Tachometer using AT89S52 microcontroller with motor control

Submitted By:
Ketan Gupta (04211502809)
1
Yatin Jain (04811502809)
Sushil Kumar Mishra (05311502809)
Harshit Jain (05911502809)

RPM METER OR TACHOMETER
 A tachometer
(revolution-counter,
Tach, rev-counter,
RPM gauge) is an
instrument measuring
the rotation speed of a
shaft or disk, as in a
motor or other machine.
The device usually
displays the
revolutions per minute
(RPM) on a calibrated
analogue dial, but digital
displays are increasingly
common.
2

MICROCONTROLLER AND WHY
MICROCONTROLLER NOT
MICROPROCESSOR?
A microcontroller is a single-chip microcomputer which
contains Ram , Rom , Cpu , i/o ports ,Adc and other
peripherals.
 It has fixed amount of Ram , Rom , i/o ports.
It is also called embedded microcontroller because it is
designed for embedded systems performing specific
tasks only.
Microprocessor only has cpu , Alu, stack pointer,
program counter and other registers ,clock timing
circuit.
Microprocessor does not have Ram, Rom and i/o ports
It requires large space and it’s cost is higher as compared 3
to microcontroller.

EMBEDDED SYTEMS
 An embedded system is a
computer system designed for
specific control functions within a
larger system, often with
real-time computing constraints.It is
embedded as part of a complete
device often including hardware and
mechanical parts. By contrast, a
general-purpose computer, such as a
personal computer (PC), is designed
to be flexible and to meet a wide
range of end-user needs. Embedded
systems control many devices in
common use today. 4

WHAT WE ARE DOING ? ? ?
 We , in this project are measuring the RPM of a
motor using an IR sensor.
 The motor speed and direction is made variable
by use of a H-bridge method.
 RPM is shown on LCD display for the two
directions.

5

WHAT WE ARE USING ? ? ?
 We are using an AT89S52 microcontroller for this
project
 A transformer for stepping down the voltage.

 Full wave rectifier for conversion of AC to DC.

 7805 voltage regulator to give a 5v dc voltage.

 An H-bridge to control the direction and speed of
motor.
 Two optocouplers to prevent the microcontroller
from damage by DC 9V fed to the motor.
 LCD showing the RPM with direction.
6

SOFTWARE WE USED ? ? ?
 KEIL programmer IDE

 SPI flash programmer

7

AT89S52

Atmel AT89S52 is a
powerful microcontroller
which provides a highly-
flexible and cost-effective
solution to many embedded
control applications.

It is programmable
compatible with 8051 uc.

8

TOP VIEW OF OUR PROJECT

11

HARDWARE IMPLEMENTATION

 Transformer
 Full wave rectifier
 7805 voltage regulator
 Dc motor
 Direction control through H bridge
 Speed control using PWM
 Speed measurement using IR SENSOR
 Comparator and potentiometer
 optoisolator
 LCD
 Circuit diagram of project
12

TRANSFORMER
 Centre tapped transformer.
 9-0-9v at the output.
 Rating of 1A current.
 It is centre tapped to have both
-ve and +ve half cycle of AC
waveform to contribute to
direct current.
 Transforming energy from
circuit a to b by using mutual
induction.
 TTL logic circuitry can not
work on voltage of 220v so we
are step down it to 9v

13

FULL WAVE RECTIFIER
 Converting both polarities
of input ac voltage to one
of the constant polarity at
its output dc current.
 Yields a higher mean
output voltage .
 Our circuitry can only
work on dc voltage.

14

LM7805-VOLTAGE REGULATOR
 It has 5V Regulated output
voltage.
 Input voltage range:- 5V-18V
 The voltage source in circuit
may have fluctuation and
would not give fixed output
voltage.
 Pin1-input ,Pin2-ground,
Pin3-output
 Heat sink is cooling device by
dissipating heat into
surrounding air to protect
device from damage.
15

SPEED CONTROL USING PWM
 The speed of motor depends on
three factors load , current ,
Voltage.
 By changing the width of pulse
applied to DC motor we can
change the amount of power
delivered to motor, there by
increasing or decreasing the
speed .
 We create various duty cycle
pulses using software.
 Large duty cycle,Higher width
of pulse ,higher mean
voltage,higher power delivered
to motor and higher speed.
 Small duty cycle,Lower width
of pulse,lower mean voltage
,lower speed.
16

SPEED MEASUREMENT USING IR
SENSOR
 DC motor has white and
black surface ,reflecting and
non reflecting respectively.
 IR sensor has emitter (LED)
and collector (photodiode).
 When light strikes black
surface ,PN diode does not
receive photon and when
light strikes white surface
,PN diode receives photon.
 On receiving light from white
surface comparator give
input pulse to uc denoting
one revolution.
 No receive of light from black
surface ,comparator gives low
pulse to uc denoting it is 17
rotating.

DIRECTION CONTROL THROUGH
H BRIDGE

18

HOW ? ? ?
 Transformer steps down 220V to 9-0-9V.
 Full wave rectifier converts the ac into dc.

 7805 voltage regulator regulates the voltage to
5V, which is the operating voltage of our
microcontroller.
 LCD is interfaced with microcontroller.

 IR sensor is used to count the RPM. It consists of
an emitter and a receiver. The second input
terminal of photodiode is connected to a
comparator which is fed to the microcontroller.
 Crystal (12MHz) is used to generate a stable
clock signal for the microcontroller. Duty cycle is
varied so as to change the speed of motor. 21

HOW ? ? ?
 Pin 9 is used as the reset circuit pin.
 Optocoupler is used to prevent damage from 9V
DC as the operating voltage of uc is only 5V.
 LEDS are used to indicate the supply, direction
of rotation of motor & sensing the shiny surface
on motor.
 There’s a shiny patch on motor wheel over which
the reflection takes place everywhere else it
would be absorbed (black)
 Code is burnt on the controller using SPI
programmer.

22

DC MOTOR & IR SENSOR

IR sensor Silvery patch
23
used for
reflection

LCD PICTURES FROM OUR
PROJECT

24

APPLICATIONS
 To measure the rotating speed of disk or shaft.
 To show rate of rotation of engine crankshaft on
cars ,aircrafts and other vehicles.
 To help the drivers in selecting appropriate
throttle and gear settings for the driving
conditions.
 To estimate traffic speed and volume flow in
vehicles.
 In analog audio recording ,it is used to measure
the speed of audiotape.
25

The main limitation of this project is that the IR sensor we are
using for measuring RPM needs to be kept very close (< 1 inch)
to the moving object, hence its practical use can become a bit
limited.

26

The project we have made is less expensive and it can replace
the costly RPM measuring instruments. It can measure the
RPM of any motor without any physical contact with it. It can
also display the rotator speed of any motor with the help of
microcontroller. It can measure the efficiency of any motor and
determine which will be beneficial and better compatible with
our system. It can also check whether any motor is properly
running or not .IR senor needs to be at a very close distance
from the motor, we can make use of a sensor to increase its
range.

27

Any
Queries ? ? ?

28

Tachometer using AT89S52 microcontroller with motor control

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