CONTENTS

1. INTRODUCTION

2. AC MOTOR

3. WATER PUMP

4. WATER TANK

5. POWER SUPPLY

6. WORKING PRINCIPLE

7. SOLDERING

8. COMPONENTS

a. LED

b. TRANSISTOR(BC148)

c. RESISTANCE

d. PIEZO ELECTRIC BUZZER

9. SCOPE

1. INTRODUCTION

Most of the time we wish to have a water tank level controller circuit to know if the amount of water inside the tank has decreased in order to switch ON the water pump set.

Circuit diagram

AC Motor

As in the DC motor case, a

current is passed through the

coil, generating a torque on the

coil. Since the current is

alternating, the motor will run

smoothly only at the frequency

of the sine wave. It is called a

synchronous motor. More

common is the induction motor,

where electric current is induced

in the rotating coils rather than

supplied to them directly.

One of the drawbacks of this kind of AC motor is the high current which must flow

through the rotating contacts. Sparking and heating at those contacts can waste

energy and shorten the lifetime of the motor. In common AC motors the magnetic

field is produced by an electromagnet powered by the same AC voltage as the

motor coil. The coils which produce the magnetic field are sometimes referred to

as the "stator", while the coils and the solid core which rotates is called the

"armature". In an AC motor the magnetic field is sinusoidally varying, just as the

current in the coil varies.

AC Generator

The turning of a coil in a magnetic field produces motional emfs in both sides of

the coil which add. Since the component of the velocity perpendicular to the

magnetic field changes sinusoidally with the rotation, the generated voltage is

sinusoidal or AC. This process can be described in terms of Faraday's law when

you see that the rotation of the coil continually changes the magnetic flux through

the coil and therefore generates a voltage.

Generator and Motor

A hand-cranked generator can be used to generate voltage to turn a motor. This is

an example of energy conversion from mechanical to electrical energy and then

back to mechanical energy.

Water PumpA centrifugal pump like the one used in your car.

The water pump is a simple centrifugal pump driven by a belt connected to the crankshaft of the engine. The pump circulates fluid whenever the engine is running.

The water pump uses centrifugal force to send fluid to the outside while it spins, causing fluid to be drawn from the center continuously. The inlet to the pump is located near the center so that fluid returning from the radiator hits the pump vanes. The pump vanes fling the fluid to the outside of the pump, where it can enter the engine.

The fluid leaving the pump flows first through the engine block and cylinder head, then into the radiator and finally back to the pump.

The pumping of water is a basic and practical technique, far more practical

than scooping it up with one's hands or lifting it in a hand-held bucket. This

is true whether the water is drawn from a fresh source, moved to a needed

location, purified, or used for irrigation, washing, or sewage treatment, or

for evacuating water from an undesirable location. Regardless of the

outcome, the energy required to pump water is an extremely demanding

component of water consumption. All other processes depend or benefit

either from water descending from a higher elevation or some pressurized

plumbing system.

The ancient concept of the aqueduct took simple and eloquent advantage

of maintaining elevation of water for as long and far a distance as possible.

Thus, as water moves over great distances, it retains a larger component of

its kinetic energy by spending small portions of this energy flowing down a

slight gradation. Granted, a useful aqueduct system ultimately depends on

a fresh water source existing at a higher elevation than the location where

the water can be of use.Gravity does all the work. In all other instances,

pumps are necessary.

In day-to-day situations, available water is often contaminated, unhealthy,

or even naturally poisonous, so that it is necessary to pump potable

water from lower levels to higher levels, where it can be of use. A fresh

water source in a lower stream, river, pond, or lake is often pumped to

higher ground for irrigation, livestock, cooking, cleaning or other uses by

humans, who quite naturally need fresh water. This will purify mostly fresh

water, and the treatment of largely contaminated water refer endlessly to

pumping.

Water tank

A water tank is a container for storing water. The need for a water tank is

as old as civilisation, providing storage of water for drinking

water, irrigation agriculture, fire suppression, agricultural farming, both for

plants and livestock, chemicalmanufacturing, food preparation as well as

many other applications. Water tank parameters include the general design

of the tank, and choice of construction materials. Various materials are

used for making a water

tank: plastics (polyethylene,polypropylene), fiberglass, concrete, stone, ste

el (welded or bolted, carbon, or stainless), Earthen ponds function as water

storage.

Types

Chemical contact tank of FDA and NSF polyethylene construction, allows

for retention time for chemical treatment chemicals to "contact" ( chemically

treat ) with product water. (black tank in foreground)

The taanka is used in Rajasthan as a traditional form of rainwater

harvesting

Ground water tank is made of lined carbon steel, it may receive water

from a water well or from surface water allowing a large volume of water to

be placed in inventory and used during peak demand cycles.

Elevated Water Tank is also known as a water tower, an elevated water

tower will create pressure at the ground-level outlet of 1 psi per 2.31 feet of

elevation, thus a tank elevated to 70 feet creates about 30 psi of discharge

pressure. 30 psi is sufficient for most domestic and industrial requirements.

Vertical cylindrical dome top tanks may hold from fifty gallons to several

million gallons. Horizontal cylindrical tanks are typically used for transport

because their low-profile creates a low center of gravity helping to maintain

equilibrium for the transport vehicle, trailer or truck.

A Hydro-pneumatic tank is typically a horizontal pressurized storage tank.

Pressurizing this reservoir of water creates a surge free delivery of stored

water into the distribution system.

Design

By design a water tank or container should do no harm to the water. Water

is susceptible to a number of ambient negative influences,

including bacteria, viruses, algae, changes in pH, and accumulation

of minerals, accumulated gas. The contamination can come from a variety

of origins including piping, tank construction materials, animal and bird

feces, mineral and gas intrusion. A correctly designed water tank works to

address and mitigate these negative effects.

A safety based news article linked copper poisoning from a plastic tank.

The article indicated that rainwater was collected and stored in a plastic

tank and that the tank did nothing to mitigate the low Ph. The water was

then brought into homes with copper piping, the copper was released by

the high acid rainwater and caused poisoning in humans. It is important to

note that since the plastic tank is an inert container, it has no effect on the

incoming water. Good practice would be to analyze any water source

periodically and treat accordingly, in this case the collected acid rain should

be analyzed, and ph adjusted before being brought into a domestic water

supply system.

The release of copper due to acidic water is monitored may be

accomplished with a variety of technology, beginning with Ph strips and

going to more sophisticated Ph monitors, indicate Ph which when acidic or

caustic, some with output communication capabilities. There is no "linkage"

between the plastic tank and copper poisoning, a solution to the problem is

easy, monitor 'stored rainwater' with 'swimming pool strips' cheap and

available at, swimming pool supply outlets. If the water is too acidic, contact

state/county/local health officials to obtain advice and precise solutions and

ph limits and guidelines as to what should be used to treat rainwater to be

used as domestic drinking water.

Volumes of simple tank geometry may be calculated as follows. Beginning

with the fact that a cubic foot contains 7.48 gallons. A rectangular shaped

tank is calculated at (length) times (width) times (height) times 7.48 gallons

equals volumentric content in US gallons. For a cylinder volume is

calculated at Pi (3.14) times (radius squared) times (height) equals cubic

feet times 7.48 gallons equals volumetric content in US gallons.

Articles and specifications for Water Tank applications and design

considerations, these AWWA details are required in many states to

complete a certification process to insure the quality of water being

consumed.

The American Water Works Association is a reservoir of water tank

knowledge; the association provides specifications for a variety of water

storage tank applications as well as design. The AWWA's site provides

scientific resources with which the reader will be able to develop an

informed perspective on which to make decisions regarding their water tank

requirements

POWER SUPPLY

INTRODUCTION TO POWER SUPPLY:

Power supply is an important part of operation of the microcontroller.

Microcontroller operates at +5V DC and also for other IC’s and displays. A 220v

ac to 12-0-12v transformer is used and for rectification, two diodes IN4007 are

connected for rectification of the step down ac supply. Filter capacitor of 1000uF is

used. It is regulated to +5V using a regulator 7805. 0.1uF capacitor is used for

filtration of high frequency noise. LED is give3n for power on indication.

TRANSFORMER:

Definition:

The transformer is a static electro-magnetic device that transforms one

alternating voltage (current) into another voltage (current). However, power

remains the some during the transformation. Transformers play a major role in the

transmission and distribution of ac power.

Principle:

Transformer works on the principle of mutual induction. A transformer

consists of laminated magnetic core forming the magnetic frame. Primary and

secondary coils are wound upon the two cores of the magnetic frame, linked by the

common magnetic flux. When an alternating voltage is applied across the primary

coil, a current flows in the primary coil producing magnetic flux in the transformer

core. This flux induces voltage in secondary coil.

Transformers are classified as:

Based on position of the windings with respect to core i.e.

Core type transformer

(1) Shell type transformer

(a) Transformation ratio:

(1) Step up transformer

(2) Step down transformer

(a) Core & shell types: Transformer is simplest electrical machine, which

consists of windings on the laminated magnetic core. There are two

possibilities of putting up the windings on the core.

(1) Winding encircle the core in the case of core type transformer

(2) Cores encircle the windings on shell type transformer.

(b) Step up and Step down: In these Voltage transformation takes place

according to whether the

Primary is high voltage coil or a low voltage coil.

(1) Lower to higher-> Step up

(2) Higher to lower-> Step down

LM7805C:

A variable regulated power supply, also called a variable bench power

supply, is one where you can continuously adjust the output voltage to your

requirements. Varying the output of the power supply is the recommended way to

test a project after having double checked parts placement against circuit drawings

and the parts placement guide.

This type of regulation is ideal for having a simple variable bench power

supply. Actually this is quite important because one of the first projects a hobbyist

should undertake is the construction of a variable regulated power supply. While a

dedicated supply is quite handy e.g. 5V or 12V, it's much handier to have a

variable supply on hand, especially for testing.

Most digital logic circuits and processors need a 5 volt power supply. To use

these parts we need to build a regulated 5 volt source. Usually you start with an

unregulated power To make a 5 volt power supply, we use a LM7805 voltage

regulator IC (Integrated Circuit).

The LM7805 is simple to use. You simply connect the positive lead of your

unregulated DC power supply (anything from 9VDC to 24VDC) to the Input pin,

connect the negative lead to the Common pin and then when you turn on the

power, you get a 5 volt supply from the Output pin.

CIRCUIT FEATURES

Brief description of operation: Gives out well regulated +5V output, output

current capability of 100 mA

Circuit protection: Built-in overheating protection shuts down output when

regulator IC gets too hot

Circuit complexity: Very simple and easy to build

Circuit performance: Very stable +5V output voltage, reliable operation

Availability of components: Easy to get, uses only very common basic

components

Design testing: Based on datasheet example circuit, I have used this circuit

successfully as part of many electronics projects

Applications: Part of electronics devices, small laboratory power supply

Power supply voltage: Unregulated DC 8-18V power supply

Power supply current: Needed output current + 5 mA

Component costs: Few dollars for the electronics components + the input

transformer

WORKING PRINCIPLE

The connections and arrangements are made as shown in the figure above. The +9V is supplied to water using a metal contact.  In this circuit all the transistors are working as a switch. When the water touches the metal contact in which base of each transistor is connected, a small current flows and turns on the transistor. When a transistor turns on, LED connected to it glows.  Thus LEDs will be turned on depending up on the level of water. By using a relay we can also control the level of water.

2. BREADBOARD

A breadboard (proto board) is a construction base for a one-of-a-kind electronic circuit, a prototype. In modern times the term is commonly used to refer to a particular type of breadboard, the solder less breadboard (plug board).

Because the solder less breadboard does not require soldering, it is reusable, and thus can be used for temporary prototypes and experimenting with circuit design more easily. Other, often historic, breadboard types don't have this property. This is also in contrast to strip board (veroboard) and similar prototyping printed circuit boards, which are used to build more permanent soldered prototypes or one-offs, and cannot easily be reused.

A modern solder less breadboard consists of a perforated block of plastic with numerous tin plated phosphor bronze or nickel silver alloy[5] spring clips under the perforations. The spacing between the clips (lead pitch) is typically 0.1" (2.54 mm). Integrated circuits (ICs) in dual in-line packages (DIPs) can be inserted to straddle the centerline of the block. Interconnecting wires and the leads of discrete components (such as capacitors, resistors, inductors, etc.) can be inserted into the remaining free holes to complete the circuit. Where ICs are not used, discrete components and connecting wires may use any of the holes. Typically the spring clips are rated for 1 Ampere at 5 Volts and 0.333 Amperes at 15 Volts (5 Watts).

Limitations

An example of a complex circuit built on a breadboard. The circuit is an Intel 8088 single board computer.

.

Due to large stray capacitance (from 2-25pF per contact point), high inductance of some connections and a relatively high and not very reproducible contact resistance, solderless breadboards are limited to operate at relatively low frequencies, usually less than 10 MHz, depending on the nature of the circuit. The relative high contact resistance can already be a problem for DC and very low frequency circuits. Solderless breadboards are further limited by their voltage and current ratings.

Solderless breadboards usually cannot accommodate Surface mount technology devices (SMD) or non 0.1" (2.54 mm) grid spaced components, like for example those with 2 mm spacing. Further, they can not accommodate components with multiple rows of connectors, if these connectors don't match the DIL layout (impossible to provide correct electrical connectivity). Sometimes small PCB adapters (breakout adapters) can be used to fit the component on. Such adapters carry one or more of the non-fitting components and 0.1" (2.54 mm) connectors in DIL layout. The larger of the components are usually plugged into a socket, where the socket was soldered onto such an adapter. The smaller components (e.g. SMD resistors) are usually directly soldered onto such an adapter. The adapter is then plugged into the breadboard via the 0.1" connectors. However, the need to solder the component or socket onto the adapter contradicts the idea of using a solderless breadboard for prototyping in the first place.

Complex circuits can become unmanageable on a breadboard due to the large amount of wiring necessary.

3. SOLDERING

Soldering is a process in which two or more metal 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.

+ +

=

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 is nearly 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.

4. COMPONENTS

a. 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 work by the effect of electroluminescence, discovered by accident in 1907. The LED was introduced as a practical electronic component in 1962. All early devices emitted low-intensity red light, but modern LEDs are available across the visible, ultraviolet and infra red wavelengths, with very high brightness.

LEDs are based on the semiconductor diode. When the diode is forward biased (switched on), electrons are able to recombine with holes and energy is released in the form of light. This effect is called electroluminescence and the color of the light is determined by the energy gap of the semiconductor. The LED is usually small in area (less than 1 mm2) with integrated optical components to shape its radiation pattern and assist in reflection.

LEDs present many advantages over traditional light sources including lower energy consumption, longer lifetime, improved robustness, smaller size and faster switching. However, they are relatively expensive and require more precise current and heat management than traditional light sources. Applications of LEDs are diverse. They are used as low-energy indicators but also for replacements for traditional light sources in general lighting, automotive lighting and traffic signals. The compact size of LEDs has allowed new text and video displays and sensors to

be developed, while their high switching rates are useful in communications technology.

I-V diagram for a diode an LED will begin to emit light when the on-voltage is exceeded. Typical on voltages are 2-3 Volt

b. TRANSISTOR(BC148)

A transistor is a semiconductor device commonly used to amplify or switch electronic signals. A transistor is made of a solid piece of a semiconductor material, with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals changes the current flowing through another pair of terminals. Because the controlled (output) power can be much more than the controlling (input) power, the transistor provides amplification of a signal. Some transistors are packaged individually but most are found in integrated circuits. The transistor is the fundamental building block of modern electronic devices, and its presence is ubiquitous in modern electronic systems.

Fig: BJT used as an electronic switch, in grounded-emitter configuration.

Transistors are commonly used as electronic switches, for both high power applications including switched-mode power supplies and low power applications such as logic gates.In a grounded-emitter transistor circuit, such as the light-switch circuit shown, as the base voltage rises the base and collector current rise exponentially, and the collector voltage drops because of the collector load resistor. The relevant equations:

VRC = ICE × RC, the voltage across the load (the lamp with resistance RC)VRC + VCE = VCC, the supply voltage shown as 6V

If VCE could fall to 0 (perfect closed switch) then Ic could go no higher than VCC / RC, even with higher base voltage and current. The transistor is then said to be saturated. Hence, values of input voltage can be chosen such that the output is either completely off, or completely on. The transistor is acting as a switch, and

this type of operation is common in digital circuits where only "on" and "off" values are relevant.

c. RESISTANCE

The electrical resistance of an object is a measure of its opposition to the passage of a steady electric current. An object of uniform cross section will have a resistance proportional to its length and inversely proportional to its cross-sectional area, and proportional to the resistivity of the material. Discovered by Georg Ohm in the late 1820s, electrical resistance shares some conceptual parallels with the mechanical notion of friction. The SI unit of electrical resistance is the ohm, symbol Ω. Resistance's reciprocal quantity is electrical conductance measured in Siemens, symbol S. The resistance of a resistive object determines the amount of current through the object for a given potential difference across the object, in accordance with Ohm's law:

WhereR is the resistance of the object, measured in ohms, equivalent to J·s/C2

V is the potential difference across the object, measured in voltsI is the current through the object, measured in amperes.

For a wide variety of materials and conditions, the electrical resistance does not depend on the amount of current through or the amount of voltage across the object, meaning that the resistance R is constant for the given temperature and material. Therefore, the resistance of an object can be defined as the ratio of voltage to current:

In the case of nonlinear objects (not purely resistive, or not obeying Ohm's law), this ratio can change as current or voltage changes; the ratio taken at any particular point, the inverse slope of a chord to an I–V curve, is sometimes referred to as a "chordal resistance" or "static resistance".

d. PIEZO ELECTRIC BUZZER

Basically, the sound source of a piezoelectric sound component is a piezoelectric diaphragm. A piezoelectric diaphragm consists of a piezoelectric ceramic plate which has electrodes on both sides and a metal plate (brass or stainless steel, etc.). A piezoelectric ceramic plate is attached to a metal plate with adhesives. Fig. 2 shows the oscillating system of a piezoelectric diaphragm.

Applying D.C. voltage between electrodes of a piezoelectric diaphragm causes mechanical distortion due to the piezoelectric effect. For a misshaped piezoelectric element, the distortion of the piezoelectric element expands in a radial direction. And the piezoelectric diaphragm bends toward the direction shown in Fig.2 (a). The metal plate bonded to the piezoelectric element does not expand. Conversely, when the piezoelectric element shrinks, the piezoelectric diaphragm bends in the direction shown in Fig.2 (b). Thus, when AC voltage is applied across electrodes, the bending shown in Fig.2 (a) and Fig.2 (b) is repeated as shown in Fig.2 (c), producing sound waves in the air.

5. SCOPE

This circuit not only indicates the amount of water present in the overhead 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.

ADVANTAGES:

The circuit is very economical. It can be employed anywhere. It requires less power and easy in handling.

10. REFERENCES

10.1 BOOKS

The 8051 Microcontroller And Embedded Systems Using

Assembly C by Mazidi and Mazidi.

Electronics Devices and Circuits.

10.2 WEBSITES

1. www.alldatasheet.com

2. www.microchip.com

3. www.avrfreaks.net

4. www.basicx.com