• LEDs
    • BUZZER
    • 9V BATTERY



Today we are going to talk about a very useful project that we have taken up. It is called the Water Level Indicator. Nowadays everybody has overhead tank at their homes. But everyone who has a water tank above knows the kind of problems that they face. Firstly there is no system to track the water in the tank. Then there comes a secondary problem that is when their water pump is started they have no idea when it gets filled up and sometimes there are situation where the pump keeps on pumping water to the tank and the water starts spilling out from the tank. There is wastage of energy as well as wastage of water.




A breadboard is used to build and test circuits quickly before finalizing any circuit design. The breadboard has many holes into which circuit components like ICs and resistors can be inserted. The bread board has strips of metal which run underneath the board and connect the holes on the top of the board. The top and bottom rows of holes are connected horizontally while the remaining holes are connected vertically. To use the bread board, the legs of components are placed in the holes. Each set of holes connected by a metal strip underneath forms a node. A node is a point in a circuit where two components are connected. Connections between different components are formed by putting their legs in a common node. The long top and bottom row of holes are usually used for power supply connections. The rest of the circuit is built by placing components and connecting them together with jumper wires.



A light-emitting diode (LED) is a semiconductor device that emits visible light when an electric current passes through it. The light is not particularly bright, but in most LEDs it is monochromatic, occurring at a single wavelength. The output from an LED can range from red (at a wavelength of approximately 700 nanometres) to blue-violet (about 400 nanometres). Benefit of LEDs compared with incandescent and fluorescent illuminating devices, include:
• Low power requirement: Most types can be operated with battery power supplies.
• High efficiency: Most of the power supplied to an LED or IRED is converted into radiation in the desired form, with minimal heat production.
• Long life: When properly installed, an LED or IRED can function for decades.



A transistor is an electronic component used in a circuit to control a large amount of current or voltage with a small amount of voltage or current. It does so by sandwiching one semiconductor between two other semiconductors. Because the current is transferred across a material that normally has high resistance (i.e. a resistor), it was a "transfer-resistor" or transistor. There are essentially two basic types of point-contact transistors, the npn transistor and the pnp transistor, where the n and p stand for negative and positive, respectively. The only difference between the two is the arrangement of bias voltages.

BC 547 Features
• Collector-Emitter Volt (Vceo): 45V
• Collector Current (Ic): 0.1A
• hfe: 110-800 @ 2mA
• Power Dissipation (Ptot): 625mW
• Current-Gain-Bandwidth (ftotal): 300MHz
• Type: NPN



A resistor is an electrical component that limits or regulates the flow of electrical current in an electronic circuit. Resistors can also be used to provide a specific voltage for an active device such as a transistor. The current through a resistor is inversely proportional to its resistance, and directly proportional to the voltage across it. This is the well-known Ohm's Law.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 generators. Resistors may have fixed resistances that only change a little 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.



Here we can add any of the normal buzzers that are readily available in the market and if it is not then we can make ourselves with a simple 555 IC. We have used a simpler buzzer that can hold 1.5-27 V DC only. It is connected with the Red LED on the Breadboard and as soon as water reaches the top of the tank along with the glow of LED, Buzzer also produces a sound as an audio signal.A buzzer is a mechanical, electromechanical, magnetic, electromagnetic, electro-acoustic or piezoelectric audio signalling device. A piezo electric buzzer can be driven by an oscillating electronic circuit or other audio signal source. A click, beep or ring can indicate that a button has been pressed. A buzzer or beeper is a signaling device, usually electronic, typically used in automobiles, household appliances such as a microwave oven, or game shows.It most commonly consists of a number of switches or sensors connected to a control unit that determines if and which button was pushed or a preset time has lapsed, and usually illuminates a light on the appropriate button or control panel, and sounds a warning in the form of a continuous or intermittent buzzing or beeping sound.



It has a rectangular prism shape with rounded edges and a polarized snap connector at the top. This type is commonly used in pocket radios and other small electronic devices. They are also used as backup power to keep the time in certain electronic clocks. This format is commonly available in primary carbon-zinc and alkaline chemistry, in primary lithium iron disulfide, and in rechargeable form in nickel-cadmium, nickel-metal hydride and lithium-ion. Mercury oxide batteries in this form have not been manufactured in many years due to their mercury content.

Most nine-volt alkaline batteries are constructed of six individual 1.5V LR61 cells enclosed in a wrapper.These cells are slightly smaller than LR8D425AAAA cells and can be used in their place for some devices, even though they are 3.5 mm shorter. Carbon-zinc types are made with six flat cells in a stack, enclosed in a moisture-resistant wrapper to prevent drying.




The water starts to get filled in the tank and when the water level in the tank starts to rise up, what happens is that the LEDS that are installed in the tank start to get lighten up, one by one indicating the water level in the tank. And finally when it reaches to its top most LED, it will glow as well as a sound from the unit indicating that the water has filled in the tank and one can be alerted that the tank has been filled up and the water pump has to be switched off saving the electricity bill as well as over flow of water from the tank.

Then as shown in the figure we have given all the LEDs in various colour. Starting from the beginning.

1) GREEN LED— Indicating water is at a very low level in the tank.
2) WHITE LED –Indicating half of the tank is filled now.
3) RED LED—Indicating tank is almost full.

There will be no glow when the tank is empty. We need to turn the pump on and as soon as the water starts to rise up the LEDs start to get in contact with the water and the bc547 transistors are activated and there is a flow of current in the transistors making the LEDs light up. Here in between the transistors and the LEDs there are current limiting resistors of 330 ohms, the job of the resistor is to check that the LED does not get over voltage and destroy the LED. There by we can follow the LEDs as they light up from Green to White and then finally to Red making a sound.


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