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1. SHWETA JINDAL
B.tech3rd year (EI)
BTBTN12410
Roll no. - 7733

2. INTRODUCTION
TYPES OF PROXIMITY SENSOR
CONSTRUCTION
WORKING
APPLICATIONS
ADVANTAGE
DISADVANTAGE
CONCLUSION
REFRENCES

3. A Proximity Sensor Detects An Object When The
Object Approaches Within The Detection Range And
Boundary Of The Sensor.
Proximity Sensor Includes All The Sensor That Perform
Non Contact Detection In Comparison To Sensors Such
As Limit Switch ,That Detect The Object By Physically
Contacting Them.

4.  INDUCTIVE PROXIMITY SENSOR
 CAPACITIVE PROXIMITY SENSOR
 ULTRASONIC PROXIMITY SENSOR
 OPTICAL PROXIMITY SENSOR

5.  An Inductive proximity sensor is an electronic
proximity sensor , which detect metallic object
without touching them.
 Their operating principle is based on a coil and
high frequency oscillator that creates a field in
the close surrounding of the sensing surface .
 The operating distance of the sensor depends on
the coil’s size as well as the target ‘s shape, size
and material

6.  The Main Components Of The Inductive Proximity
Sensor Are. Coil, Oscillator, Detector And The Output
Circuit
 The Operating Distance Of The Sensor Depends On
The Actuator's Shape And Size And Is Strictly Linked
To The Nature Of The Material
 The Coil Generates The High Frequency Magnetic
Field In Front Of The Face. When The Metallic Target
Comes In This Magnetic Field It Absorbs Some Of The
Energy

7.  Hence the oscillator field is affected. The rise or
fall of such oscillation is identified by a threshold
circuit..that changes the output of the sensor.

8. ADVANTAGES
 they are very accurate compared to other
technologies.
 Have high switching rate.
 Can work in harsh environmental conditions.
DISADVANTAGES
 It can detect only metallic target.
 Operating range may be limited.

10.  Capacitive Sensor Are Used For Non Contact
Detection Of Metallic Object And Non Metallic
Object(liquid, Plastic, Wooden Material Etc.)
 Capacitive Proximity Sensors Use The Variation Of
Capacitance Between The Sensor And Object Being
Detected.
 Capacitance Methods Are Very Sensitive ,
Distance Down To One Micro Inch Can Be Measured.

11.  The Main Components Of The Capacitive Proximity
Sensor Are Plate, Oscillator, Threshold Detector And The
Output Circuit.
 The Plate Inside The Sensor Acts As One Plate Of The
Capacitor And The Target Acts As Another Plate And The
Air Acts As The Dielectric Between The Plates.
 The Capacitive Sensor Can Detect Any Targets Whose
Dielectric Constant Is More Than Air

12. Cont..
 As the object comes close to the plate of the
capacitor the capacitance increases and as the
object moves away the capacitance decreases
 an electronic circuit inside the sensor begins to
oscillate. The rise or the fall of such oscillation is
identified by a threshold circuit and based on
that output switches.

13. ADVANTAGES
 It can detect both metallic and non metallic
targets.
 Good stability
 High Speed
 Capacitive sensors are good in terms of power
usage
 Low cost
DISADVANTAGES
 They are affected by temperature and humidity
 Difficulties in designing
 Capacitive proximity sensors are not as accurate
compare to inductive sensors.

15.  The Proximity Of The Object Is Detected By The Action
Of The Travelling Light Move.
 These Sensors Use Light Sensitive Elements To Detect
Objects And Are Made Up Of An Transmitter (Light
Source) And A Receiver
 The Object Within The Range Of The Sensor Can Detect
The Presence.

16.  The Light Emitted By The Transmitter Focuses On The
Object Which Reflects To Be Received By The Receiver
Photo Diode.
 The Reflected Waves Travel Back And Received By The
Solid State Photo Diode, Through The Receiver Lens.

17. ADVANTAGES
 They Are Useful And Can Help Many Security
Problems.
DISADVANTGES
 They Can Easily Be Set Off And Cause Problems.
 They Are Expensive Than Inductive And Capacitive
Proximity Sensor
APPLICATION
 Optical proximity sensors mostly apply in
automobile/process eng. For distance
measurement, level sensing etc.

18.  Ultrasonic Sensor Are Some Type Used In Place
Of Optical Sensors . Instead Of Using An Light
Beam , A High Frequency Sound Wave Is Used.
 This Sound Wave Is Above Normal Hearing
Frequencies And Are Called Ultrasonic
Frequencies Around 40 KHz Are Common.
 The Ultrasonic Sensor Can Measure Distances In
Centimeters And Inches. It Provides Good
Readings In Sensing Large-sized Objects With
Hard Surfaces.

19.  The ultrasonic sensor sends out sound and receives
it back using the receiver. Together, the ultrasonic
sensor's sender and receiver look like a pair of eyes,
but it is not a sight sensor. Instead, those "eyes" are
really more like a speaker and a microphone (a sound
sensor).

21. CONT.
 The Emitter And Detector Are 2 Separate Units. The
Emitter Emits The Light Which Is Detected By The
Detector. A Target Is Detected When It Passes In-between
The Emitter And Detector.

22. ADVANTAGES
 Ultrasonic proximity sensors are not affected
by atmospheric dust, snow, rain..etc
 Can work in adverse conditions
 Sensing distance is more compared to
inductive or capacitive proximity sensors
DISADVANTAGES
 Ultrasonic sensors Has More Difficulties
Reading Reflections From Soft, Curved, Thin
Or Small Objects.

23.  The global market for these proximity sensors is
expected to grow at a steady rate. Major
industries using proximity sensors are machine
tools, woodworking machines, packaging
machines and other types of machinery.
 Further applications of are automatic door units
such as garage doors or doors inside buildings,
elevator doors or doors inside railway coaches.
 The building and automotive sector are further
industries using high volumes of proximity
sensors.

24. http://literature.rockwellautomation.com/idc/groups/l
iterature/documents/ca/c116-ca502_-en-p.pdf
http://en.wikipedia.org/wiki/Proximity_sensor
http://www.fargocontrols.com/sensors.html
http://www.autonics.co.in/products/products_2.php?b
ig=01&mid=01/01
http://www.ia.omron.com/support/guide/41/overview
.html
http://www.sensorcentral.com/photoelectric/proximity
01.php
http://www.engineershandbook.com/Components/pro
ximitysensors.htm