Temperature based speed control of fan using microcontroller

TEMPERATURE BASED SPEED CONTROL OF FAN

ELECTRONICS & COMMUNICATION PROJECT

GUIDED BY :-SUMAN SWAMI

PREPARED BY :-SUCHITRA [10EEBEC081]SUMAN SIDH [10EEBEC083]

INTRODUCTION

In this project we are using LM35 series analog temperature sensor. This is a precision integrated circuit, whose output voltage is linearly proportional to the Celsius (Centigrade) temperature. It is rated to operate over a -55 degree to + 150 degree Celsius temperature range. It has +10.0mV/Celsius linear scale factor. The output of this sensor will be connected to ATMEGA-32 Micro-controller ‘s PORT-A. The inbuilt ADC in ATMEGA is used for converting into Digital format. That will be used by ATMEGA to generate control logic. Then the PWM output from ATMEGA micro-controller is given to variable speed DC motor through a motor driver stage.

COMPONENTS

1) LM35(TEMPERATURE SENSOR)

2) ATMEGA32 micro-controller unit

A micro-controller contains (in one chip) the following elements :1) Instruction set2) RAM3) ROM, PROM or EPROM4) I/O ports5) Clock generator6) Reset function7) Watching timer8) Serial port9) Interrupts10)Timers11)Analog-to-Digital converters12)Digital-to-Analog converters

3) Brushless variable speed DC Motor [DR-6634-514]

4) N-MOSFET (BUK9575-100A)

5) Resistors (10k ohm, 1k ohm)

6) LM7805 Voltage regulator IC

7) Diodes(1N914)

8) Breadboard

9) Capacitors(0.1 ) & Red LED

PULSE WIDTH MODULATION

The expression of duty cycle is determined by :

METHODOLOGY

Control Algorithm Flow Chart

Hardware Implementation

Block Diagram

Software Implementation

Main steps involved in the program: Initialization of the port A for analog input from sensor Initialization of LCD module foe displaying temperature Initialization of the PWM module Initialization of the TIMER 1

APPLICATION

Personal computers Exhaust fans in large hotels Washing machines CD and DVD players

THANK YOU