Water Level Indicator

1 1

INDEX

INDEX

Sr No.

Sr No. Name of topicName of topic Page noPage no 1

1 Introduction Introduction 11 2

2 Functions Functions of of thethe materials materials 2 2 3 3 Transistor Transistor BC BC 548548   SpecificationSpecification   DatasheetDatasheet 3 3 4 4 WorkingWorking 4-54-5 5

5 Circuit Circuit Diagram Diagram 66 6 6 Scope Scope 77 7 7 Materials Materials 88 8 8 99

2

INTRODUCTION

This circuit not only indicates the amount of water present in

the overhead tank but also gives an alarm when the tank is

full. When the water is empty the wires in the tank are open

circuited and the 220ohm resistors pulls the switch low hence

opening the switch and LEDs are OFF. As the water starts

filling up, first the wire in the tank connected to S1 and the

+supply are shorted by water. This closes the switch S1 and

turns the LED1 ON.As the water continues to fill the tank, the

LEDs2, 3 and 4 lights up gradually. The no. of levels of 

indication can be increased as per your requirement. When the

water is full, the base of the transistor BC548 is pulled high

 by the water and this saturates the transistor, turning the

 buzzer ON.

3

Functions of the materials:

1. Resistors: they limit the current and provide only the required  biasing to the vital parts like transistors.

2. Transistors: they amplify the current to provide right amount of  current to the led's to operate.

3. Diode: it allows the current to pass in one direction only. 4. Led bulbs: to indicate different water levels.

5. Connecting wires: to allow the passage of current.

6. 9v battery: to provide required voltage for the led's and prevent hazards related to current.

4

Transistor BC 548

The BC548 is a general purpose epitaxial silicon NPN bipolar   junction transistor found commonly in European electronic

equipment.

The part number is assigned by Pro Electron, which allows many manufacturers to offer electrically and physically interchangeable  parts under one identification. The BC548 is commonly available in

European Union countries. It is often the first type of bipolar 

transistor young hobbyist’s encounter, and is often featured in circuit diagrams and designs published in hobby electronics magazines.

The pinout for the TO-92 package has pin 1 attached to the collector,  pin 2 connected to the base, and pin 3 connected to the emitter.

SPECIFICATION

Devices registered to this Pro Electron number must have minimum  performance characteristics.

 Breakdown voltage, with base open V_CBO = 30 V  Rated collector current I_C = 100 mA

 Rated total power dissipation P_total = 500 mW

 Transition frequency (gain-bandwidth product) f _t =

5

Working:

Wires of different lengths but of same material are tightened by the nuts. Each wire is connected to a particular led. When water is added in the bucket, the first led to glow is the one whose wire is longest. The second led glows when water makes contact with the second longest wire. When a particular wire makes contact with water it will  be connected to wire “n” through water: establishing a negative

voltage across the base of transistor. This results in the flow of current and hence the led’s glow.

Soldering

items are joined together by melting and flowing a filler metal into the  joint, the filler metal having a relatively low melting point.

Soft soldering

is characterized by the melting point of the filler metal, which is  below 400 °C (752 °F). The filler metal used in the process is called

solder . Soldering is distinguished from brazing by use of a lower melting-temperature filler metal; it is distinguished from welding by the base metals not being melted during the joining  process. In a soldering process, heat is applied to the parts to be  joined, causing the solder to melt and be drawn into the joint by

capillary action and to bond to the materials to be joined by wetting action. After the metal cools, the resulting joints are not as strong as the base metal, but have adequate strength, electrical conductivity, and water-tightness for many uses. Soldering is an ancient technique mentioned in the Bible and there is evidence that it was employed up to 5000 years ago in Mesopotamia

6

Soldering filler materials are available in many different alloys for  differing applications. In electronics assembly, the eutectic alloy of  63% tin and 37% lead (or  60/40, which is almost identical in

 performance to the eutectic) has been the alloy of choice. Other alloys are used for plumbing, mechanical assembly, and other applications. In high-temperature metal joining processes (welding, brazing and soldering), the primary purpose of flux is to prevent oxidation of the  base and filler materials. Tin-lead solder, for example, attaches very

well to copper, but poorly to the various oxides of copper, which form quickly at soldering temperatures. Flux is a substance which isnearly inert at room temperature, but which becomes strongly reducing at elevated temperatures, preventing the formation of metal oxides. Secondarily, flux acts as a wetting agent in the soldering process, reducing the surface tension of the molten solder and causing it to  better wet out the parts to be joined.

7

8

SCOPE

This circuit not only indicates the amount of water present in the over  head tank but also gives an alarm when the tank is full. This worthy device starts ringing as soon as the water tank becomes full. It

helps to check overflow and wastage of water by warning the

customer when the tank is about to brim. The system provides visual water level indication with audio alarms at desired levels. It

also provides automatic control of pumps at a remote location. • Now no need to go on the roof to look the water level.

•It shows the water level in your room like 1/4 tank, 1/2 tank, 3/4 tank  and full tank.

•Alarm starts ringing as soon as tank becomes full. •Suitable for every tank.

9

Materials

10

Bibliography

 50 Electronic Projects, Author: MR A.K MAINI

 Mini & Major Electronics Projects,Author: MR S.A KHAN,

Mahal

 Electronic Devices & Circuits,Author : S. Salivahanans, N

Kumar, Publisher : TATA MCGRAW HIL

 Electronic Devices & Circuits I, Author : J.S. Katre  Electronics Devices & Circuits - II, Author : Katre J. S 

www.philohome.com/sensors/gp2d12/gp2d12-datasheets/bc548.pd

 www.alldatasheet.com/datasheet-pdf/pdf/50731/.../BC548.html?  www.instructables.com/id/Water-Level-Indicator