basic sensors technology
Post on 14-Apr-2017
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PRESENTED BYK.VIVEK KUMAR (EEE)
SENSORS
SENSORSIntroWhy we learn about Sensors?What are the selection criteria for Sensors?Types of SensorsApplicationsDrawbacks of SensorsWhy we switch to Smart Sensors?Conclusion
Physical Quantity Sensor Electrical
Quantity
Typical Type of Basic Sensor
Sensors: Sensors are as an electrical device that consists of components that are used to measure any other physical quantities (temperature, light, pressure, etc.) And its produce electrical signals - usually voltage or current signals, that can be used to determine the values for appropriate physical quantity.
Why we learn about Sensors? Electrical engineers need to know about sensors because they produce
electrical signals. These electric signals are needed to be converted to a digital format. Electrical Engineers should need to know about how to design a sensor for
their fields. Mechanical, civil, chemical and bio engineers should be used as sensors to
when they make as different measurements (temperature and other quantities).
They need to know about them in order to select appropriate sensors to make measurements of many different physical quantities.
Engineers should designs a compact size of sensor and it can be used in various fields of applications.
For Example:Wireless Sensor Network System
What are the selection criteria for Sensors?There are certain features which have to be considered when we choose a sensor. They are as given below: Accuracy – should be HighStability - maintain under abnormal conditionEnvironmental condition - usually has limits for temperature & humidityRange - Measurement limit of sensor Calibration - Essential for most of the measuring devices as the readings changes with timeResolution - Smallest increment detected by the sensorCost - Should be LowPower Consumptions - LowRepeatability - The reading that varies is repeatedly measured under the same environment
Temperature sensorsLight sensorsUltra sonic sensorsPressure sensors IR sensorsBiosensorsMagnetic sensorsAnalog Sound SensorVibration Sensor
Some of the few sensors are mentioned as belows:Types of Sensors:
Water Level Sensor
LDR Sensor
Analog Sound Sensor
Electricity Sensor
Current Sensor
Examples of Sensors:
Temperature sensors: Temperature is the most common of all physical measurements. We
have temperature measurement-and-control units, called thermostats. In our home heating systems, refrigerators, air conditioners, and
ovens. Temperature sensors are used on circuit boards, as part of thermal
tests, in industrial controls, and in room controls such as in calibration labs and data centers.
Though there are many types of temperature sensors, most are passive devices:
Thermocouples RTDs (Resistance Temperature Detectors), and Thermistors(Thermal Resistors)
Proximity Sensor:This is a type of sensor which can detect the presence of a
nearby object within a given distance, without any physical contact.
The working principle of a Proximity sensor is simple. A transmitter transmits an electromagnetic radiation or creates an electrostatic field and a receiver receives and analyzes the return signal for interruptions.
There are different types of Proximity sensors and the researchers will discuss only a few of them which are generally used in robots.
Sensor operation:small prism-shaped sample of single-crystal undoped GaAs attached to ends of two
optical fiberslight energy absorbed by the GaAs crystal depends on temperaturepercentage of received vs. transmitted energy is a function of temperatureIt can be made small enough for biological implantation
FIBER OPTIC TEMPERATURE SENSOR
Fiber-optic Temperature Sensor
Applications:Sensors are used in many industrial and home appliances:Wireless Sensor NetworkWater Level IndicatorLaser Security AlarmFiring Alarm SensorAutomatic Braking and Speed Control MechanismSmart Phone Touch ScreenRailway Gate Control MechanismFully Automation Control System
Drawbacks of Sensors:Some of the drawbacks occurs in sensors while its in
working condition:Life time becomes less due to over usagesEasily affected by external source such as noise, magnetic
interference, etc.Due to noise and any other interference, low Stability &
Sensitivity may leads to system failure.Some sensor may face complexity while contact with
some physical quantitiesMore Expensive in RTD sensor than Thermocouples
Why we switch to Smart Sensors?Smart sensor means a sensor with built-in signal processing &
communicatione.g., combining a “dumb sensor” and a microprocessorA Smart Sensor can be defined as a sensor with signal conditioning
circuitary with an integrated circuit which is considered as a single device.
Mainly Smart Sensors have some advantages than using ordinary sensors.Features of Smart Sensor:Linearize its own outputIncludes self calibration facilityCompensates the environmental changes
Typical Smart Sensor:A Typical Smart Sensor is given as:
SENSOR ADC MICROPROCESSOR
MEMORY
COMPUTERIZED
CONTROL ROOM
INPUTPHYSICAL QUANTITY
ELECTRICAL QUANTITY
Conclusion:Sensors are one of the most useful technology for all and also it is very efficient technology in nowadays. So Engineers should always keep in mind, while designing or creating a new type of sensors or any things, that should be satisfying the followings:
Materials should be avail as CheapSimple
Low CostLow Power Consumptions
High ReliableCompact
QUESTIONS……??????
THANKS TO ALL….!!!
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