microcontroller based3rd phase project

7/27/2019 Microcontroller Based3rd Phase Project

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MICROCONTROLLER BASEDRPM COUNTER

PRESENTED BY: AKHIL S (03)&

AKHIL R (04)Guided by:


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INTRODUCTION

Counting the revolutions per minute (RPM) of motors,

determining the motor speed.

Essential in the field of industrial automation.

Useful for closed-loop control systems.

Proper action can be taken, actual RPM deviates from the setRPM.


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AIM

Project based on microcontroller AT89C4051 that measuresand shows on an LCD the RPM of a running motor.

Using a proper transducer, first the rotations of the motor are

converted into pulses.

The generated pulses are counted by the microcontroller fora fixed time (say, one second).

The count is multiplied by a factor to get the exact RPM andthen displayed; if time is one second, the factor is 60.


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Block diagram of the RPM counter

based on microcontrollerAT89C4051


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Block Diagram Description

RPM counter based on AT89C4051 microcontroller that generates pulsesfor every rotation of the motor, counts them and shows on the LCD.

On a fixed base,light source on one side and the combination of a light-

dependent resistor (LDR), pulse generator, microcontroller and LCD onthe other side.

Both the arrangements are housed in separate wooden cabinets such thatthe light beam falls directly on the LDR.

The motor is placed on top of the l source. A slotted wheel(optical shaftencoder) is attached to the motor shaft. The wheel is so big that it caninterrupt the light beam falling on the LDR.


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As the motor rotates, the slotted wheel also rotates.

The light beam falls on the LDR whenever the slot aligns with

the light beam and LDR, producing one pulse.

The rotations of the motor are converted into pulses that canbe counted by the program in the microcontroller.

Pulses are counted for one second. The pulse count is

multiplied by 60 (because 1 RPM = 60 RPS) and finally shownon the LCD.


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Circuit of the RPM counter using

AT89C4051


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5 V DC REGULATED POWER SUPPLY

SYSTEM


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Components Required

Semiconductors:

IC1 - AT89C4051 MICROCONTROLLER

IC2 - NE555 TIMER

T1 - 2N2222 npn transistor

D1 - 1N4007 rectifier diode

LED1,LED2 - 5mm LEDLCD - 16x2 line

Resistors (all -watt, 5% carbon):

R1-R4 - 1 kilo-ohm

R5 - 150 ohm

R6 - 220 ohmR7 - 10 kilo-ohm

R8 - 470 ohm

VR1 - 10 kilo ohm preset


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Capacitors :

C1 - 1uf, 16V electrolytic

C2 - 0.01uf ceramic disk

C3,C7 - 0.1uf ceramic diskC4,C5 - 22pf ceramic disk

C6 - 10uf, 16 V electrolytic

C8 - 100uf, 16 V electrolytic

Miscellaneous:S1 - ON\OFF switch

S2 - Push-to-on switch

XTAL - 12MHZ crystal

LDR


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Circuit description

Figure shows the circuit of the RPM meter. It comprises microcontrollerAT89C4051, timer NE555, LCD module (162 line) and a few discrete

components.

Timer NE555 is configured as a monostable multivibrator whose time

period depends upon the combination of resistor R1 and capacitor C1.

Trigger pin 2 of NE555 is pulled high via resistor R2.

The LDR is connected along with resistor R2 to pin 2 of NE555 such that

when the light falls on the LDR, pin 2 goes low to trigger NE555.


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The output from pin 3 of NE555 is inverted by transistor T1 and fed toport pins P3.3 and P3.4 of the microcontroller. LED2 is connected to port

pin P3.0 (pin 2) of the microcontroller.

Data pins D0 through D7 of the LCD are connected to port pins P1.0through P1.7 of the microcontroller, respectively.

Control pins E, RS and R/W of the LCD are connected to port pins P3.2,P3.5 and P3.7, respectively.

A 12MHz crystal connected between pins 4 and 5 of the microcontroller,along with two 22pF capacitors C4 and C5, generates the basic clockfrequency.

Power-on reset is derived with the combination of resistor R7 andcapacitor C6. Switch S2 is used for manual reset.


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WORKING :

1.As the motor starts rotating, the light falls on the LDR when

the slot aligns with the laser beam and LDR.

2. Every time the motor completes one rotation, the

monostable (NE555) triggers to generate one pulse, which isindicated by LED1.

3. As the first pulse arrives, it generates an interrupt for the

microcontroller and immediately the microcontroller startscounting the pulses. This is indicated by LED2.


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4. The microcontroller counts the pulses for a period ofone second. Thereafter, LED2 goes off.

5.The microcontroller stores the count and multiplies itby 60 to give the final RPM count

6. The count is in hex format, so you have to convert itinto decimal first.

7. The decimal values are converted into ASCII andshown on the LCD one by one.


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Circuit TOP


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POWER SUPPLY TOP


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Circuit PCB Layout


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POWER SUPPLY PCB


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SOFTWARE

Software for the RPM counter is written in C

language.

Compiled using Keil Vision3 compiler.

Burned the generated .hex file into the

microcontroller using a suitable programmer.


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FEATURES

Safe and accurate rpm measurements

Consume less power

LCD display gives RPM reading exactly with noguessing or errors


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FUTURE SCOPE

Modern automobile engines & Aircraft

engines

Ultrasonic dental drills

Analogue audio recording & cd players

Turbo chargers

Zippe-type centrifuge used in isotope enrich


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REFERENCES

Electronics For You (EFY)

http://www.electronicsforu.com/electronicsforu/circuitarchives/view_arti

cle.asp?sno=476&id=4690

Muhammad Ali Mazidi, Janice Gillespie Mazidi, The 8051Microcontroller and Embedded Systems, Seventh Edition, Pearson

Education Asia (2004).

Wikipedia

http://en.wikipedia.org/wiki/Tachometer
http://www.electronicsforu.com/electronicsforu/circuitarchives/view_article.asp?sno=476&id=4690http://www.electronicsforu.com/electronicsforu/circuitarchives/view_article.asp?sno=476&id=4690http://www.electronicsforu.com/electronicsforu/circuitarchives/view_article.asp?sno=476&id=4690http://en.wikipedia.org/wiki/Tachometerhttp://en.wikipedia.org/wiki/Tachometerhttp://www.electronicsforu.com/electronicsforu/circuitarchives/view_article.asp?sno=476&id=4690http://www.electronicsforu.com/electronicsforu/circuitarchives/view_article.asp?sno=476&id=4690http://www.electronicsforu.com/electronicsforu/circuitarchives/view_article.asp?sno=476&id=4690


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THANK YOU

microcontroller based3rd phase project

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