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Eman Fatima-11
Areej shahid-12
Ayesha Fayyaz-13
Anam Anwar-18
Ayesha Shoukat- 29
Ayeza Saif-31
Saman Ijaz-55
Group 06
Submitted to: Ma’am Anum Noor
Section: (A)
Government college for women university, Sialkot
Bs Chemistry (2018-2022)
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Table of Content
Sr
no.
Topics
Page no
1
Definition
3
Characteristics
2
What are sensor material made of
5
3
Graphene
6
4
Carbon nanotubes
8
5
Types of Sensors
9
6
Top Applications of sensors
16
7
References
18
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Topic: Research in sensor materials
Defination:
“Sensor materials are natural manifestation of physical sensors. These material
changes their state and properties in a particular way while they are sensing physical
changes.”
The scheme for a general sensor system is shown in figure 1. However, each sensor is
different depending on its application, and so the energy transformation. In appendix A,
both the energy forms and transductions between these energy forms are shown
Characteristics of Sensors
Range: It is the minimum and maximum value of physical variable that the sensor can
sense or measure. For example, a Resistance Temperature Detector (RTD) for the
measurement of temperature has a range of -200 to 800oC.
Span: It is the difference between the maximum and minimum values of input. In above
example, the span of RTD is 800 – (-200) = 1000oC.
Accuracy: The error in measurement is specified in terms of accuracy. It is defined as the
difference between measured value and true value. It is defined in terms of % of full scale
or % of reading. Xt is calculated by taking mean of infinite number of measurements.
Precision: It is defined as the closeness among a set of values. It is different from accuracy.
Let Xt be the true value of the variable X and a random experiment measures X1, X2, ….
Xi as the value of X. We will say our measurements X1, X2,… Xi are precise when they
are very near to each other but not necessarily close to true value Xt. However, if we say
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X1, X2,… Xi are accurate, it means that they are close to true value Xt and hence they are
also close to each other. Hence accurate measurements are always precise.
Sensitivity: It is the ratio of change in output to change in input. If Y be the output quantity
in response to input X, then sensitivity S can be expressed as
Linearity: Linearity is the maximum deviation between the measured values of a sensor
from ideal curve.
Hysteresis: It is the difference in output when input is varied in two ways- increasing and
decreasing.
Resolution: It is the minimum change in input that can be sensed by the sensor.
Reproducibility: It is defined as the ability of sensor to produce the same output when same
input is applied.
Repeatability: It is defined as the ability of sensor to produce the same output every time
when the same input is applied and all the physical and measurement conditions kept the
same including the operator, instrument, ambient conditions etc.
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Response Time: It is generally expressed as the time at which the output reaches a certain
percentage (for instance, 95%) of its final value, in response to a step change of the input.
What are sensor materials made of?
The ceramics used in sensors typically fall into two categories. Those made from
conventional (traditional) ceramic materials, typically very tough in nature, and those
which are made up of piezoceramic materials which are typically softer, generating an
electrical charge when squeezed.
Traditional Ceramics:
Traditional ceramics are used in sensors when toughness and durability are required.
Traditional ceramic sensors are used when electrical fields are present, due to high electric
fields limiting the use of piezoceramics. Traditional ceramics are used in different
environments to piezoceramic sensors, often being used in environments where there is
more stress and or/heat. This is because sensors made from traditional ceramics tend to
have higher resistance to large amounts of stress, are less likely to depolarize under multiple
heating cycles, and typically exhibit a lower hysteresis than piezoceramic sensors. Several
ceramic materials can be used in these sensors but require a high temperature tolerance, be
robust, have a long usable life, can undergo direct contact with harsh media (especially
liquids) and be washable (if they are to be inserted into specific mediums). This has meant
that materials such as alumina, zirconia and yttria, as well as toughened/reinforced versions
of these materials, have become some of the common materials used as the sensing surface.
They are widely used as temperature and pressure sensors in their application. However,
their chemical inertness and ability to be used in a wide range media means they are also
used for sensing gases (such as oxygen) and corrosion in different environments, as well
as being used in proximity sensing, capacitive sensing, oil level sensors, measuring the
flow of harsh chemicals, and monitoring ingredient flows in the food and beverage
industry.
Piezoceramic sensors:
Due to piezoceramic sensors exhibiting a very useful phenomenon known as the
piezoelectric effect, they have become a widespread class of sensors. The piezoelectric
effect comes to fruition when a piezoelectric material is subjected to a physical force, as
the force causes the charges in the atomic lattice to move to a point where all like charges
accumulate at one end of the material, and the opposite like charges accumulate at the
opposite end of the material. The result is the generation of an electrical charge across the
material that can be detected.
Due to this, there are many piezoelectric and piezoresistive sensors which are made of
ceramic materials. One of the main application areas for piezoceramic sensors is physical
sensors, such as strain gauges/stress-strain sensors, as the application of a physical force
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on the ceramic material generates an electrical current which can be detected. However,
there are number of physical forces that can generate these currents—such as compression
and elongation—meaning that several environments subjected to physical deformations
can utilize piezoceramic sensors.
However, it is not just the piezoceramic sensors ability to generate a detectable charge as
to why they are a popular ceramic sensor choice. Piezoceramics tend to have greater
electromechanical coupling factors, piezoelectric constants, permittivities, and dielectric
constants than traditional ceramic sensors, but are not as mechanically robust. In recent
years, the evolution of nanomaterials has broadened the scope of piezoceramic sensors.
Many inorganic ceramic nanomaterials also exhibit the piezoelectric effect and can be
made smaller and thinner than other piezoceramic materials, opening up piezoceramic
sensors to new areas of application.
The two ways in which piezoceramics are classified are; active and passive piezoceramic
sensors.
• Active piezoceramic sensors are used to measure the time-of-flight between a
transmitter and a receiver. In these cases, the ceramic will be at its resonant
frequency, acting as a transmitter, and in an anti-resonant state if acting as a
receiver. Specific examples of active piezoceramic sensors include strain gauges
on buildings (during construction and after completion), in level sensors, medical
ultrasound devices, and flow sensors.
• Passive piezoceramic sensors In this the ceramics operate below their
resonance frequency level, meaning they can be applied across a wide frequency
range and for a broader band response. This means passive piezoceramic sensors
are well-suited for accelerometer, hydrophone, microphone and musical pick-up
applications.
Graphene:
Graphene is an allotrope of carbon consisting of a single layer of atoms arranged in a
two-dimensional honeycomb lattice. The name is a portmanteau of "graphite" and the
suffix -ene, reflecting the fact that the graphite allotrope of carbon consists of stacked
graphene layers.
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Graphene detects, ultra-sensitive sensors made from graphene could detect minute
dangerous particles helping to protect potentially dangerous environments.
Graphene sensors
Graphene is an ideal material for sensors. Every atom in graphene is exposed to its
environment allowing it to sense changes in its surroundings. For chemical sensors,
the goal is to be able to detect just one molecule of a potentially dangerous substance.
Graphene now allows for the creation of micrometre-size sensors capable of detecting
individual events on a molecular level.
Reducing food waste
Graphene oxide can be used to create 'smart' food packaging products. This could
dramatically cut down on unnecessary food wastage and simultaneously help prevent
illnesses. Packaging which has been coated with graphene has the ability to detect
atmospheric changes caused by decaying food.
Crop protection
Graphene sensors could boost the effectiveness of monitoring vital crops in the agriculture
industry. Farmers would be able to monitor the existence of any harmful gasses which
could impact upon crop fields and take relevant action. As graphene sensors are so sensitive
it is feasible that they could determine the ideal areas for growing certain crops depending
on atmospheric conditions.
Carbon nanotubes:
Carbon nanotubes (CNTs) are cylindrical molecules that consist of rolled-up sheets of
single-layer carbon atoms (graphene). They can be single-walled (SWCNT) with a
diameter of less than 1 nanometer (nm) or multi-walled (MWCNT), consisting of several
concentrically interlinked nanotubes, with diameters reaching more than 100 nm. Their
length can reach several micrometers or even millimeters.
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CNT as biosensors
Carbon nanotubes (CNTs) are cylindrical molecules that consist of rolled-up sheets of
single-layer carbon atoms (graphene). They can be single-walled (SWCNT) with a
diameter of less than 1 nanometer (nm) or multi-walled (MWCNT), consisting of several
concentrically interlinked nanotubes, with diameters reaching more than 100 nm. Their
length can reach several micrometers or even millimeters.
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TYPES OF SENSORS:
1. Vision and Imaging Sensors
Vision and Imaging Sensors/Detectors are electronic devices that detect the presence of
objects or colors within their fields of view and convert this information into a visual image
for display. Key specifications include sensor type and intended application, along with
any particular transducer features.
2. Temperature Sensors
Temperature Sensors/Detectors/Transducers are electronic devices that detect thermal
parameters and provide signals to the inputs of control and display devices. A temperature
sensor typically relies on an RTD or thermistor to measure temperature and convert it to
an output voltage. Key specifications include sensor/detector type, maximum and
minimum measurable temperatures, as well as the dimensions of diameter and length.
Temperature sensors are used to measure the thermal characteristics of gases, liquids, and
solids in many process industries and are configured for both general- and special-purpose
uses.
Applications:
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Temperature Sensors are used everywhere like computers, mobile phones, automobiles, air
conditioning systems, industries etc.
3. Radiation Sensors
Radiation Sensors/Detectors are electronic devices that sense the presence of alpha, beta,
or gamma particles and provide signals to counters and display devices. Key specifications
include sensor type and minimum and maximum detectable energies. Radiation detectors
are used for surveys and sample counting.
4. Proximity Sensors
Proximity Sensors are electronic devices used to detect the presence of nearby objects
through non-contacting means. A proximity sensor can detect the presence of objects
usually within a range of up to several millimeters, and, doing so, produce a usually dc
output signal to a controller. Proximity sensors are used in countless manufacturing
operations to detect the presence of parts and machine components. Key specifications
include sensor type, maximum sensing distance, minimum & maximum operating
temperatures, along with dimensions of diameter and length. Proximity sensors are
generally short-range devices but are available too in designs that can detect objects up to
several inches away. One commonly used type of proximity sensor is known as a capacitive
proximity sensor. This device uses the change in capacitance resulting from a reduction in
the separation distance between the plates of a capacitor, one plate of which is attached to
the object being observed, as a means of determining motion and position of the object
from the sensor.
Applications:
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Some of the applications of Proximity Sensors areMobile Phones, Cars (Parking Sensors),
industries (object alignment), Ground Proximity in Aircrafts, etc.
Proximity Sensor in Reverse Parking is implemented in this Project: REVERSE PARKING
SENSOR CIRCUIT.
5. Pressure Sensors
Pressure Sensors/Detectors/Transducers are electro-mechanical devices that detect forces
per unit area in gases or liquids and provide signals to the inputs of control and display
devices. A pressure sensor/transducer typically uses a diaphragm and strain gage bridge to
detect and measure the force exerted against a unit area. Key specifications include sensor
function, minimum and maximum working pressures, full-scale accuracy, along with any
features particular to the device. Pressure sensors are used wherever information about the
pressure of a gas or liquid is needed for control or measurement.
6. Position Sensors
Position Sensors/Detectors/Transducers are electronic devices used to sense the positions
of valves, doors, throttles, etc. and supply signals to the inputs of control or display devices.
Key specifications include sensor type, sensor function, measurement range, and features
that are specific to the sensor type. Position sensors are used wherever positional
information is needed in a myriad of control applications. A common position transducer
is a so-called string-pot, or string potentiometer.
7. Photoelectric Sensors
Photoelectric sensors are electrical devices that sense objects passing within their field of
detection, although they are also capable of detecting color, cleanliness, and location if
needed. These sensors rely on measuring changes in the light they emit using an emitter
and a receiver. They are common in manufacturing and material handling automation for
purposes such as counting, robotic picking, and automatic doors and gates.
8. Motion Sensors
Motion Sensors/Detectors/Transducers are electronic devices that can sense the movement
or stoppage of parts, people, etc. and supply signals to the inputs of control or display
devices. Typical applications of motion detection are detecting the stalling of conveyors or
the seizing of bearings. Key specifications include the intended application, sensor type,
sensor function, and minimum and maximum speeds.
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9. Metal Sensors
Metal Detectors are electronic or electro-mechanical devices used to sense the presence of
metal in a variety of situations ranging from packages to people. Metal detectors can be
permanent or portable and rely on a number of sensor technologies with electromagnetics
being popular. Key specifications include the intended application, maximum sensing
distance, and certain feature choices like handheld and fixed systems. Metal detectors can
be tailored to explicitly detect metal in specific manufacturing operations such as
sawmilling or injection molding.
10.
Level Sensors
Level Sensors/Detectors are electronic or electro-mechanical devices used for determining
the height of gases, liquids, or solids in tanks or bins and providing signals to the inputs of
control or display devices.
Typical level sensors use ultrasonic, capacitance, vibratory, or mechanical means to
determine product height.
Key specifications include sensor type, sensor function, and maximum sensing distance.
Level sensors/detectors can be of the contacting or non-contacting type.
11.
Leak Sensors
Leak Sensors/Detectors are electronic devices used for identifying or monitoring the
unwanted discharge of liquids or gases. Some leak detectors rely on ultrasonic means to
detect air leaks, for example. Other leak detectors rely on simple foaming agents to measure
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the soundness of pipe joints. Still, other leak detectors are used to measure the effectiveness
of the seals in vacuum packages.
12.
Humidity Sensors
Humidity Sensors/Detectors/Transducers are electronic devices that measure the amount
of water in the air and convert these measurements into signals that can be used as inputs
to control or display devices. Key specifications include maximum response time and
minimum and maximum operating temperatures.
13.
Gas and Chemical Sensors
Gas and Chemical Sensors/Detectors are fixed or portable electronic devices used to sense
the presence and properties of various gases or chemicals and relay signals to the inputs of
controllers or visual displays. Key specifications include the intended application,
sensor/detector type, measurement range, and features. Gas and chemical sensors/detectors
are used for confined space monitoring, leak detection, analytical instrumentation, etc. and
are often designed with the capability of detecting multiple gases and chemicals.
Application:
Gas Sensors are more common in laboratories, large scale kitchens and industries. They
can detect different gases like LPG, Propane, Butane, Methane (CH4), etc.
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14.
Flame Sensors
Flame Detectors are optoelectronic devices used to sense the presence and quality of fire
and provide signals to the inputs of control devices. A flame detector typically relies on
ultraviolet or infrared detection of the presence of flame and finds use in many combustion
control applications such as burners. A key specification is detector type. Flame detectors
find applications in safety settings too, such as in under-the-hood fire suppression systems..
15.
Electrical Sensors
Electrical Sensors/Detectors/Transducers are electronic devices that sense current, voltage,
etc. and provide signals to the inputs of control devices or visual displays. Electrical sensors
often rely on hall effect detection but other methods are used as well. Key specifications
include sensor type, sensor function, minimum and maximum measurement ranges, and
operating temperature range. Electrical sensors are used wherever information on the state
of an electrical system is needed and are employed in everything from railway systems to
fan, pump, and heater monitoring.
16.
Contact Sensors
Contact sensors refer to any type of sensing device that functions to detect a condition by
relying on physical touch or contact between the sensor and the object being observed or
monitored. A simple type of contact sensor is used in alarm systems to monitor doors,
windows, and other access points. When the door or window is closed, a magnetic switch
provides an indication to the alarm control unit so that the status of that entry point is
known. Similarly, when a door or window is opened, the contact sensor alerts the alarm
controller of the state of that access point and may trigger an action such as engaging an
audible siren. There are many uses of contact sensors such as temperature monitoring and
as proximity sensors in robotics applications and automated machinery.
17.
Non-Contact Sensors
In contrast to contact sensors, non-contact sensors are devices that do not require a physical
touch between the sensor and the object being monitored in order to function. A familiar
example of this type of sensor is the motion detector used in security lights. Detection of
objects within the range of a motion detector is accomplished using non-mechanical or
non-physical means, such as via detection of passive infrared energy, microwave energy,
ultrasonic waves, etc. Radar guns used by law enforcement to monitor the speed of vehicles
is another example of a form of non-contact sensor. Other types of devices that fall under
the category of non-contact sensors include Hall-effect sensors, inductive sensors, LVDTs
(linear variable differential transformers), RVDTs (rotary variable differential
transformers), and Eddy current sensors, to name a few.
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18.
Touch Sensor
We do not give much importance to touch sensors but they became an integral part of our
life. Whether you know or not, all touch screen devices (Mobile Phones, Tablets, Laptops,
etc.) have touch sensors in them. Another common application of touch sensor is trackpads
in our laptops. Touch Sensors, as the name suggests, detect touch of a finger or a stylus.
Often touch sensors are classified into Resistive and Capacitive type. Almost all modern
touch sensors are of Capacitive Types as they are more accurate and have better signal to
noise ratio.
19.
Light Sensor
Sometimes also known as Photo Sensors, Light Sensors are one of the important sensors.
A simple Light Sensor available today is the Light Dependent Resistor or LDR. The
property of LDR is that its resistance is inversely proportional to the intensity of the
ambient light i.e., when the intensity of light increases, its resistance decreases and
viseversa.
Applications
Street lights work on this principle on night time they automatically becomes on and off at
day time.
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20.
Ultrasonic Sensor
An Ultrasonic Sensor is a non-contact type device that can be used to measure distance as
well as velocity of an object. An Ultrasonic Sensor works based on the properties of the
sound waves with frequency greater than that of the human audible range.
Using the time of flight of the sound wave, an Ultrasonic Sensor can measure the distance
of the object (similar to SONAR). The Doppler Shift property of the sound wave is used to
measure the velocity of an object.
Top Applications of Sensors
Sensors find usage in various industries like Automotive, Manufacturing, Aviation,
Marine, Medical, Telecom, Chemical, and Computer Hardware. Let’s examine some of the
applications of sensors in these Industries.
1. Automotive
Here are some of the automotive applications of sensors given below:
Braking and Traction control: Antilock Braking System (ABS) Sensors
connected to the wheel, measures the speed of the wheel and braking pressure and
keeps sending them to ABS controlling When the driver applies the sudden brake,
ABS system, with breaking pressure and speed data received from the sensors,
releases the braking pressure to avoid skidding/locking of wheels. It is one of the
critical safety aspects of vehicles.
•
Air Bags – Anti Cushion Restraint System (ACRS): Crush sensors and
accelerometers placed in the vehicle measures the force and sends it to During
accidents on sensing the force exceeds the limit, ACRS will activate the Airbag and
save the life of passengers.
•
Avoiding Collisions: Proximity sensors in the front, back, and sides of the
vehicle forewarn the driver of a possible Infrared, Video assistance, Ultrasonic
technologies assist drivers while parking their vehicles.
•
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Comfort and Convenience: Many sensors provide inputs and warnings to
drivers on Vehicle Speed, Engine Speed, Fuel level, Tire pressure, Door/deck, light
bulbs for driving comfort and convenience.
•
Engine Data: Sensors provides so much data on Engine performance, such
as Ignition, b. Combustion, c. Exhaust gas oxygen, d. Fuel mix, e. Exhaust gas
recycling, f. Transmission control etc.,
•
2. Manufacturing
Here are some of the manufacturing applications of sensors given below:
Predictive maintenance of the machinery, Assembly equipment using the data
collected from sensors in the machines.
•
Optimal utilization of Machines by continuously monitoring the performances
and effectively rejigging the operations with the data collected from sensors.
•
Fine-tuning the Quality systems and enhance the quality standards using the
data collected from sensors. Design notifications and alerts in case of a deterioration
of quality and process standards.
•
Agility in reacting to market demands.
•
3. Aviation
Sensors deployed in the aviation industry measures the data during navigation of aircraft,
monitoring various systems, and controlling instruments. These data are utilized inefficient
flight operations, improve aircraft performance and design improvements.
Some of the instrumentation sensors are tachometers, gauges to measure engine pressure
and oil& fuel quantity, Altimeters, airspeed meters, etc. Sensors help measure the testing
of the ground conditions, vibration and environment factors and provide useful inputs to
the pilot to manage the general operation and emergency conditions.
4. Medical & Healthcare
Signals generated by Sensors in Medical equipment, surgical instruments and devices are
used for diagnosis, treatment and control functions by Doctors. Some of the applications
are:
1.
Blood pressure monitoring (self).
2.
Continuous glucose monitoring by Individuals.
3.
Automatic measurement of vitals of the patient and sending it to the patient’s
doctor.
4.
More home care facilities and ambulatory treatments.
5.
Automatic detection of visitors spreading the disease to patients in hospitals.
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6.
7.
Decentralized laboratories.
Robotics in Operation Theater.
5. Marine
Sensors in ship measures fuel tank levels, liquid cargo levels, tank pressure/temperature.
Pitch, roll, speed and other vessel moments are also measured and monitored with sensors’
help. There are a lot of sensors in Engines measuring typical attributes of internal
combustion parameters.
Conclusion
Industries is taking the usage of sensors’ applications to the next level. Vehicles are tracked
when they are on the move, and their health is monitored using the data generated by
sensors, and in extreme situations, corrective action is taken from a central location. The
data generated by sensors and collected in the database through the sensor application
presents a valuable asset to the organization, and people contemplate monetizing data by
selling it to the stakeholders.
1
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Bibliography
Gesser, H. D. (2002). Applied Chemistry A textbook for engineers and technologists.
Canada: Springer New York.
Gesser, H. D. (n.d.). Applied Chemistry !@#$%^&*()_.
Stocchi, E. (1990). Industrial Chemistry. Holland: HarperCollins.