Report of

Major exam working project

LED WATER LEVEL INDICATOR WITH ALARM

Contents

Introduction Water Level Indicator Circuit Diagram

Components used in leveller Components description Assembling the components Levels in indicator How water level indicator circuit works

Water Level Indicator Project Application’s

Introduction:

A water level indicator is used to show the level of water in an over head tank. This keeps the user informed about the water level at all times and avoids the situation of water running out when it is most needed. There are ton of water level indicator circuits on the web. But this one is unique because this water level indicator circuit also has an alarm feature. It not only indicates the amount of water present in the overhead tank but also gives an alarm when the tank is full.

Component used in leveller:

Transistor BC548 { 4 } 220 ohm resistors { 3 } Colour L.E.D { 3 } Buzzer { 1 } 9v battery + battery clip { 1 } P.C.B BORD { 1 }

There are Four parts in this project:-

(i) The Sensor PartIt is generally a fixed support inside the tank having some nuts and bolt with wires coming out.(ii) The Circuit PartIt comprises the brain of the module, where in all the various inputs from the sensors are fed. It is the unit from where you will get all the information of how much of water is in the tank.(iii) The Power Supply It is the part where in you will be converting the A/C voltage to a regulated voltage of 5V to the Circuit.(IV) The Buzzer PartIt is responsible for bringing up the sound when the water level fills up in the tank. It will also be having a speaker or a buzzer to alert.

Water leveller indicator diagram

ASSEMBLING THE COMPONENTS:

Preparing the soldering iron: • Place the soldering iron in its stand and plug in. The iron will take a few minutes to reach its operating temperature of about 400°C. • Dampen the sponge in the stand. • Wait a few minutes for the soldering iron to warm up. You can check if it is ready by trying to melt a little solder on the tip. • Wipe the tip of the iron on the damp sponge. This will clean the tip. Melt a little solder on the tip of the iron.

Soldering the components: • Use the component overlay on the PCB to insert the components and solder them in the following order: 1. Resistors 2. Transistors 3. LED 4. Electric Buzzer

Hold the soldering iron like a pen, near the base of the handle. Touch the soldering iron onto the joint to be made. Make sure it touches both the component lead and the track. • Hold the tip there for a few seconds and feed a little solder onto the joint. It should flow smoothly onto the lead and track to form a volcano shape. Apply the solder to the joint, not the iron. • Remove the solder, then the iron, while keeping the joint still. • After all the components have been soldered, check the soldering closely for any breaks. Inspect your work carefully under a bright light. The solder joints should have a ‘shiny’ look about them. Check that there are no solder this placement, fill the tank at least up to the MDL. • This should cause the loudspeaker to generate an alarm. If this does not happen then check whether the toggle switch is in the ON position or not. If not, change the position of the toggle switch to hear the alarm sound. • When the alarm is generated, it can be silenced by disconnecting the AC supply from the circuitry.

Component description:

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. A voltage or current applied to one pair of the transistor's terminals changes the current through another pair of terminals. Because the controlled (output) power can be higher than the controlling (input) power, a transistor can amplify a signal. Today, some transistors are packaged individually, but many more are found embedded in integrated circuits. Transistor as a switch

Transistors are commonly used as electronic switches, both for high-power applications such as switched mode power supply and for low-power applications such as logic gate.

Transistor as an amplifier

The common-emitter amplifier is designed so that a small change in voltage (Vin) changes the small current through the base of the transistor; the transistor's current amplification combined with the properties of the circuit mean that small swings in Vin produce large changes in Vout .

Resistors A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element. Resistors act to reduce current flow, and, at the same time, act to lower voltage levels within circuits. In electronic circuits resistors are used to limit current flow, to adjust signal levels, bias active elements, terminate transmission lines among other uses. High-power resistors that can dissipate many watts of electrical power as heat may be used as part of motor controls, in power distribution systems, or as test loads for generator. Fixed resistors have resistances that only change slightly with temperature, time or operating voltage. Variable resistors can be

used to adjust circuit elements (such as a volume control or a lamp dimmer), or as sensing devices for heat, light, humidity, force, or chemical activity

COLOUR L.E.DA light-emitting diode (LED) is a two-lead semiconductor light source. It is a p n-junction diode, which emits light when activated. When suitable voltage is applied to the leads, electrons are able to recombine with electro holes within the device, releasing energy in the form of photons. This effect is called called electroluminescence, and the colour of the light (corresponding to the energy of the photon) is determined by the energy band gap of the semiconductor.

Piezoelectric Buzzer:A piezoelectric element may be driven by an oscillating electronic circuit or other audio singles source, driven with a piezoelectric audio amplifier. Sounds commonly used to indicate that a button has been pressed are a click, a ring or a beep.

Battery:

An electric battery is a device consisting of two or more electrochemical cells that convert stored chemical energy into electrical energy. Each cell contains a positive terminal, or cathode, and a negative terminal, or anode. Electrolytes allow ions to move between the electrodes and terminals, which allows current to flow out of the battery to perform work.

The operation of this project is very simple and can be understood easily. In our project “water level indicator” there are 3 main conditions:

1. There is no water available in the source tank.2. Intermediate level i.e. either first level to third level .3. There is ample amount of water available in the source tank.

So let us discuss more about these 3 conditions

CONDITION 1: Water not available

When water is not available in water tank the circuit is not completed and because of this neither led nor buzzer is started .

CONDITION 2: Intermediate levels

Now as the water starts filling in the tank a conductive path is established between the sensing probes and the common probe and the corresponding transistors get sufficient biasing at their base, they starts conducting and now.

The yellow led starts glowing .

CONDITION 3: mid level

When the tank becomes half completed the green led will start glowing .

Condition 4 : full level

When the tank become full completed with water red light will glowing .

Condition 5 : overflowing level

When tht tank become full completed with water buzzer will start .

How circuit works:

When the water is empty the wires in the tank are open circuited and the 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 LEDs 2 , 3 and 3 light up gradually.

When the water is full, the base of the transistor B548 is pulled high by the water and this saturates the transistor, turning the buzzer ON. The SPST switch has to be opened to turn the buzzer OFF.

Since it uses CMOS switches the current flowing through the wires is very less and hence the corrosion of electrodes is very minimum.

Remember to turn the switch ON while pumping water otherwise the buzzer will not sound