DIGITAL THERMOMETERDIGITAL THERMOMETER

GROUP MEMBERSGROUP MEMBERS

●SHYAMKUMAR V.SSHYAMKUMAR V.S●VISHNU SUNILKUMARVISHNU SUNILKUMAR●VINEETH V.HVINEETH V.H●VISHNU BABUVISHNU BABU●MOHAMMAD AKBARMOHAMMAD AKBAR

INTRODUCTION

In this project we are presenting a digital thermometer for measuring the atmospheric temperature. LM35 is the temperature sensor used and the measured value is displayed in LCD by interfacing it with PIC microcontroller.

DESIGN AND IMPLEMENTAION

COMPONENTS USED

LM35 temperature sensor.PIC 16F877A.16x2 LCD.Voltage regulator.Crystal oscillator. ResistorsCapacitorsSwitch

CIRCUIT DIAGRAM

COMPONENT DESCRIPTIONCOMPONENT DESCRIPTION

TEMPERATURE SENSOR

LM 35

● Calibrated directly in ˚ Celsius.● Linear + 10.0 mV/˚C scale factor.● 0.5˚C accuracy guaranteeable (at +25˚C)● Rated for full −55˚ to +150˚C range.● Suitable for remote applications.● Operates from 4 to 30 volts.● Less than 60 µA current drain.● Low self-heating, 0.08˚C in still air.

CHARACTERISTICS OF LM 35

VOLTAGE REGULATORIC 7805

IC 7805 is a 5V Voltage Regulator that restricts voltage output to 5V.Maximum input voltage is 35V.Optimal input voltage is 7.2V.

PIC 16F877APIC 16F877APin out diagram

FEATURES OF PIC 16F877AFEATURES OF PIC 16F877A

HIGH PERFOMANCE RISC CPU

●Operating speed:20MHz,200ns instruction cycle.●Operating voltage:4v - 5.5 v●15 interrupt sources.●35 single word instructions

SPECIAL MICROCONTROLLERSPECIAL MICROCONTROLLER FEATURESFEATURES

●Flash memory:14.3 KB(8192 words)●Data SRAM :368 bytes●Data EEPROM 256 bytes

PERIPHERAL FEATURESPERIPHERAL FEATURES

●33 I/O pins: 5 I/O ports●USART/SCI with 9 bit address detection●Timer 0 :8 bit timer/counter with 8 bit prescaler●Timer 1 :16 bit timer/counter with prescaler●Timer 2 :8 bit timer/counter with 8 bit period register,prescaler and postscaler

ANALOG FEATURESANALOG FEATURES

●10 bit,8 channel A/D convertor ●Brown out reset●Analog comparable module

INTERFACING OF PIC 16F877A AND 16x2 LCD

PROGRAMPROGRAM

PORTA=0;TRISA=0X01;PORTB=0;TRISB=0;

HOW IT WORKS...?HOW IT WORKS...?

●The regulated 5V dc supply is given to the PIC using 7805 voltage regulator.●The temperature sensor LM35 produces an analog voltage corresponding to the temperature sensed by it.●The analog voltage is converted into digital form by the PIC 16F877A.●The digital output is displayed on 16x2 LCD by interfacing it with PIC 16F877A.●The digital output is the required temperature in degree celsius.

CIRCUIT SIMULATION USING PROTEUS

APPLICATIONSAPPLICATIONS

●Speed control of fan.●Industrial applications.●Applications in amplifiers.●Laptop cooling.●Application in farm.

CONCLUSIONCONCLUSION

In summary, the micro controller based thermometer is a In summary, the micro controller based thermometer is a device that measures the current atmospheric temperature. It device that measures the current atmospheric temperature. It has been successfully demonstrated that, this will serve as a has been successfully demonstrated that, this will serve as a device for finding out the temperature and displays it on LCD.device for finding out the temperature and displays it on LCD. In this world of global warming the temperature In this world of global warming the temperature measurement has an inevitable role, hence conclusion is made measurement has an inevitable role, hence conclusion is made that this is a successful undertaking.that this is a successful undertaking.

ReferencesReferences

●Mazidi and Mazidi-8051,PIC & Embedded system using assembly language programming

●www.electronics-project-design.com

ACKNOWLEDGEMENTACKNOWLEDGEMENT

We extend our heartfelt gratitude to Miss. We extend our heartfelt gratitude to Miss. Remyamol and Miss. Binu for their valuable Remyamol and Miss. Binu for their valuable

guidance in our project.guidance in our project.

THANK YOUTHANK YOU