Flashlight
Photodiode LED (Black)
Red LED (Clear)
Yellow LED (Yellow)
Breadboard (Pre-wired)
IC Chip
2 AAA Batteries
8.
9.
10.
11.
12.
13.
Battery Holder
Switch
Resistors (68Ω, 10 Ω, 100 Ω, 1k Ω, 1 M Ω)
Capacitor (1 pF)
Laminated Biology Sheet
Laminated Engineering Sheet
Procedure
1. Students should be working in teams, with two students per team. Assign roles for each member of a
group: a Design Engineer and a Performance Engineer. Have the model eyeball demonstrated in
front of class.
2. Have the Design Engineer collect the necessary materials for the group. This student will follow the
illustrated Activity Instruction sheet to construct the artificial eye onto the breadboard. Have the
student build with the 1 kΩ resistor first. This resistor value will allow the circuit to operate at a fair
distance.
3. While the Design Engineer is constructing the artificial eye kit, have the Performance Engineer test
the infrared LED flashlight with the model eyeball in the front of the class.
4. Have the Performance Engineer test the circuit. This student will place different resistors onto the
breadboard for testing. They will be testing the circuit for its maximum distance of the infrared LED
Flashlight operating with their artificial eye kit. Each distance will be recorded in a data table under
the Artificial Eye Activity Worksheet.
5. Have each group decide which resistor is best for the artificial eye. Then have both engineers work
together to fill out the Matching Chart portion of the Artificial Eye Activity Worksheet.
The TEAK Project
!
Rochester Institute of Technology
TEAK
Artificial Eye Lesson Plan
Page 13
End)Artificial)Eye)Activity)
Concluding Discussion
Have the class go over the Artificial Eye Activity Worksheet.
Ask the students the following questions:
Q: With what resistor value did the red LED stay constantly on?
Q: With what resistor value did the circuit operate the furthest with the ability to turn off?
Have the class take a poll of which resistor is best for the more optimal artificial eye circuit.
• The answer should be the 1 MΩ resistor
Q: Can anyone guess why a person might see stars when he/she falls down on their back side of their head?
(Do not allow students to test this theory!)?
• A blow to the back of a person’s head stimulated the optical lobe which can cause a person to think he/she
sees stars
Q: What are some problems with the artificial eye stimulating the brain?
•
Engineers and Scientists have a hard time stimulating the exact location of the brain
Q: What is another application of the artificial eye?
•
Engineers can implant artificial eyes to robots
Tell the class some fun facts about the human eye:
1. A shark’s cornea is similar to that of a human’s and is sometimes used in eye surgery.
2. People generally read 25% slower from a computer screen than compared to reading from a piece
of paper.
3. All babies are color blind when they are born.
The TEAK Project
!
Rochester Institute of Technology
TEAK
Artificial Eye Lesson Plan
Page 14
ARTIFICIAL EYE ACTIVITY WORKSHEET
Team Members:
Design Engineer:
Performance Engineer:
_____________________________________
_____________________________________
Data Tables:
Testing the Artificial Eye
Resistor Values
Maximum Distance Still Working (inches)
10 Ω
100 Ω
1 kΩ
1MΩ
No resistor
Matching Chart:
Match the following components from the Biological Human Eye column to the Engineered Artificial Eye
column by drawing a line connecting between the items that match. (See Biology Sheet for additional assistance)
Biological Human Eye
A. Eye
B. Cones and Rods Receptors
C. Optic Nerve
D. Occipital Lobe (Back of Brain)
Engineered Artificial Eye
1. Infrared LED (Black LED)
2. Red LED
3. IC Chip
4. Wires
The TEAK Project
!
Rochester Institute of Technology
TEAK
Artificial Eye Lesson Plan
Page 15
ARTIFICIAL EYE ACTIVITY WORKSHEET ANSWERS
Data Tables:
Testing the Artificial Eye
Resistor Values
Maximum Distance Still Working (inches)
10 Ω
100 Ω
1 kΩ
1MΩ
No resistor
0
~1
~4
~10
Never Turns Off
Matching Chart:
Biological Human Eye
A. Eye
B. Cones and Rods Receptors
C. Optic Nerve
D. Occipital Lobe (Back of Brain)
Engineered Artificial Eye
1. Infrared LED (Black LED)
2. Red LED
3. IC Chip
4. Wires
A=1
B=3
C=4
D=2
The TEAK Project
!
Rochester Institute of Technology
TEAK
Artificial Eye Lesson Plan
Page 16
ACTIVITY INSTRUCTIONS
List of Materials
PART
Infrared LED Flashlight
Photodiode LED (Black)
Red LED (Clear)
Yellow LED (Yellow)
Breadboard (Pre-wired)
IC Chip (Given out by instructor)
2 AAA Batteries
Battery Holder
Switch (Already glued to Breadboard)
Resistors ( 10Ω, 100Ω, 1 kΩ, 1MΩ)
Capacitor - 1pF
FUNCTION
Emits infrared light
Receives infrared light
Represents electrical pulse sent to the brain
Indicates power is on
Platform for kit
Processes electrical signals
Provides power to the kit
Incases the battery
Turns the kit on or off
Used for gain adjustments
Assist in processing electrical signals
Building the Artificial Eye
1. Check to see all materials listed above are available. (Note: The IC Chip is very delicate and will
be given out by the instructor)
2. Place the electrical components listed on the back into the breadboard slots indicated by the
pictures. (Excluding the resistors)
3. Take the 1kΩ resistor and place it into slots D8 and A9 of the breadboard (orientation does not
matter). To modify the performance of the Artificial Eye, this resistor value may be altered by
the Performance Engineer.
a.
b.
c.
d.
e.
10Ω resistor (Color code Brown Black Red)
100Ω resistor (Color code Brown Black Orange)
1kΩ resistor (Color code Brown Black Yellow)
1MΩ resistor (Color code Brown Black Green)
No resistor (Having no resistor equals infinite resistance)
4. Remove and set aside (do not lose) the pink stopper from the Infrared LED Flashlight. Using the
flashlight, test the maximum distance the circuit detects the infrared light and record the results
on the worksheet.
The TEAK Project
!
Rochester Institute of Technology
1. Note: the
E8
F8
TEAK
Artificial Eye Lesson Plan
Page 17
orientation of the dot
2.
Place
the
battery
E9
F9
and notch in the IC
onto the
ARTIFICIAL
EYE CIRCUITpack
BUILDING
HANDOUT
E10
F10
chip indicate the top.
breadboard in the
Note: The Numeric and Alphas enclosed in boxes represent locations on the breadboard
Place the IC chip on
following
E11
F11
the breadboard with
orientation.
the pins in the
I 25
I 20
following
orientation.
3. Place the Yellow LED onto
4. Locate the
the breadboard in the following
capacitor and place
orientation. Note: The straight
one of the prongs in
wire on the LED goes to the
B9 and the other in
Blue Line on the Breadboard,
B10. Orientation
while the bent wire goes to
does not matter
position B30.
Blue
Line
B30
D5
A8
www.webaddress.edu/something
!
B10
6. Place the Photodiode
LED, which is black,
onto the breadboard in
the following
orientation.
5. Place the Red LED, which is
clear, onto the breadboard in the
following orientation. Note: The
straight wire on the LED goes to
the Blue Line on the Breadboard,
while the bent wire goes to
position B30.
Blue
Line
B9
The TEAK Project
G5
Rochester Institute of Technology
TEAK
7. Locate the Resistor
(10Ω, 100Ω, 1K Ω, 1M Ω)
and place one end into D8
and the other end into A9.
The orientation does not
matter.
www.webaddress.edu/something
!
10Ω
Artificial Eye Lesson Plan
100Ω
Page 18
1KΩ
1MΩ
The TEAK Project
Rochester Institute of Technology
TEAK
Artificial Eye Lesson Plan
Page 19
BIOLOGY SHEET
Matching of Biological Equivalent Components
Answer the following questions below then use the answers to match the biological components of an eye to the electrical components of the Artificial Eye
Name the receptors that
convert light signals into
electrical signals.
What body part is used for
receiving light signals?
www.webaddress.edu/something
!
How do electrical
signals travel from the
eye to the brain?
The TEAK Project
What region of the brain
is stimulated by the
visual electrical signals?
Rochester Institute of Technology
What electrical
omponent !can be
sed for receiving
nfrared light?
TEAK
Answer the following questions below.
Artificial Eye Lesson Plan
How does electricity
travel between the
Think about the similarities between the electrical components in the eye kit and the organs in the body.
components?
ENGINEERING SHEET
Which component
eacts when an
lectrical signal is
eceived?
What electrical
component can be
used for processing
signals?
The TEAK Project
!
Page 20
Rochester Institute of Technology
TEAK
Artificial Eye Lesson Plan
Page 21
!
IMAGE SOURCES
[1] Schubert, E. F. Light-Emiting Diods. Cambridge University. JPEG file.
http://www.ecse.rpi.edu/~schubert/Light-Emitting-Diodes-dot-org/chap16/F16-01%20Human%20eye.jpg
[2] The Bionic Man Wears Glasses. 2007. News as Cyberpunk. JPEG file.
http://www.cyberpunkreview.com/news/bionic-eyechip3.jpg
[3] Jen. MS Optic Nerve Attacks and Symptoms. 2008. MS Strength. JPEG file.
http://www.msstrength.com/ms-optic-nerve-attacks-and-symptoms/
[4] Hecker, Miles. Light—Color & Human Vision. 2001. The Luminous Landscape. JPEG file.
http://www.luminous-landscape.com/tutorials/color_and_vision.shtml
EXTENDED INFORMATION/RESOURCES
Rods and Cones
http://hyperphysics.phy-astr.gsu.edu/hbase/vision/rodcone.html
Nearsighted and Farsighted
http://www.everydayhealth.com/vision-center/the-eye-exam/nearsighted-farsighted.aspx
Bionic Eye Video
http://www.youtube.com/watch?v=GZ0G9odShF4
The TEAK Project
!
Rochester Institute of Technology
TEAK
Artificial Eye Lesson Plan
Page 22
REVISIONS
Date
Changes Made
Changes Made By
3/26/2013
Updated formatting. Added table of contents and
work cited page. Fixed grammar and syntax
issues.
Todd Jackson
www.webaddress.edu/something
!
The TEAK Project
Rochester Institute of Technology