muhammad jawhar

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Sensor Applications(Measuring cycle of a motor
by using sensor)
StudentName: Muhammad jawhar
Class: 4 Stage – Group:A1
CourseTitle: Control Lab.
Department: Mechanical and Mechatronics Engineering
College of Engineering
Salahaddin University-Erbil
Academic Year 2020-2021

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Introduction
We live in a World of Sensors. You can find different types of Sensors in our
homes, offices, cars etc. working to make our lives easier by turning on the
lights by detecting our presence, adjusting the room temperature, detect smoke
or fire, make us delicious coffee, open garage doors as soonas our car is near the
doorand many other tasks.
All these and many other automation tasks are possible because of Sensors.
Before going in to the details of What is a Sensor, What are the Different Types
of Sensors and Applications of these different types of Sensors, we will first take
a look at a simple example of an automated system, which is possible because of
Sensors (and many other components as well).
What is a Sensor?
There are numerous definitions as to what a sensoris but I would like to define a
Sensor as an input device which provides an output (signal) with respect to a
specific physical quantity (input).
The term “input device” in the definition of a Sensormeans that it is part of a
bigger system which provides input to a main control system (like a Processoror
a Microcontroller).

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Another unique definition of a Sensoris as follows: It is a device that converts
signals from one energy domain to electrical domain. The definition of the
Sensor can be better understood if we take an example in to consideration
Types of Sensors
1. Temperature Sensor
2. Proximity Sensor
3. Accelerometer
4. IR Sensor (Infrared Sensor)
5. Pressure Sensor
6. Light Sensor
7. Ultrasonic Sensor
8. Smoke, Gas and Alcohol Sensor
9. TouchSensor
10.Color Sensor
11.Humidity Sensor
12.Position Sensor
13.Magnetic Sensor (Hall Effect Sensor)
14.Microphone (Sound Sensor)
15.Tilt Sensor
16.Flow and Level Sensor
17.PIR Sensor
18.TouchSensor
19.Strain and Weight Sensor
Proximity Sensors
A Proximity Sensoris a non-contact type sensorthat detects the presence of
an object. Proximity Sensors can be implemented using different techniques
like Optical (like Infrared or Laser), Sound (Ultrasonic), Magnetic (Hall
Effect), Capacitive, etc.

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Some of the applications of Proximity Sensors are Mobile 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.
Inductive Proximity Sensors

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How do Inductive Proximity Sensors work?
An alternating current is supplied to the coil, generating an electromagnetic
detection field
When a metal object comes closer into the magnetic field, eddy currents
build-up, and result in coil inductance changes
When coil inductance changes, the circuit that has been continuously
monitoring, will trigger the sensor’s outputswitch
*Note: Even when a target is not present, inductive sensors continue to
oscillate. The switch is only triggered when an object is present.
Common applications:
 Industrial usages
 Production automation machines that count products, producttransfers
 Security usages
 Detection of metal objects, armory, land mines, etc.
Advantages of inductive proximity sensors
 Contactless detection
 Environment adaptability; resistant to common conditions seen in
industrial areas such as dust and dirt
 Capable and versatile in metal sensing
 Considerably cheap when it comes to price
 No moving parts, ensuring a longer service life
Disadvantages of inductive proximity sensors
 Lack in detection range, averaging a max range of up to 80mm
 Can only detect metal objects
 Performance can be affected by external conditions; extreme
temperatures,
 cutting fluids or chemicals

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Capacitive proximity sensors
are contactless sensors that detect both metallic and non-metallic objects,
including liquid, powders, and granular. It operates by detecting a change in
capacitance.
Similarly to inductive sensors, it consists of an oscillator, Schmitt trigger and
output switching circuit. The only difference is it comprises of 2 charging
plates (1 internal, 1 external) for capacitation:
 Internal plate connected to the oscillator
 External plate (sensor electrodes) used as the sensing surface
How do capacitive proximity sensors work?
Capacitive proximity sensorproduces an electrostatic field
When an object (conductive/non-conductive) approaches the sensing area, the
capacitance of both plates increases, resulting in oscillator amplitude gain
The resulted amplitude gain triggers sensor output switch
*Note: Capacitive sensors only oscillate when the target object is present
Common applications:
 Industrial usages

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 Production automation machines that count products, producttransfers
 Filling processes, pipelines, inks, etc.
 Fluid level, composition, and pressure
 Moisture control
 Non-invasive content detection
 Touchapplications
Advantages of Capacitive proximity sensors
 Contactless detection
 A wide array of materials able to be detected
 Able to detect objects through non-metallic walls with its wide sensitivity
band
 Well-suited to be used in an industrial environment
 Contains potentiometer that allows users to adjust sensorsensitivity, such
that only wanted objects will be sensed
 No moving parts, ensuring a longer service life
Disadvantages of Capacitive proximity sensors
 Relative low range, though incremental increase from inductive sensors
 Higher price as compared to inductive sensors
Hall effect sensor
A Hall-effect sensor (or simply Hall sensor) is a device to measure the
magnitude of a magnetic field. Its output voltage is directly proportional to
the magnetic field strength through it.Hall-effect sensors are used for proximity
sensing, positioning, speed detection, and current sensing applications.
Frequently, a Hall sensor is combined with threshold detection, so that it acts as
and is called a switch. Commonly seen in industrial applications such as the
pictured pneumatic cylinder, they are also used in consumer equipment; for
example, some computer printers use them to detect missing paper and open
covers. They can also be used in computer keyboards, an application that
requires ultra-high reliability. Another use of a Hall sensor is in the creation of
MIDI organ pedal-boards, where the movement of a "key" on the pedal-board is

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translated as an on/off switch by Hall sensors.Hall sensors are commonly used to
time the speed of wheels and shafts, such as for internal combustion
engine ignition timing, tachometers and anti-lock braking systems. They are
used in brushless DC electric motors to detect the position of the permanent
magnet. In the pictured wheel with two equally spaced magnets, the voltage
from the sensor peaks twice for each revolution. This arrangement is commonly
used to regulate the speed of disk drives.
Advantages
A Hall-effect sensor may operate as an electronic switch.
 Such a switch costs less than a mechanical switch and is much more reliable.
 It can be operated at higher frequencies than a mechanical switch.
 It does not suffer from contact bounce because a solid-state switch with
hysteresis is used rather than a mechanical contact.

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 It is not affected by environmental contaminants, since the sensor is in a
sealed package. Therefore, it can be used under severe conditions.
In the case of linear sensor (for the magnetic-field-strength measurements), a
Hall-effect sensor:
 can measure a wide range of magnetic fields,
 can measure both sign and amplitude,
 can be flat.
Disadvantages
Hall-effect sensors provide much lower measuring accuracy than fluxgate
magnetometers or magneto resistance-based sensors. Moreover, Hall-effect
sensors drift significantly, requiring compensation.
Conclusion
In this paper a review of position control methods for BLDC motors has
been presented. The fundamentals of various techniques have been introduced,
mainly back-EMF schemes and estimators, as a useful reference for preliminary
investigation of conventional methods. Advances in the position control and
applications were also discussed.
To provide insight in control techniques and their benefits a classification of
existing methods and newer methods were presented with their merits and
drawbacks. From the above discussion, it is obvious that the control for BLDC
motors using position sensors, such as shaft encoders, resolvers or Hall-effect
probes, can be improved by means of the elimination of these sensors to further
reduce cost and increase reliability. Furthermore, sensorless control is the only
choice for some applications where those sensors cannot function reliably due to
harsh environmental conditions and a higher performance is required.