IERT allahabad

1. PRADEEP
KUMAR
YADAV
INSTITUTE OF ENGINEERING
& RURAL
TECHNOLOGY,
ALLAHABAD
(Department of Electronics &
Instrumentation )

2.  PRADEEP YADAV (1311022040)
Er. RAJESH MISHRA

3.  INTRODUCTION
WORKING PRINCIPLE
PROXIMITY SENSOR
PRINCIPLE OF COUNTING
CIRCUIT DIAGRAM
PROGRAM FOR MICROCONTROLLER TO
COUNT PULSE
EXPLANATION OF CIRCUIT
ADVANTAGE OF CONTACTLESS
TACHOMETER

4.  Definition:
 An electrical instrument
used to measure the
speed of a rotating object
with out any physical
contact.
 In general these
tachometers can
measure through a
distance of 1m
 Components :
 Wheel coloured as
required
 Micro
controller(at89c52)
 IR sensor
 Motor
 Battery
 LCD screen
 Conducting wires

5.  The main thing in tachometer is counting,which is done by
microcontroller.
 MICRO CONTROLLER:
Micro controller is a type of CPU which is used on the circuits
and contains RAM input and output
 PARTS OF MICROCONTROLLER

6.  A sensor which detects some things near by with out any
physical contact is called proximity sensor
 IR sensor is nothing but an diode in which the diode produces
a small current when the light falls on it
 These currents are very small to detect so we use operation
amplifier to detect the small voltage changes.
 Transistor amplifies the current.

10.  First the program is written to set up the counter
and stater to be at zero as soon as we start
 EA = 1; // be used in in the tachometer
 ET0 = 1; //set the Timer/counter 0
 TR0 = 1; //Enable Timer/counter 0 to count
 TMOD = 0X25; //counter 0 in mode 1 (16 bit counter),
 //timer 1 in mode 2 (auto reload from TH1)
 TH1 = 0; //start counter from 0
 ET1 = 1; //enable timer 1
 TR1 = 1; //Enable Timer/counter 1 to count
 PT0 = 1; //Setup the priorities of timer 1 and timer 0, a 0 gives a
 PT1 = 0; //higher priority.
 Storing the counting number and calculating it per min.

11.  LCD is connected through some resistors to the
ports of the micro controllers.
 The LED’s and LCD’s are always connected
through the resistor. They are very sensitive to
the high voltages(at max 5 volts).
 The wire connection P1, which is connected to
the output of the sensor, is connected to the pin
3.4 of the microcontroller, this pin has a dual
function which is to count incoming pulses and
increment a 8, 13, or 16 bit register according to
the configuration of the timer T0.

12.  The idea behind most digital counting device,
frequency meters and tachometers, is a micro-
controller, used to count the pulses coming from a
sensor or any other electronic device. In the case of
this tachometer, the counted pulses will come from
proximity sensor, which will detect any reflective
element passing in front of it, and thus, will give an
output pulse for each and every rotation of the shaft.
 Those pulses will be fed to the microcontroller and
counted. to understand the microcontroller counts
pulses and deduce the frequency of those pulses.

13.  The current design is an Embedded application which is used
to calculate the speed of the motor without the need of
tachometer. In this application IR frequencies are used to
calculate the speed of the motor.
 It gives better performance and reliability.
 Light in weight as compared to the conventional tachometer.
 Compact in size.
 It is portable so we can carry it to large rotating machine to
note the r.p.m