CALL BELL WITH WELCOME INDICATION

SUBMITTEB BY:-SUBMITTED TO:-

SUNIL BAINS (E092117) TANVIR KAUR (E092120) UJJWAL SAREEN (E092122) VIMMI (E092125) GURPINDER SINGH

GHUMAN (E092136)

Mr. RAJVIR SINGH

INTRODUCTION

It is a simple call bell circuit that displays a welcome message when someone presses the call bell switch momentarily.

The circuit is built around two 555 ICs, seven common anode seven Segment displays and a few discrete components

For better understanding, the whole circuit is divided into two parts controller and display.

The controller section is built around ICS and display section is built around 7segment displays.

 

BLOCK DIAGRAM

CIRCUIT DIAGRAM

LIST OF COMPONENTS

COMPONENTS AMOUNT PRICE(Rs.)

Ic 555 timer 2 40

Switch(push to on\off) 2 2

Led’s 1 1

Capacitors(0.001uf,4.7uf,100uf)

2,1,1 10

Transistors(BC 547) 2 20

Buzzer 1 25

Resistances(330ohm,1Kohm,10Kohm,1Mohm)

2,1,1,2 5

Battery 9V 15

7-Segment Display 7 105

PCB plate 1 30

TOTAL=253

WORKING

The circuit is powered by 6V battery. Power-on the circuit using switch S2. LED1 glows to indicate presence of

power supply in the circuit. Now if you press call bell switch S1 momentarily, it triggers both the

timers (IC1 and IC2) simultaneously, IC1 produces high output at pin 3 for about 5 seconds.

Transistor t2 conducts and piezobuzzer PZ1 sounds for about 5 seconds indicating that there is someone at the door.

At the same time IC2 has high output at pin 3 for about 2 minutes. Transistor t1 conducts to enable the seven segment display to display

WELCOME. If switch S1 is pressed again within five seconds , piezobuzzer

sounds again for 5 seconds and the display continuous to display

WELCOME.

PHOTOS OF WORKING PROJECT

PRECAUTIONS

To avoid any shorting during rain, waterproof the entire circuit assembly including 7-segment display(installed at entrance) by covering it properly.