This circuit is designed to indicate the level of water in any type of vessel (tank) to prevent the over flow of water and many other uses. As the water level increases from the base of the tank, the number of glowing LEDs with different colors increases subsequently. Amount of water present in a water tank can be easily measured.

1. A presentation by:
Sajeed Mahaboob
2011ME1111
Guided by:
Dr. Ranjana Sodhi
16-Nov-11 1

2. Introduction:
This circuit is designed to indicate the level of water in
any type of vessel (tank) to prevent the over flow of
water and many other uses.
As the water level increases from the base of the tank, the number
of glowing LEDs with different colors increases subsequently.
Amount of water present in a water tank can be easily measured.
16-Nov-11 2

3. Components List:
Circuit elements used are as follow:
IC1 CD40106.
470 K Ω Resistor.
270 K Ω Resistor.
Sound Buzzer.
Capacitor 1000 µF 16V.
Battery (9V).
LEDs 2Red,2Green,1Yellow,2Blue.
14 Pin IC Socket.16-Nov-11 3

4. About Circuit Elements:
IC1 CD40106:
IC CD40106 provides six inverting buffers with Schmitt trigger action.
The buffers are capable of transforming slowly changing input signals
into sharply defined jitter-free output signals.
They are usually used as wave and pulse shapers.
270 K Ω Resistors:
In order to set the voltage bellow 12 V, we put 270 K Ω resistor,
setting base to some low voltage.
LEDs:
Light Emitting Diodes, Placed in circuit, to show
level of water in vessel. These diodes are operated at 1.5 V
16-Nov-11 4

5. CAPACITOR (1000µF 16v):
This capacitor is a passive two-terminal electrical
component used to store energy in an
electric field, and also prevents the sudden
fluctuation of current in the circuit.
470 K Ω Resistors:
470 K Ω Resistors are installed in the circuit because
LED is Operated at 1.5 V, and we are having 4.7 V there,
so in order to decrease the voltage across LED we placed
470 K Ω resistors
16-Nov-11 5

6. Working of Circuit:
• When any wire is dipped in water that wire will be
connected to wire N (common probe) through water,
establishing a negative voltage across the base of diode.
Current begins to flow from circuit. In this way, LED
glows.
• After successive connections of wires with N,
respective LEDs will glow, and when wire F will be
connected to N , then there will be sound alarming you
that water has attained maximum level and after this
water will flow over.16-Nov-11 6

7. 16-Nov-11 7

8. Applications of Circuit:
This Circuit has a number of practical uses in daily life.
Now the circuit is ready to indicate the level of water in tank.
Can be used to measure underground storage of water.
This water level Indicator works to maintain a constant water
level.
Alarm starts ringing as soon as tank becomes full.
It helps to check overflow and wastage of water
by warning the person when the vessel is about to brim.
It can also be used to calculate incoming and out going water
in large reservoirs also.
It is used to predict the arrival of floods.16-Nov-11 8