Smart sensors technical seminar

 CONTENTS

Abstract - i

List of figures - ii

S.No .Topic name Pg.No

1. INTRODUCTION 1

2. DEFINITION 2

3. SMART SENSOR NETWORKS 2

SIGNIFCANCE OF SENSOR NETWORK 2-3

4. USEFULNESS OF SILICON TECHNOLOGY IN 3

SMART SENSOR

4.1 SIGNAL CONVERSION EFFECTS 3-4

4.2 USEFULNESS OF SILICON TECHNOLOGY IN 4-5

SMART SENSOR

4.3. SUITABLE SILICON PROCESSING CIRCUIT 5

USING SILICON

5. IMPORTANCE AND ADOPTION OF SMART 5

SENSOR

5.1 COST IMPROVEMENT 5

5.2 REDUCED COST OF BULK CABLES AND 6

CONNECTORS

5.3 REMOTE DIAGNOSTICS 6

5.4 ENHANCEMENT OF APPLICATION 6-7

5.5 ENHANCEMENT OF APPLICATION 7

5.6 SYSTEM RELIABILITY 7

5.7 IMPROVEMENT IN CHARACTERISTICS 7

6. GENERAL ARCHITECTURE OF SMART 8

SENSOR

6.1 DESCRIPTION OF SMART SENSOR 9

ARCHITECTURE

7. BLOCK LEVEL DESIGN CONSIDERATIONS 9

FOR SMART SENSOR

7.1 FUNCTIONS WITHIN ELECTRONICS 9-10

7.2 LEVEL OF INTEGRATION 10-11

8. SUMMARY OF DIFFERENT SMART SENSORS 11-17

S.No. Topic Name Page. No

9. A SMARTER WORLD 18

10. ADVANTAGES OF SMART SENSORS 18

11. DISADVANTAGES OF SMART SENSORS 19

12. APPLICATIONS OF SMART SENSORS 19

12. 1WHAT INDUSTRIES DO BENEFIT FROM 19-20

SMART SENSORS

13. CONCLUSION 21

14. REFERENCES 22

I

ABSTRACT

Smart sensors represent the next evolutionary tools for studying the environment. 

The smart environment relies first and foremost on sensory data from the real world. 

Sensory data comes from smart sensors of different modalities in distributed locations. 

Smart sensor systems are capable of prediction, interpretation, communication and 

intelligent interaction with the environment & hence will leverage new fault management 

of devices and control for distributed resources. Tremendous advances in digital signal 

processing and laser capabilities in recent years have enabled many new sensor 

developments, one of these being smart sensors. Fundamental research has already been 

carried out to develop smart sensors to monitor and control robotics, mobile vehicles, 

cooperative autonomous systems, mechatronics and bioengineering systems. Emerging 

sensors and instrumentation technology can be exploited for enhanced research and 

operational capabilities. Such smart information technology manifests the potential for 

varied applications. It is envisioned that concepts of smart sensors and information 

technology can be transferred and applied to numerous system. The implementation of 

large networks of interconnected smart sensors can monitor and control our world. Better 

understanding of smart sensors perform satisfactorily in real-world conditions and can 

help improve efficiency and reliability. A sensor network consisting of a large number of 

smart sensors, enabling the collection, processing analysis and dissemination of valuable 

information gathered in a variety of environments is being implemented quickly .

II

LIST OF FIGURES

Fig

No.

Title Page

No.

i General Architecture of Smart Senosr 8

Ii Thermistor 11

Iii Infrared Sensor 11

Iv Capacitive proximity sensor 12

V Air pressure sensor 13

Vi Water pressure sensor 13

Vii Gas sensor 13

Viii Alcohol sensor 13

Ix Photoelectric smoke sensor 14

X Ionization smoke sensor 14

Xi linear hall-effect accelerometer 15

Xii Piezoelectric accelerometer 15

Xiii Liquid level sensor 15

Xiv Float type level sensor 15

Xv Ultrasonic sensor 16

Xvi passive infrared sensor 16

Xvii Digital gyroscope 17

Xvii

i

Optical gyroscope 17

Xix Ph sensor 17

Xx Water conductivity sensor 17

1

1.INTRODUCTION

The advent of integrated circuits, which became possible because of the 

tremendous progress in semiconductor technology, resulted in the low cost

microprocessor. Thus if it is possible to design a low cost sensor which is silicon based 

then the overall cost of the control system can be reduced .We can have integrated 

sensors which has electronics and the transduction element together on one silicon chip. 

This complete system can be called as system-on-chip .The main aim of integrating the 

electronics and the sensor is to make an intelligent sensor, which can be called as smart 

sensor. Smart sensors then have the ability to make some decision. Physically a smart 

sensor consists of transduction element, signal conditioning electronic and 

controller/processor that support some intelligence in a single package. In this report the 

physical phenomena of conversion to electrical output using silicon sensors, 

characteristics of smart sensors. A general Smart sensors are an extension of traditional 

sensors to those with advanced learning and adaptation capabilities. The system must also 

be re-configurable and perform the necessary data interpretation, fusion of data from 

multiple sensors and the validation of local and remotely collected data.These sensors 

therefore contain embedded processing functionality that provides the computational 

resources to perform complex sensing and actuating tasks along with high level 

applications. The functions of an smart sensor system can be described in terms of 

compensation, information processing, communications and integration. The combination 

of these respective elements allow for the development of these sensors that can operate 

in a multi-modal fashion as well conducting active autonomous sensing.

Compensation is the ability of the system to detect and respond to changes in the network 

environment through self-diagnostic routines, self-calibration and adaptation. A smart sensor 

must be able to evaluate the validity of collected data, compare it with that obtained by other 

sensors and confirm the accuracy

Information processing encompasses the data related processing that aims to enhance and 

interpret the collected data and maximize the efficiency of the system, through signal 

conditioning, data reduction, event detection and decision making.

Communications component of sensor systems incorporates the standardized network protocol 

which serves to links the distributed sensors in a coherent manner, enabling efficient 

communications and fault tolerance.

Integration in smart sensors involves the coupling of sensing and computation at the chip level. 

This can be implemented using micro electro-mechanical systems (MEMS), nano-technology and 

bio-technology.

Validation of sensors is required to avoid the potential disastrous effects of the propagation of 

erroneous data. The incorporation of data validation into smart sensors increases the overall 

reliability of the system

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2. DEFINITION

Smart sensors are sensors with integrated electronics that can perform one or

more of the following function logic functions, two-way communication, make decisions.

A smart sensor is a device that takes input from the physical environment and 

uses built-In compute resources to perform predefined functions upon detection of 

specific input and then process data before passing on it.

3.SMART SENSOR NETWORKS :

Wireless sensor networks are potentially one of the most important technologies 

of this century. A sensor network is an array of sensors of diverse type interconnected by 

a communications network. Sensor data is shared between the sensors and used as input 

to a distributed estimation system which aims to extract as much relevant information 

from the available sensor data. The fundamental objectives for sensor networks are 

reliability, accuracy, flexibility, cost effectiveness and ease of deployment. A sensor 

network is made up of individual multifunctional sensor nodes. The sensor node itself 

may be composed of various elements such as various multi-mode sensing hardware 

(acoustic, seismic, infrared, magnetic, chemical, imagers, microradars), embedded 

processor, memory, power-supply, communications device (wireless and/or wired) and 

location determination capabilities . A sensor network can be described by services, data 

and physical layer respectively.

3.1 SIGNIFICANCE OF SENSOR NETWORK:

 Sensing accuracy: The utilization of a larger number and variety of sensor nodes 

provides potential for greater accuracy in the information gathered as compared to 

that obtained from a single sensor.

 Area coverage: A distributed wireless network will enable the sensor network to 

span a greater geographical area without adverse impact on the overall network 

cost.

 Fault tolerance: Device redundancy and consequently information redundancy can 

be utilized to ensure a level of fault tolerance in individual sensors.

 Connectivity: Multiple sensor networks may be connected through sink nodes, 

along with existing wired networks (eg. Internet).

 Minimal human interaction: The potential for self-organizing and self maintaining 

networks along with highly adaptive network topology significantly reduce the 

need for further human interaction with a network other than the receipt of 

information.

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 Operability in harsh environments: Robust sensor design, integrated with high 

levels of fault tolerance and network reliability enable the deployment ofsensor.

4.USEFULNESS OF SILICON TECHNOLOGY IN SMART SENSOR

There are very convincing advantages of using silicon technology in the 

construction of smart sensor. All integrated circuits employ silicon technology. A smart 

sensor is made with the same technology as integrated circuits. A smart sensor utilizes 

the transduction properties of one class of materials and electronic properties of silicon 

(GaAs). A transduction element either includes thin metal films, zinc oxide and 

polymeric films. Integrating electronics circuits on the sensor chip makes it possible to 

have single chip solution. Integrated sensors provide significant advantages in terms of 

overall size and the ability to use small signals from the transduction element. The IC 

industry will get involved in smart sensor if a very large market can be captured and the 

production of smart sensor does not require non-standard processing steps.

4.1 Signal conversion effects

We know that silicon shows a suitable physical signal conversion effect. Many of 

the physical effects of silicon can be used in making sensors. Based on these effects, 

different types of sensors can be constructed which can be used for measuring different 

physical and chemical measurand.

Table1 below shows how different non electrical signal in which we can classify 

different measurand and Table 2 shows the physical effects for sensors in silicon.

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One problem with silicon is that its sensitivities to strain, light and magnetic field show a 

large crosssensitivity to temperature. When it is not possible to have silicon with proper 

effect, it is possible to deposit layers of materials with desired sensitivity on the top of a 

silicon substrate. Thus we can have a magnetic field sensor by depositing Ni-Fe layer on 

the top of a silicon substrate.

4.2 Different Silicon Sensors Employing Above Effects

Radiant Signal Domain

Silicon can be used to construct a sensor for sensing wide range of radiant signal 

from gamma rays to infrared. Silicon can be used for the fabrication of photoconductors, 

photodiode, and phototransistor or to detect nuclear radiation.

Mechanical Signal Domain

Silicon can be used for measuring force and pressure because of the piezo 

resistance effect. This effect is large because the average mobility of electrons and holes 

in silicon is strongly affected by the application of strain. Silicon can also be used for the 

measurement of air or gas velocities. If we slightly heat a silicon structure having two 

temperature measuring devices, and is brought into airflow then the By photoelectric 

principle one can find angular position by employing resulting a temperature difference is 

proportional to the square root of the flow velocity. Combining a piezo resistor, diffused 

in a cantilevered beam or a piezoelectric layer with silicon can make a miniature 

accelerometer. two photodiodes (i.e. one for X co-ordinate and other for Y)

Thermal Signal Domain

We know that all electron devices in silicon show temperature dependence, this 

property of silicon can be used for the measurement of temperature. This can be achieved 

by using two bipolar transistors with a constant ratio of emitter current. Another way of 

measuring temperature is to integrate thermocouples consisting of evaporated aluminium 

films and diffused p-type and n-type layers. This is possible because Seebeck in silicon is

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very large.

Magnetic Signal Domain

Silicon is a non –magnetic material but it can be used for the construction of Hall 

plates and transistor structures that are sensitive to magnetic fields. These sensors are 

constructed by depositing a thin magnetic Ni-Fe film on top of silicon chip that also 

contains electronic circuits.

Chemical Signal Domain

The demand for the better process control for bio-medical, automotive and 

environmental applications has encouraged many laboratories to undertake silicon 

chemical sensor. The ion-sensitive FET (ISFET) is best suitable for such application. 

When an ISFET with properly chosen ion-sensitive gate insulators is immersed in an 

electrolyte,the change of the drain current is a measure of the concentration of the ions or 

the pH.Chemical sensors can be used as humidity sensor or gas sensor.

4.3 Suitable Silicon Processing Circuit Using Silicon

The silicon sensor can produce output as voltage, current, resistance or 

capacitance, output format can be analog or digital. Suitable signal conditioning circuits 

along with processor can easily designed using silicon technology.

5. Importance and Adoption of Smart Sensor

The presence of controller/processor in smart sensor has led to corrections for 

different undesirable sensor characteristics which include input offset and span variation, 

non-linearity and cross-sensitivity. As these are carried in software, no additional 

hardware is required and thus calibration becomes an electronic process. Thus it is 

possible to calibrate the batches of sensor during production without the need to remove 

the sensor from its current environment or test fixture.

5.1 Cost improvement

In case of smart sensor inside hardware is more complex in the sensor on the other hand 

it is simpler outside the sensor. Thus the cost of the sensor is in its setup, which can be 

reduced by reducing the effort of setup, and by removing repetitive testing.

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5.2 Reduced cost of bulk cables and connectors

Use of smart sensor has significantly reduced the cost of bulk cables and 

connectors needed to connect different blocks (i.e. electronic circuits).

5.3 Remote Diagnostics

Due to the existence of the processor with in the package, it is possible to have 

digital communication via a standard bus and a built in self-test (BIST). This is very 

helpful in production test of integrated circuits. This diagnostic can be a set of rules based 

program running in the sensor.

5.4 Enhancement of application

Smart sensor also enhances the following applications:

 Self calibration

 Computation

 Communication

 Multisensing

Self calibration:

Self-calibration means adjusting some parameter of sensor during fabrication, this 

can be either gain or offset or both. Self-calibration is to adjust the deviation of the output 

of sensor from the desired value when the input is at minimum or it can be an initial 

adjustment of gain. Calibration is needed because their adjustments usually change with 

time that needs the device to be removed and recalibrated. the manufacturer over-designs, 

which ensure that device, will operate within specification during its service life. These 

problems are solved by smart sensor as it has built in microprocessor that has the 

correction functions in its memory

Computation:

Computation also allows one to obtain the average, variance and standard 

deviation for the set of measurements. This can easily be done using smart sensor. 

Computational ability allows to compensate for the environmental changes such as 

temperature and also to correct for changes in offset and gain.

Communication:

Communication is the means of exchanging or conveying information, which can 

be easily accomplished by smart sensor. This is very helpful as sensor can broadcast 

information about its own status and measurement uncertainty.

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Multisensing

Some smart sensor also has ability to measure more than one physical or chemical 

variable simultaneously. A single smart sensor can measure pressure, temperature, 

humidity gas flow, and infrared, chemical reaction surface acoustic vapor etc.

5.5 System Reliability

System reliability is significantly improved due to the utilization of smart sensors. 

One is due to the reduction in system wiring and second is the ability of the sensor to 

diagnose its own faults and their effect.

5.6 Better Signal to Noise Ratio

The electrical output of most of the sensors is very weak and if this transmitted 

through long wires at lot of noise may get coupled. But by employing smart sensor this 

problem can be avoided.

5.7 Improvement in characteristics

Non-linearity:

Many of the sensors show some non-linearity, by using on-chip feedback systems 

or look up tables we can improve linearity.

Cross-sensitivity:

Most of the sensors show an undesirable sensitivity to strain and temperature. 

Incorporating relevant sensing elements and circuits on the same chip can reduce the 

cross-sensitivity.

Offset:

Offset adjustment requires expensive trimming procedures and even this offsets 

tend to drift. This is very well reduced by sensitivity reduction method.

Parameter drift and component values:

These are functions of time. This can be solved by automatic calibration.

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6. GENERAL ARCHITECTURE OF SMART SENSOR:

One can easily propose a general architecture of smart sensor from its definition, 

functions. From the definition of smart sensor it seems that it is similar to a data 

acquisition system, the only difference being the presence of complete system on a single 

silicon chip. In addition to this it has on–chip offset and temperature compensation. A 

general architecture of smart sensor consists of following important components:

Sensing element/transduction element, Amplifier, Sample and hold, Analog 

multiplexer, Analog to digital converter (ADC), Offset and temperature 

compensation, Digital to analog converter (DAC), Memory, Serial communication 

and Processor

The generalized architecture of smart sensor is shown below:

Fig I

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6.1 Description of Smart Sensor Architecture

Architecture of smart sensor is shown. In the architecture shown A1, A2…An and 

S/H1, S/H2…S/Hn are the amplifiers and sample and hold circuit corresponding to 

different sensing element respectively. So as to get a digital form of an analog signal the 

analog signal is periodically sampled (its instantaneous value is acquired by circuit), and 

that constant value is held and is converted into a digital words. Any type of ADC must 

contain or proceeded by, a circuit that holds the voltage at the input to the ADC converter 

constant during the entire conversion time. Conversion times vary widely, from 

nanoseconds (for flash ADCs) to microseconds (successive approximation ADC) to 

hundreds of microseconds (for dual slope integrator AD

Cs). ADC starts conversion when it receives start of conversion signal (SOC) from the 

processor and after conversion is over it gives end of conversion signal to the processor. 

Outputs of all the sample and hold circuits are multiplexed together so that we can use a 

single ADC, which will reduce the cost of the chip. Offset compensation and correction 

comprises of an ADC for measuring a reference voltage and other for the zero. 

Dedicating two channels of the multiplexer and using only one ADC for whole system 

can avoid the addition of ADC for this. This is helpful in offset correction and zero 

compensation of gain due to temperature drifts of acquisition chain. In addition to this 

smart sensor also include internal memory so that we can store the data and program 

required.

7. BLOCK LEVEL DESIGN CONSIDERATIONS FOR SMART 

SENSOR

Design choice of smart sensor depends on the specific application for which the sensor is 

required and also related to specific industry. Normally a smart sensor will utilize inputs 

form one or more sensor elements either to generate an output signal or to generate a 

correction signals which are applied to the primary output. This includes design of 

circuitry to take output of raw sensor elements and generate compensated and linearized 

sensor output.

7.1 Functions within electronics:

The smart sensor contains some or all of the following functions

Sensor Excitation:

Many a times it is required to alter the sensor excitation over the operating range 

of a sensor. An example of this is a silicon wheat stone bridge, where the drive voltage is 

increased with increasing temperature. This is done to compensate for the reduction in 

sensitivity of the piezoresistors with increase in temperature. A drive stage with 

temperature dependence can be used which is control by a microprocessor. This will also 

reduce the calibration time.

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Analogue Input:

Multiplexing of inputs can be done to avoid duplication of circuit. In multiplexing 

inputs of same type and range are switched to a common front end. The outputs of 

sensors are normalized before they are switched and a variable gain stage is included 

after the multiplexer.In addition to this an offset adjustment is also included in the 

common front end. The variable gain stage also offers an additional advantage where the 

input signals are to be sampled by analog to digital converter (ADC) with fixed reference 

points. Under such situation gain can be increased at the lower end to increase the 

sensitivity.

Data Conversion:

In case of smart sensor most of the signal processing is done in digital form. This 

is possible only when we have an ADC along with an anti-aliasing filter. This is because 

most of the sensor output is in the analog form. Choice of ADC depends on the 

resolution, bandwidth and complexity of anti-aliasing filter.

Digital data bus interface:

The controller embedded in the smart sensor supports communications by digital 

data bus. The advantages of this are:

Wiring is reduced considerably

Automatic calibration at production can be simplified.

Monitoring and diagnostic functions:

In many applications self-test is required. This self-test includes connectivity 

checking and long-term offset correction.

Control processor:

To provide greater flexibility and reduced complexity, a control processor can be 

used. Control processor can do digital filtering. Another important point is software 

development. Processor must allow writing codes in higher language as it reduces the 

development time.

7.2 Level of integration:

Though it is possible to integrate smart sensor on a single piece of silicon it is 

unattractive due to cost and performance. Analog processing, digital logic and nonvolatile memory (NVRAM), can all be done on same piece of silicon. But compromise

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must be made that limit the performance of at least one of these functions.

8. SUMMARY OF DIFFERENT SMART SENSORS:

Some of the smart sensors developed at different research institutes are as follow:

o Temperature Sensors

o Proximity Sensor

o Pressure Sensor

o Gas & Smoke Sensor

o Accelerometer Sensors

o Level Sensors

o Image Sensors

o Motion Detection Sensors

o Optical Sensors

o Gyroscope Sensors

Temperature Sensors:

A temperature sensor is an electronic device that measures the temperature of its 

environment and converts the input data into electronic data to record, monitor, or 

signal temperature changes.

fig ii :thermistor fig iii: infraredsensor

There are many different types of temperature sensors. Some temperature sensors 

require direct contact with the physical object that is being monitored (contact 

temperature sensors), while others indirectly measure the temperature of an object (noncontact temperature sensors).

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Temperature sensors are used in automobiles, medical devices, computers, 

cooking appliances, and other types of machinery.

Proximity Sensors:

A proximity sensor is a sensor able to detect the presence of nearby objects 

without any physical contact.

A proximity sensor often emits an electromagnetic field or a beam of electromagnetic 

radiation (infrared, for instance), and looks for changes in the field or return signal. The 

object being sensed is often referred to as the proximity sensor's target. Different 

proximity sensor targets demand different sensors. For example, a capacitive proximity 

sensor or photoelectric sensor might be suitable for a plastic target; an inductive 

proximity sensor always requires a metal target.

fig iv: capacitive proximity sensor

Proximity sensors are also used in machine vibration monitoring to measure the 

variation in distance between a shaft and its support bearing. This is common in large 

steam turbines, compressors, and motors that use sleeve-type bearings.

Pressure Sensors:

A pressure sensor is a device for pressure measurement of gases or liquids. 

Pressure is an expression of the force required to stop a fluid from expanding, and is 

usually stated in terms of force per unit area. A pressure sensor usually acts as 

a transducer; it generates a signal as a function of the pressure imposed. For the purposes 

of this article, such a signal is electrical.

Pressure sensors can vary drastically in technology, design, performance, 

application suitability and cost. A conservative estimate would be that there may be over 

50 technologies and at least 300 companies making pressure sensors worldwide.

There is also a category of pressure sensors that are designed to measure in a 

dynamic mode for capturing very high speed changes in pressure. Example applications 

for this type of sensor would be in the measuring of combustion pressure in an engine 

cylinder or in a gas turbine. These sensors are commonly manufactured out 

of piezoelectric materials such as quartz.

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fig v: (air pressure sensor) fig vi:(water pressure sensor)

Pressure sensors are used for control and monitoring in thousands of everyday 

applications. Pressure sensors can also be used to indirectly measure other variables such 

as fluid/gas flow, speed, water level, and altitude. Pressure sensors can alternatively be 

called pressure transducers, pressure transmitters, pressure senders, pressure 

indicators, piezometers and manometers, among other names.

Gas & Smoke Sensors:

A gas sensor is a device which detects the presence or concentration of gases in 

the atmosphere. Based on the concentration of the gas the sensor produces a 

corresponding potential difference by changing the resistance of the material inside 

the sensor, which can be measured as output voltage.

fig vii: (gas sensor) fig viii:(alcohol sensor)

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They are commonly used to detect toxic or explosive gasses and measure gas 

concentration. Gas sensors are employed in factories and manufacturing facilities to 

identify gas leaks, and to detect smoke and carbon monoxide in homes. Gas sensors vary 

widely in size (portable and fixed), range, and sensing ability.

Smoke sensor:

A smoke detector is an electronic fire-protection device that automatically senses 

the presence of smoke, as a key indication of fire, and sounds a warning to building 

occupants. Commercial and industrial smoke detectors issue a signal to a fire

alarm control panel as part of a building's central fire alarm system.

fig ix: (photoelectric smoke sensor) fig x:( ionization smoke sensor)

A smoke sensor is a device fitted to smoke alarms. A smoke alarm is designed to 

detect the presence of smoke in a home to alert the occupants that a fire has broken out. 

A smoke alarm contains not only a smoke sensor but also a loud audible alarm (85 

decibels on average) to alert people in the home.

Accelerometer Sensors:

An accelerometer is a device that measures the vibration, or acceleration of 

motion of a structure. The force caused by vibration or a change in motion (acceleration) 

causes the mass to "squeeze" the piezoelectric material which produces an electrical 

charge that is proportional to the force exerted upon it.

The basic underlying working principle of an accelerometer is such as a dumped 

mass on a spring. When acceleration is experienced by this device, the mass gets 

displaced till the spring can easily move the mass, with the same rate equal to the 

acceleration it sensed.

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fig xi: (linear hall-effect accelerometer) fig xii:( piezoelectric accelerometer)

Level Sensors:

Level sensors detect the level of liquids and other fluids and fluidized solids, 

including slurries, granular materials, and powders that exhibit an upper free surface. 

Substances that flow become essentially horizontal in their containers (or other physical 

boundaries) because of gravity whereas most bulk solids pile at an angle of repose to a 

peak. The substance to be measured can be inside a container or can be in its natural form 

(e.g., a river or a lake). The level measurement can be either continuous or point values. 

Continuous level sensors measure level within a specified range and determine the exact 

amount of substance in a certain place, while point-level sensors only indicate whether 

the substance is above or below the sensing point. Generally the latter detect levels that 

are excessively high or low.

fig xiii: (liquid level sensor ) fig xiv:( float type level sensor )

There are many physical and application variables that affect the selection of the 

optimal level monitoring method for industrial and commercial processes.[1] The 

selection criteria include the physical: phase (liquid, solid or 

slurry), temperature, pressure or vacuum, chemistry, dielectric

constant of medium, density (specific gravity) of medium, agitation (action), acoustical or 

electrical noise, vibration, mechanical shock, tank or bin size and shape.

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Motion Detection Sensors:

A motion detector is an electrical device that utilizes a sensor to detect nearby 

motion. Such a device is often integrated as a component of a system that automatically 

performs a task or alerts a user of motion in an area. They form a vital component of 

security, automated lighting control, home control, energy efficiency, and other useful 

systems.

fig xv: (ultrasonic sensor) fig xvi:(passive infrared sensor )

A motion sensor uses one or multiple technologies to detect movement in an area. 

When a sensor detects motion, it sends a signal to your security system's control panel, 

which connects to your monitoring center. This alerts you and the monitoring center to a 

potential threat in your home.

Gyroscope Sensor:

A sensor or device which is used to measure the angular rate or angular velocity 

is known as Gyro sensors. The most important application is monitoring the orientation 

of an object.

Gyroscopes based on other operating principles also exist, such as the microchippackaged MEMS gyroscopes found in electronic devices (sometimes called gyrometers), 

solid-state ring lasers, fibre optic gyroscopes, and the extremely sensitive quantum 

gyroscope.

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fig xvii: (digital gyroscope) fig xviii:( optical gyroscope)

A Gyroscope can be understood as a device that is used to maintain a reference 

direction or provide stability in navigation, stabilizers, etc. Similarly, a gyroscope or a 

Gyro sensor is present in your smartphone to sense angular rotational velocity and 

acceleration.

Water Quality Sensors:

Water quality sensors are employed using two main approaches. They are either 

used to directly measure constituents of interest (chemical concentrations, solids, etc.) in 

the water, or to measure surrogates. Surrogates are chemical concentrations or solids that 

may indicate the presence of unanticipated contaminants in the water.

Water quality sensors are used to detect the water quality and Ion monitoring primarily 

in water distribution systems.

fig xix: (ph sensor) fig xx:( water conductivity sensor)

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9.A SMARTER WORLD:

10. ADVANTAGES OF SMART SENSORS:

 Accelerate processes and make them more accurate.

 Collect process and asset data in real time.

 Monitor processes and assets accurately, reliably, and continuously.

 Increase productivity and reduce total cost of ownership.

 Lower energy wastage.

 High Reliability and Performance

 Easy to Design, Use and Maintain

 Can perform self-assessment and self-calibration

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11. DISADVANTAGES OF SMART SENSORS:

 Narrow or limited temperature range. ...

 Short or limited shelf life. ...

 Cross-sensitivity of other gases. ...

 The greater the exposure to the target gas, the shorter the life span.

 Contains both actuators & sensors, so complexity is higher

 Cost of Wired Smart Sensors are higher

 Sensor Calibration has to be managed by an external processor

 Predefined Embedded Functions have to be given during the design

12. APPLICATIONS OF SMART SENSORS:

 Industrial

 Telecommunication

 Biomedical applications

 Defense Applications

 Home Automation

 Finger print recognition

 Smart Dust

12.1 What industries do benefit from smart sensors?

Healthcare

Sensors are vital in making healthcare management seamless. The various benefits 

include,

 Monitoring hand hygiene compliance

 Occupancy monitoring

 Automate temperature and light settings

 Human-centric lighting

Warehouse and Manufacturing

Smart sensors help manufacturing enterprises in improving employee well-being and 

profitable process workflows. The sensors generate relevant information of various kind 

like,

 Historical data for decision making

 Alerts and reminders on maintenance and repairs

 Lighting automation to ensure active environments

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 Improved space utilization

Check how a California based leading environmental and industrial machinery 

manufacturer replaced their primitive in-house system to a smart facility.

Hospitality

Sensors designed for smart hotels enable cost savings, bring in revenue opportunities, and 

drastically improve guest experiences. For instance, thermostats and occupancy sensors 

allow smart energy-management that wisely utilizes energy, besides automating 

temperature controls and light settings. Let’s see some of the other benefits of sensors in 

the hospitality industry.

 Automated guest interactions

 Personalized experience delivery with guest data

 Self-check-in/check-out and automated room entry

 Push-notifications for room service

Offices

Sensor-based technology is changing the way employees interact and work in 

today’s offices. Smart-sensors are behind this transformation, ensuring improved 

productivity and performance. The list goes on!

 Smart lighting for human-centricity

 Smart HVAC systems for automated climate control

 Intelligent conference room and occupancy data

 Indoor way finding and smart-navigation

Home Automation

Today, there’s some sensor for every home function, or there will be one soon. Sensors 

are the backbone of home automation that directs smart devices on when to work and 

how to work.

 Automated device activation

 Mood lighting and temperature controls

 Pre-set routine schedules

 Theft and unauthorized access detection

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13.CONCLUSION

In recent technologies, WSN has got the spotlight on it because of its unbeatable 

potential, significance and wide range of application areas. As wireless sensor technology 

has evolved, it has become possible to predict the future by using Smart environment 

which was not possible in the past. "Smart Sensors" is Wireless Sensor Network’s one 

step further. This paper is mainly focused on the study of smart sensors and their possible 

and existing usage in various fields The future work for Smart Sensors can include but 

not limited to Smart Grid for improved electric power efficiency, Smart Antenna for 

satisfying demands for drastic high data rates for certain users with high quality of 

service, Smart Highways for handling traffic and accident related issues.

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