temperature based fan controller

TEMPERATURE BASED FAN CONTROLLER

BY-

RICHA NIVEDITA

OBJECTIVE OF PROJECT

Our object of making this project is for reducing the power consumption. And also to assist people who are disabled and are unable to control the speed of fan.

It may also be used for monitoring changes in environment.

In near future, it can also be used in different industries and electronic devices.

Introduction A simple introduction about the temperature controller circuit.  This circuit project is mainly used for indicating temperature , controlling temperature.  Microprocessor forms the processing part.

In temperature controller circuit, there are two parts consisting of ◦ ADC 0804 interface with AT89C52.◦ LCD interface with AT89C52

The hardware circuit of temperature controller need the programming.

• There are two possibilities of programming :-

assembly language programming

c language Programming is usually loaded in the AT 89C52 controller IC.

AT89C52 is a family of 8051.

The main principle of this project to indicate temperature and to control the temperature.

COMPONENTS USED:- Microcontroller AT89C51 Resistor Capacitor DC power supply LED Switch Transistor Buzzer Relay Crystal Oscillator ADC0804 Voltage Regulator Temperature Sensor LM 35 LCD Display Socket Diode Electric Fan 12V Opt Coupler ILD74

COMPONENTS USED :- 1. MICROCONTROLLER AT89C51:-

AT89C51 is an 8-bit microcontroller.

  ATMEL 89C51 has 4KB of Flash programmable and

erasable read only memory (EPROM)

It has 128 bytes of RAM.

8 bit microcontroller, means it can read, write and process 8 bit data.

Basically 8 bit specifies the size of data bus. 8 bit microcontroller means 8 bit data can travel on the data bus.

RESISTOR:-

A resistor is a two-terminal electronic component that produces a voltage across its terminals that is proportional to the electric current through it in accordance with Ohm's law:

V = IR

The primary characteristics of a resistor are the resistance, the tolerance, maximum working voltage and the power rating. Other characteristics include temperature coefficient, noise, and inductance.

CAPACITOR:- The capacitor's function is to store electricity, or electrical energy.

The capacitor is constructed with two electrode plates facing each other, but separated by an insulator.

When DC voltage is applied to the capacitor, an electric charge is stored on each electrode.

While the capacitor is charging up, current flows.

The current will stop flowing when the capacitor has fully charged.

LED:- A light-emitting diode (LED) is an electronic light source.

LEDs are used as indicator lamps in many kinds of electronics and increasingly for lighting.

LEDs are based on the semiconductor diode.

The longer lead is the Anode side and the short one is the Cathode side.

TRANSISTOR:- A transistor is a semiconductor device used to amplify and switch

electronic signals and electrical power.

It is composed of semiconductor material with at least three terminals for connection to an external circuit.

BUZZER :- The buzzer is used for audible indication for valid user and error

situation and alarm mode.

As soon as pin of the micro controller goes high, the buzzer or beeper is an audio signaling device, which may be mechanical.

Typical uses of buzzers and beepers include alarm devices, timers.

RELAY INTERFACE :- A relay is an electrical switch that opens and closes under the

control of another electrical circuit.

The switch is operated by an electromagnet to open or close one or many sets of contacts.

A relay will switch one or more poles, each of whose contacts can be thrown by energizing the coil in three ways:-

a) Normally open

b) Normally closed

c) Change over

ADC:- ADC0804 is an 8 bit successive approximation analogue to digital

converter.

The pin out diagram of ADC0804 is shown in the figure below:

TEMPERATURE SENSOR(LM35):-

The LM35 series are precision integrated-circuit temperature sensors, whose output voltage is linearly proportional to the Celsius (Centigrade) temperature.

The LM35 does not require any external calibration or trimming to provide typical accuracies of ±1⁄4˚Cat room temperature.

LCD DISPLAY INTERFACE

LCD (Liquid Crystal Display) screen is an electronic

display module and find a wide range of applications. A 16x2 LCD display is very basic module and is very

commonly used in various devices and circuits.

A 16x2 LCD means it can display 16 characters per line and

there are 2 such lines. Two registers in use:- command register and data register.

DIODE:- A diode is a semiconductor device which allows current to flow

through it in only one direction.

Although a transistor is also a semiconductor device, it does not operate the way a diode does.

A diode is specifically made to allow current to flow through it in only one direction.

OPTO COUPLER:-

An opt coupler is an electronic component that transfers an electrical signal or voltage from one part of a circuit to another, or from one circuit to another, while electrically isolating the two circuits from each other.

It consists of an infrared emitting LED chip that is optically in-line with a light-sensitive silicon semiconductor chip, all enclosed in the same package.

EEPROM:- EEPROM stands for Electrically Erasable Programmable Read-

Only Memory. It has non-volatile memory used in computers and other electronic

devices to store small amounts of data that must be saved. When larger amounts of static data are to be stored (such as in USB

flash drives) a specific type of EEPROM such as flash memory is more economical than traditional EEPROM devices.

BLOCK DIAGRAM

FLOW CHART

CIRCUIT DIAGRAM

CIRCUIT DESCRIPTION:-

ADC0804 is connected as shown in the circuit diagram. Here the input is taken from a preset, which gives different analog signals to the ADC.

The output pins of the ADC are connected to LEDs.

The control pins of the ADC are connected to the microcontroller AT89C52.

The time taken by the ADC to convert analog data into digital form is dependent on the frequency of clock source.

ADC0804 can be given clock from external source.

It also has an internal clock. To use the internal clock a capacitor and resistor is connected to pin 19 and 4 as shown in the circuit diagram.

The frequency is given by the relation f= 1/ (1.1RC).

The circuit uses a resistance of 10k and a capacitor of 150pF to generate clock for ADC0804.

Vin, which is the input pin, is connected to a preset to provide analog input.

ADVANTAGES:- This project can be used in Home.

This project can be used in Industry.

This will help in saving the energy / electricity.

To monitor the environments that is not comfortable, or possible, for humans to monitor, especially for extended periods of time.

Prevents waste of energy when it’s not hot enough for a fan to be needed.

To assist people who are disabled to adjust the fan speed automatically.

DISADVANTAGES:-

It can only be maintained by technical person. Thus, it becomes difficult to be maintained.

Due to temperature variation, after sometimes its efficiency may decrease.

FUTURE SCOPE:-

We can monitor more parameters like humidity, light and at the same time control them.

We can send this data to a remote location using mobile or internet. 

  We can draw graphs of variations in these parameters using

computer.

  When temperature exceeds the limit, a call will be dialed to the

respective given number by an automatic Dialer system.