Why we learn about Sensors?
What are the selection criteria for Sensors?
Types of Sensors
Drawbacks of Sensors
Why we switch to Smart Sensors?
Typical Type of Basic Sensor
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.
4. Why we learn about Sensors?
Electrical engineers need to know about sensors because they produce
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
Mechanical, civil, chemical and bio engineers should be used as sensors to
when they make as different measurements (temperature and other
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.
6. What are the selection criteria for
There are certain features which have to be considered when we choose a sensor.
They are as given below:
Accuracy – should be High
Stability - maintain under abnormal condition
Environmental condition - usually has limits for temperature & humidity
Range - Measurement limit of sensor
Calibration - Essential for most of the measuring devices as the readings changes
Resolution - Smallest increment detected by the sensor
Cost - Should be Low
Power Consumptions - Low
Repeatability - The reading that varies is repeatedly measured under the same
7. Temperature sensors
Ultra sonic sensors
Analog Sound Sensor
Some of the few sensors are mentioned as belows:
Types of Sensors:
9. 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
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
RTDs (Resistance Temperature Detectors), and
10. Proximity Sensor:
This is a type of sensor which can detect the presence of a
nearby object within a given distance, without any
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.
11. Sensor operation:
small prism-shaped sample of single-crystal undoped GaAs attached to ends of
two optical fibers
light energy absorbed by the GaAs crystal depends on temperature
percentage of received vs. transmitted energy is a function of temperature
It can be made small enough for biological implantation
FIBER OPTIC TEMPERATURE SENSOR
Fiber-optic Temperature Sensor
Sensors are used in many industrial and home appliances:
Wireless Sensor Network
Water Level Indicator
Laser Security Alarm
Firing Alarm Sensor
Automatic Braking and Speed Control Mechanism
Smart Phone Touch Screen
Railway Gate Control Mechanism
Fully Automation Control System
13. Drawbacks of Sensors:
Some of the drawbacks occurs in sensors while its in
Life time becomes less due to over usages
Easily affected by external source such as noise, magnetic
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 quantities
More Expensive in RTD sensor than Thermocouples
14. Why we switch to Smart Sensors?
Smart sensor means a sensor with built-in signal processing &
e.g., combining a “dumb sensor” and a microprocessor
A 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 output
Includes self calibration facility
Compensates the environmental changes
15. Typical Smart Sensor:
A Typical Smart Sensor is given as:
SENSOR ADC MICROPROCESSOR
16. 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 Cheap
Low Power Consumptions