KRISHNA INSTITUTE OF TECHNOLOGY
KANPUR
SYNOPSIS
On
‘EYE TRACKER MOUSE’
Under the Guidance of :-
Name Of Students :-
Ms. Harshita Nigam
Akash Kumar
Ashish Kumar Shukla
Diwakar Awasthi
Kartik Vats
Prashsnt Singh Kanaujiya
Shyam Kumar
ABSTRACT
With a growing number of computer devices around us, and the increasing time we spend for interacting
with such devices, we are strongly interested in finding new interaction methods which ease the use of
computers or increase interaction efficiency. Eye tracking seems to be a promising technology to achieve
this goal.
The object of this paper is to present a set of techniques integrated into a low-lost eye tracking system.
Eye tracking systems have many potential applications such as learning emotion monitoring systems,
drivers' fatigue detection systems, etc. In this paper, we report how we use an eye tracking system to
implement an "eye mouse" to provide computer access for people with severe disabilities. The proposed
eye mouse allows people with severe disabilities to use their eye movements to manipulate computers.
In the cases of paralysis a person’s ability to move may be limited to the muscles around the eyes, which
may be the only way for him to communicate. We developed a computationally efficient and cost
effective application for controlling the mouse cursor using the eye ball by real time tracking using IR
sensor.
In this paper, an individual human computer interface system using eye motion is introduced.
Traditionally, human computer interface uses mouse, keyboard as an input device. This paper presents
hands free interface between computer and human. This technology is intended to replace the
conventional computer screen pointing devices for the use of disabled. The paper presents a novel idea to
control computer mouse cursor movement with human eyes It controls mouse-moving by automatically
affecting the position where eyesight focuses on, and simulates mouse-click by affecting blinking action.
However, the proposed vision-based virtual interface controls system work on various eye movements
such as eye blinking.
Key Points: Arduino ATMega8.
 Gyroscope Sensor.
 IR Sensor.
INTRODUCTION
With the invention of the computer in the middle of the last century there was also the need of an
interface for users. In the beginning experts used teletype to interface with the computer. Due to the
tremendous progress in computer technology in the last decades, the capabilities of computers increased
enormously and working with a computer became a normal activity for nearly everybody. With all the
possibilities a computer can offer, humans and their interaction with computers are now a limiting factor.
This gave rise to a lot of research in the field of HCI (human computer interaction) aiming to make
interaction easier, more intuitive, and more efficient. Interaction with computers is not limited to
keyboards and printers anymore. Different kinds of pointing devices, touch-sensitive surfaces, highresolution displays, microphones, and speakers are normal devices for computer interaction nowadays.
There are new modalities for computer interaction like speech interaction, input by gestures or by
tangible objects with sensors.
A further input modality is eye gaze which nowadays finds its application in accessibility systems. Such
systems typically use eye gaze as the sole input, but outside the field of accessibility eye gaze can be
combined with any other input modality. Therefore, eye gaze could serve as an interaction method
beyond the field of accessibility. The aim of this work is to find new forms of interactions utilizing eye
gaze and suitable for standard users.
Recently there has been a growing interest in developing natural interaction between human and
computer. Several studies for human-computer interaction in universal computing are introduced. The
vision-based interface technique extracts motion information without any high cost equipments . Realtime eye input has been used most frequently for disabled users, who can use only their eyes for input.
This paper is aimed for designing and implementing a human computer interface system that tracks the
direction of the human eye. The particular motion as well as direction of the iris is employed to drive the
interface by positioning the mouse cursor consequently.
AIM AND USES OF PROJECTS
This Infrared Eye Tracking Mouse uses some interesting methods of creating a eye controlled computer
mouse. The intent is that you would be able to ditch the desk mouse and simply put on a pair of glasses.
The system would be a self contained battery operated system that doesn’t have you tethered to your
computer with a cable.We have a pair of 3-D printed glasses with plastic lenses. These lenses have holes
drilled into them to mount thru-hole infrared LEDs and phototransistors. The emitter is positioned above
the eye and emits IR light, which is reflected off of the eye into the phototransistors below the eye .
We also have a small gyroscope breakout board in the center of our glasses above the bridge, which will
detect head movements in three axes of rotation. All of these glasses-mounted components are connected
to a microcontroller, which parses the LED and gyroscope data into USART packets and transmits it
wirelessly. The packets are read by a wireless receiver on a separate ATMega1284P board, which moves
the mouse cursor using a Java program based on the information received.”
Real-time eye input has been used most frequently for disabled users, who can use only their eyes for
input.
Eye tracking mouse is used in the computer world for interact with computer without touching any
physical device. It will used to control computer programs and any computer applications like playing
games.
“Eye Tracking Mouse” is boon for the disable people who are not able to use physical mouse properly. It
will gives them a new way to interact with computer world. It opens a new erain computer technology. It
is efficient in real time applications which give speed and accuracy of the system.
The aim was the design of a low-cost combined eye- and head tracking system for persons with motoric
deficiencies of their upper limbs. The system will thereby be used to control a mouse curser. The
following parts were to be developed:
 Sensor board (Microcontroller).
 Firmware
 Circuit board
 Infrared-LED frame.
 Integration of the sensor board into an existing eye tracking.
 Processing sensor board data to estimate the head pose
 Merging the eye tracking and head pose data
This apparatus is not only very handy for healthy computer users. Also for people with severe motor
disabilities it could be the only possible alternative to communicate with their environment. Diseases like
amyotrophic lateral sclerosis (ALS), which consists out of a paralysis of the muscles, eyes are the only
way to control the environment (Donegan et al., 2006). With the use of an eye tracker these people
(partially) regain the capability of controlling their wheelchair or other elements of their environment.
SYSTEM BLOCK DIAGRAM
Arduino ATMega8
Arduino is an open source electronics prototyping platform based on flexible, easy to use hardware and
software. It offers a variety of digital and analog inputs,SPI ,serial interface ,digital and PWM outputs.It
is easy to use ,connects to computer via USB and communications using serial protocol,runs in
standalone mode and as interface connected to PC.It is inexpensive and comes with free authoring
software.Arduino is a micro controller board using on theATmega8.ATMega8 has:Memory: It has 8 Kb of Flash program memory (10,000 Write/Erase cycles durability), 512 Bytes of
EEPROM (100,000 Write/Erase Cycles). 1Kbyte Internal SRAM
I/O Ports: 23 I/ line can be obtained from three ports; namely Port B, Port C and Port D.
Interrupts: Two External Interrupt source, located at port D. 19 different interrupt vectors supporting 19
events generated by internal peripherals.
Timer/Counter: Three Internal Timers are available, two 8 bit, one 16 bit, offering various operating
modes and supporting internal or external clocking.
SPI (Serial Peripheral interface): ATmega8 holds three communication devices integrated. One of
them is Serial Peripheral Interface. Four pins are assigned to Atmega8 to implement this scheme of
communication.
USART: One of the most powerful communication solutions is USART and ATmega8 supports both
synchronous and asynchronous data transfer schemes. It has three pins assigned for that. In many
projects, this module is extensively used for PC-Micro controller communication.
TWI (Two Wire Interface): Another communication device that is present in ATmega8 is Two Wire
Interface. It allows designers to set up a commutation between two devices using just two wires along
with a common ground connection, As the TWI output is made by means of open collector outputs, thus
external pull up resistors are required to make the circuit.
Analog Comparator: A comparator module is integrated in the IC that provides comparison facility
between two voltages connected to the two inputs of the Analog comparator via External pins attached to
the micro controller.
Analog to Digital Converter: Inbuilt analog to digital converter can convert an analog input signal into
digital data of 10bit resolution. For most of the low end application, this much resolution is enough.
Summary
Microcontroller
Operating Voltage
Input-Voltage
(recommended)
Input Voltage
(limits)
Digital I/O Pins
Analog Input Pins
DC Current per
I/O Pin
DC Current for
3.3V Pin
Flash Memory
SRAM
EEPROM
Clock Speed
ATmega8L
5V
7-12V
6-20V
14 (of which 6 provide PWM output)
6
40 mA
50 mA
32 KB (ATmega8L) of which 0.5 KB used by bootloader
2 KB (ATmega328)
1 KB (ATmega328)
16 MHz
Power
The Arduino Uno can be powered via the USB connection or with an external power supply. The power
source is selected automatically.
External (non-USB) power can come either from an AC-to-DC adapter (wall-wart) or battery. The
adapter can be connected by plugging a 2.1mm center-positive plug into the board's power jack. Leads
from a battery can be inserted in the Gnd and Vin pin headers of the POWER connector.
The board can operate on an external supply of 6 to 20 volts. If supplied with less than 7V, however, the
5V pin may supply less than five volts and the board may be unstable. If using more than 12V, the
voltage regulator may overheat and damage the board. The recommended range is 7 to 12 volts.
The power pins are as follows:
 VIN. The input voltage to the Arduino board when it's using an external power source (as
opposed to 5 volts from the USB connection or other regulated power source). You can supply
voltage through this pin, or, if supplying voltage via the power jack, access it through this pin.
 5V.This pin outputs a regulated 5V from the regulator on the board. The board can be supplied
with power either from the DC power jack (7 - 12V), the USB connector (5V), or the VIN pin of
the board (7-12V). Supplying voltage via the 5V or 3.3V pins bypasses the regulator, and can
damage your board. We don't advise it.
 3V3. A 3.3 volt supply generated by the on-board regulator. Maximum current draw is 50 mA.
 GND. Ground pins.
 IOREF. This pin on the Arduino board provides the voltage reference with which the
microcontroller operates. A properly configured shield can read the IOREF pin voltage and select
the appropriate power source or enable voltage translators on the outputs for working with the 5V
or 3.3V.
Memory
The ATmega8L has 32 KB (with 0.5 KB used for the bootloader). It also has 2 KB of SRAM and 1 KB
of EEPROM (which can be read and written with the EEPROM library).
Input and Output
Each of the 14 digital pins on the Uno can be used as an input or output, using pinMode(), digitalWrite(),
and digitalRead() functions. They operate at 5 volts. Each pin can provide or receive a maximum of 40
mA and has an internal pull-up resistor (disconnected by default) of 20-50 kOhms. In addition, some pins
have specialized functions:
 Serial: 0 (RX) and 1 (TX). Used to receive (RX) and transmit (TX) TTL serial data. These pins
are connected to the corresponding pins of the ATmega8U2 USB-to-TTL Serial chip.
 External Interrupts: 2 and 3. These pins can be configured to trigger an interrupt on a low
value, a rising or falling edge, or a change in value. See the attachInterrupt() function for details.
 PWM: 3, 5, 6, 9, 10, and 11. Provide 8-bit PWM output with the analogWrite() function.
 SPI: 10 (SS), 11 (MOSI), 12 (MISO), 13 (SCK). These pins support SPI communication using
the SPI library.
 LED: 13. There is a built-in LED connected to digital pin 13. When the pin is HIGH value, the
LED is on, when the pin is LOW, it's off.
The Uno has 6 analog inputs, labeled A0 through A5, each of which provide 10 bits of resolution (i.e.
1024 different values). By default they measure from ground to 5 volts, though is it possible to change
the upper end of their range using the AREF pin and the analogReference() function. Additionally, some
pins have specialized functionality:
 TWI: A4 or SDA pin and A5 or SCL pin. Support TWI communication using the Wire library.
There are a couple of other pins on the board:
 AREF. Reference voltage for the analog inputs. Used with analogReference().
 Reset. Bring this line LOW to reset the microcontroller. Typically used to add a reset button to
shields which block the one on the board.
Communication
The Arduino Uno has a number of facilities for communicating with a computer, another Arduino, or
other microcontrollers. The ATmega8L provides UART TTL (5V) serial communication, which is
available on digital pins 0 (RX) and 1 (TX). An ATmega16U2 on the board channels this serial
communication over USB and appears as a virtual com port to software on the computer. The '16U2
firmware uses the standard USB COM drivers, and no external driver is needed. However, on Windows,
a .inf file is required . The Arduino software includes a serial monitor which allows simple textual data to
be sent to and from the Arduino board. The RX and TX LEDs on the board will flash when data is being
transmitted via the USB-to-serial chip and USB connection to the computer (but not for serial
communication on pins 0 and 1).
ATMega8L Pin Diagram:-
SENSOR
A sensor is a device that detects events or changes in quantities and provides a corresponding output,
generally as an electrical or optical signal; for example, a thermocouple converts temperature to an output
voltage. But a mercury-in-glass thermometer is also a sensor; it converts the measured temperature into
expansion and contraction of a liquid which can be read on a calibrated glass tube.
Sensors are used in everyday objects such as touch-sensitive elevator buttons (tactile sensor) and lamps
which dim or brighten by touching the base, besides innumerable applications of which most people are
never aware. With advances in micro machinery and easy-to-use microcontroller platforms, the uses of
sensors have expanded beyond the more traditional fields of temperature, pressure or flow measurement,
for example into MARG sensors. Moreover, analog sensors such as potentiometers and force-sensing
resistors are still widely used. Applications include manufacturing and machinery, airplanes and
aerospace, cars, medicine and robotics.
Sensors need to be designed to have a small effect on what is measured; making the sensor smaller often
improves this and may introduce other advantages. Technological progress allows more and more sensors
to be manufactured on a microscopic scale as micro sensors using MEMS technology. In most cases, a
micro sensor reaches a significantly higher speed and sensitivity compared with macroscopic approaches.
All living organisms contain biological sensors with functions similar to those of the mechanical devices
described. Most of these are specialized cells that are sensitive to:
 Light, motion, temperature, magnetic fields, gravity, humidity, moisture, vibration, pressure,
electrical fields, sound, and other physical aspects of the external environment
 Physical aspects of the internal environment, such as stretch, motion of the organism, and position
of appendages (proprioception)
 Environmental molecules, including toxins, nutrients, and pheromones
 Estimation of biomolecules interaction and some kinetics parameters
 Internal metabolic indicators, such as glucose level, oxygen level, or osmolality
 Internal signal molecules, such as hormones, neurotransmitters, and cytokines
 Differences between proteins of the organism itself and of the environment or alien creatures.
Sensors are two types
 Active sensors
 Passive sensors
Active sensors are sensors that transmit some kind of energy ( microwave , sound , light , .... ) into the
environment in order to detect the changes that occur on the transmitted energy . That means it transmits
and detect at the same time : Require an external source of power (excitation voltage) that provides the
majority of the output power of the signal . But passive sensors don't transmit energy but only detects the
energy transmitted from an energy source, e.g. motion detectors which are mostly passive infrared
sensors. The output power is almost entirely provided by the measured signal without an
excitation voltage.
GYROSCOPE
A gyroscope (from Greek gûros, "circle" and skopéo,"to look") is a device for measuring or maintaining
orientation, based on the principles of angular momentum. Mechanical gyroscopes typically comprise a
spinning wheel or disc in which the axle is free to assume any orientation. Although the orientation of
the spin axis changes in response to an external torque, the amount of change and the direction of the
change is less and in a different direction than it would be if the disk were not spinning. When mounted
in a gimbal (which minimizes external torque), the orientation of the spin axis remains nearly fixed,
regardless of the mounting platform's motion. Gyroscopes based on other operating principles also
exist, such as the electronic, microchip-packaged MEMS gyroscope devices found in consumer electronic
devices, solid-state ring lasers, fibre optic gyroscopes, and the extremely sensitive quantum gyroscope.
Gyro sensors, also known as angular rate sensors or angular velocity sensors, are devices that sense
angular velocity. In simple terms, angular velocity is the change in rotational angle per unit of time.
Angular velocity is generally expressed in deg/s (degrees per second). In recent years vibration gyro
sensors have found their way into camera-shake detection systems for compact video and still cameras,
motion sensing for video games, and vehicle electronic stability control (anti-skid) systems, among other
things. Vibration gyro sensors sense angular velocity from the Coriolis force applied to a vibrating
element. For this reason, the accuracy with which angular velocity is measured differs significantly
depending on element material and structural differences. Here, we briefly describe the main types of
elements used in vibration gyro sensors. The motion of a pair of sensing arms produces a potential
difference from which angular velocity is sensed. The angular velocity is converted to, and output as, an
electrical signal.
There are three basic types of gyroscope
 Rotary (classical) gyroscopes
 Vibrating Structure Gyroscope
 Optical Gyroscopes
Rotary Gyroscope
The classic gyroscope exploits the law of conservation of angular momentum which, simply stated, says
that the total angular momentum of a system is constant in both magnitude and direction if the resultant
external torque acting upon the system is zero4). These gyroscopes typically consist of a spinning disk or
mass on an axle, which is mounted on a series of gimbals. Each gimbal offers the spinning disk an
additional degree of rotational freedom. The gimbals allow the rotor to spin without applying any net
external torque on the gyroscope. Thus as long as the gyroscope is spinning, it will maintain a constant
orientation. Gimballed gyroscope, showing how each gimbal offers an additional degree of rotational
freedom. Taken from http://commons.wikimedia.org/wiki/File:Gyroscope_operation.gif When external
torques or rotations about a given axis are present in these devices, orientation can be maintained and
measurement of angular velocity can be measured due to the phenomenon of precession.
Precession occurs when an object spinning about some axis (the spin axis) has an external torque applied
in a direction perpendicular to the spin axis (the input axis). In a rotational system when net external
torques are present, the angular momentum vector (which is along the spin axis) will move in the
direction of the applied torque vector. As a result of the torque, the spin axis rotates about an axis that is
perpendicular to both the input axis and spin axis (called the output axis). A torque about the input axis
produces precession about the output axis. Taken from [3].
This rotation about the output axis is then sensed and fed back to the input axis where a motor or similar
device applies torque in the opposite direction, cancelling the precession of the gyroscope and
maintaining its orientation. This cancellation can also be accomplished with two gyroscopes oriented at
right angles to one another.
To measure rotation rate, counteracting torque is pulsed at regular time intervals. Each pulse represents a
fixed angular rotation δθ, and the pulse count in a fixed time interval t will be proportional to the net
angle change θ over that time period – thus, the applied counteracting torque is proportional to the
rotation rate to be measured3).
Today rotary gyroscopes are mainly used in stabilization applications. The presence of moving parts
(gimbals, rotors) means that these gyroscopes can wear out or jam. A number of bearing types have been
developed to minimize the wear and chance for jamming in these gyroscopes 5) 6). Another consequence
of moving parts is that it limits how small these gyroscopes can be. Thus rotary gyroscopes are mostly
used today in harsh military and naval environments which are subject to shock and intense vibration,
and where physical size is not critical. These units are therefore not readily commercially available.
Vibrating Structure Gyroscope
Vibrating structure gyroscopes are MEMS (Micro-machined Electro-Mechanical Systems) devices that
are easily available commercially, affordable, and very small in size. Fundamental to an understanding of
the operation of an vibrating structure gyroscope is an understanding of the Coriolis force. In a rotating
system, every point rotates with the same rotational velocity. As one approaches the axis of rotation of
the system, the rotational velocity remains the same, but the speed in the direction perpendicular to the
axis of rotation decreases. Thus, in order to travel in a straight line towards or away from the axis of
rotation while on a rotating system, lateral speed must be either increased or decreased in order to
maintain the same relative angular position (longitude) on the body. The act of slowing down or speeding
up is acceleration, and the Coriolis force is this acceleration times the mass of the object whose longitude
is to be maintained. The Coriolis force is proportional to both the angular velocity of the rotating object
and the velocity of the object moving towards or away from the axis of rotation.
Vibrating structure gyroscopes contain a micro-machined mass which is connected to an outer housing
by a set of springs. This outer housing is connected to the fixed circuit board by a second set of
orthogonal springs.
The mass is continuously driven sinusoidally along the first set of springs. Any rotation of the system
will induce Coriolis acceleration in the mass, pushing it in the direction of the second set of springs. As
the mass is driven away from the axis of rotation, the mass will be pushed perpendicularly in one
direction, and as it is driven back toward the axis of rotation, it will be pushed in the opposite direction,
due to the Coriolis force acting on the mass.
When the mass is driven upward, a Coriolis force acts on the mass, pushing it left. When the mass is
driven downward, the Coriolis force acts in the opposite direction. .
The Coriolis force is detected by capacitive sense fingers that are along the mass housing and the rigid
structure. As the mass is pushed by the Coriolis force, a differential capacitance will be detected as the
sensing fingers are brought closer together. When the mass is pushed in the opposite direction, different
sets of sense fingers are brought closer together; thus the sensor can detect both the magnitude and
direction of the angular velocity of the system 7) .
The complete basic setup, showing how the capacitive sense fingers move as the Coriolis force acts on
the mass. Taken from [7].
Optical Gyroscope
Optical gyroscopes were developed soon after the discovery of laser technology. The appeal of this type
of gyroscope is that they contain no moving parts, and hence are not susceptible to mechanical wear or
drifting. Optical gyroscopes differ from other types in that they do not rely on conservation of angular
momentum in order to operate. Instead, their functionality depends only on the constancy of the speed of
light.
Optical gyroscopes operate under the principle of the Sagnac effect. It easiest to understand this principle
in the general case of a circle. A light source is positioned on a circle, emitting two beams of light in
either direction. If the source stays stationary, then both beams of light require an equal amount of time to
traverse the circle and arrive back at the source. However, if the source is rotating along the circle, then it
takes more time for the beam in front of the source to complete its path.
Schematic This principle can in fact be generalized to any loop, regardless of shape. In particular, we can
measure the effect using a ring interferometry setup. Here, a laser beam is first split by a half silvered
mirror. Then the two beams traverse identical paths but opposite directions around a loop consisting of
either flat mirrors and air-filled straight tubes or a long fibre-optic cable. These two beams then
recombine at a detector. When the system is rotating, one of the beams must travel a greater distance than
the opposite traveling beam to make it to the detector. This difference in path length (or Doppler shift) is
detected as a phase shift by interferometry. This phase shift is proportional to the angular velocity of the
system5). Often optical gyroscope units consist of 3 mutually orthogonal gyroscopes for rotation sensing
about all three orthogonal rotation axes. They are also typically implemented with 3-axis accelerometers
thus providing full motion sensing in 6 DoF. Like rotor gyroscopes, optical gyroscopes are limited in
how physically small they can get, due to the extensive amount of fibre-optic cable needed and presence
of optical equipment. Thus these gyroscopes are often used in naval and aviation applications, and where
physical size is not an issue.
A gyroscope sensor has the following basic specifications:






Measurement range
Number of sensing axes
Nonlinearity
Working temperature range
Shock survivability
Bandwidth
Measurement range – This parameter specifies the maximum angular speed with which the sensor can
measure, and is typically in degrees per second (˚/sec).
Number of sensing axes – Gyroscopes are available that measure angular rotation in one, two, or three
axes. Multi-axis sensing gyros have multiple single-axis gyros oriented orthogonal to one another.
Vibrating structure gyroscopes are usually single-axis (yaw) gyros or dual-axis gyros, and rotary and
optical gyroscope systems typically measure rotation in three axes.
Nonlinearity – Gyroscopes output a voltage proportional to the sensed angular rate. Nonlinearity is a
measure of how close to linear the outputted voltage is proportional to the actual angular rate. Not
considering the nonlinearity of a gyro can result in some error in measurement. Nonlinearity is measured
as a percentage error from a linear fit over the full-scale range, or an error in parts per million (ppm).
Working temperature range – Most electronics only work in some range of temperatures. Operating
temperatures for gyroscopes are quite large; their operating temperatures range from roughly -40˚C to
anywhere between 70 and 200˚C and tend to be quite linear with temperature. Many gyroscopes are
available with an onboard temperature sensor, so one does not need to worry about temperature related
calibrations issues.
Shock Survivability – In systems where both linear acceleration and angular rotation rate are measured,
it is important to know how much force the gyroscope can withstand before failing. Fortunately
gyroscopes are very robust, and can withstand a very large shock (over a very short duration) without
breaking. This is typically measured in g’s (1g = earth’s acceleration due to gravity), and occasionally the
time with which the maximum g-force can be applied before the unit fails is also given.
Bandwidth – The bandwidth of a gyroscope typically measures how many measurements can be made
per second. Thus the gyroscope bandwidth is usually quoted in Hz.
IR SENSOR
A passive infrared sensor (PIR sensor) is an electronic sensor that measures infrared (IR) light radiating
from objects in its field of view. They are most often used in PIR-based motion detectors. All objects
with a temperature above absolute zero emit heat energy in the form of radiation. Usually this radiation is
invisible to the human eye because it radiates at infrared wavelengths, but it can be detected by electronic
devices designed for such a purpose.
The term passive in this instance refers to the fact that PIR devices do not generate or radiate any energy
for detection purposes. They work entirely by detecting the energy given off by other objects.[1] PIR
sensors don't detect or measure "heat"; instead they detect the infrared radiation emitted or reflected from
an object. An infrared sensor is an electronic instrument which is used to sense certain characteristics of
its surroundings by either emitting and/or detecting infrared radiation. Infrared sensors are also capable of
measuring the heat being emitted by an object and detecting motion.
Infrared waves are not visible to the human eye. In the electromagnetic spectrum, infrared radiation can
be found between the visible and microwave regions. The infrared waves typically have wavelengths
between 0.75 and 1000µm.
The wavelength region which ranges from 0.75 to 3µm is known as the near infrared regions. The region
between 3 and 6µm is known as the mid-infrared and infrared radiation which has a wavelength greater
higher than 6µm is known as far infrared.
Infrared technology finds applications in many everyday products. Televisions use an infrared detector to
interpret the signals sent from a remote control. The key benefits of infrared sensors include their low
power requirements, their simple circuitry and their portable features.
Infrared radiation was first discovered by the astronomer William Herschel. He conducted an experiment
in which he used a prism to refract light from the sun. Herschel was able to detect the presence of
infrared radiation beyond the red part of the visible spectrum using a thermometer to measure an increase
in temperature. In 1800 Herschel published his findings to the Royal Society of London.
Infrared sensors are broadly classified into two main types:
Thermal infrared sensors – use infrared energy as heat. Their photo sensitivity is independent of the
wavelength being detected. Thermal detectors do not require cooling but do have slow response times
and low detection capabilities.
Quantum infrared sensors – provide higher detection performance and faster response speed. Their
photo sensitivity is dependent on wavelength. Quantum detectors have to be cooled in order to obtain
accurate measurements.
Working Principle of Infrared Sensors:All objects which have a temperature greater than absolute zero (0 Kelvin) posses thermal energy and are
sources of infrared radiation as a result.
Sources of infrared radiation include blackbody radiators, tungsten lamps and silicon carbide. Infrared
sensors typically use infrared lasers and LEDs with specific infrared wavelengths as sources.
A transmission medium is required for infrared transmission, which can be comprised of either a vacuum,
the atmosphere or an optical fiber.
Optical components, such as optical lenses made from quartz, CaF2, Ge and Si, polyethylene Fresnel
lenses and Al or Au mirrors, are used to converge or focus the infrared radiation. In order to limit spectral
response, band-pass filters can be used.
Next, infrared detectors are used in order to detect the radiation which has been focused. The output from
the detector is usually very small and hence pre-amplifiers coupled with circuitry are required to further
process the received signals.
Estimated Cost of Project
Parts
ITG3200 Gyroscope Breakout
Board
ATMega8L Breakout Boards
Power Supply
9V Battery
RCR-433-RP Receiver
RCT-433-AS Transmitter
Glasses
CQY36N Infrared LEDs
Wires, Resistors,
Capacitor,Inductors
Phototransistors, PCB
components,
connector cables,etc
TOTAL COST OF PROJECT
Quantity
1
Total Estimated Cost(Rs.)
700
2
1
1
1
1
1
10
Many
800
300
300
300
300
100
400
300
3500