REFERENCESx

[1] DIVYA S, " TEMPERATURE ALARM WITH LIMIT CONTROL," SRI RAMANUJAR ENGINEERING COLLEGE, CHENNAI, 2013.

TEMPERATURE ALARM WITH LIMIT CONTROL

OBJECTIVE:

The objective of this project is to monitor the

temperature of the room and alarm is maintained

when it exceeds the limit.

SCOPE:

This project is very much useful intensive care

unit in hospital to monitor the critical lab

temperature.

BRIEF METHODOLOGY:

This project is designed by following blocks

Temperature sensor

Amplifier

DPM (Digital Panel Meter)

LCD

In this project we monitor the temperature in hospitals

or any where in which the temperature sensor input is given

to the amplifier. The amplifier amplifies the signal and the

amplified analog signal is converted into the digital signal

by the digital panel meter (DPM). Finally we are displaying

the temperature value in the seven segment digital display.

ADVANTAGES:

Low power consumption

Economical

Low cost

Easy to implement

Accuracy

Digital measurements

USES:

This project is very much useful in hospital,

laboratory, any fire alarm, etc…

WORKING:

The circuit sets in default temperature as 34˚c. It uses the

PIC 16f877A microcontroller, where PIC- peripheral

interface controller. The LCD is used to display the

temperature which has 2 lines in 16 characters (each line

has 8 characters). It posses 9v battery for the Piezzo buzzer.

The components are crystal oscillator, regulators, capacitor,

etc…

The LCD (LIQUID CRYSTAL DISPLAY) has two

connections:

Data line – This is connected in the port B.

Control lines – This is connected in the

port E.

The general clock pulse is used in this circuit, where buzzer

is connected to the port C, switch input is connected to the

port D, and sensor is connected to port A (LM35). The

port A also posses ADC (analog to digital converter) for the

LCD sensor.

PIC 16F877A:

PIEZZO BUZZER:

PIN DIAGRAM:

CIRCUIT DIAGRAM:

KEYPAD CIRCUIT:

LM 35

BLOCK DIAGRAM: