This document describes a water level indicator circuit project created by a group of students. The circuit uses three probes placed at different water levels in a tank connected to an IC, resistors, transistor, buzzer and LED. It indicates the water level and alerts when the tank is empty or full by activating the buzzer or LED. The circuit works by completing a conductive path between the probes when water reaches each level, controlling the transistor and alerting the user.

1. WATER
LEVEL
INDICATOR
GROUP MEMBERS:
SHUBHI VERMA
SHRIYA SINGH
SAKSHI TYAGI
SMARTY SHARMA

2. Water Level Indicator With
Alarm
 The Water Level Indicator employs a simple mechanism to detect and indicate the water
level in an overhead tank or any other water container. The sensing is done by using a set
of three probes which are placed at three different levels on the tank walls (with probe 3
to probe 1 placed in increasing order of height, common probe (i.e. a supply carrying
probe) is placed at the base of the tank). The level 3 represents the “tank full” condition
while level 1 represents the “tank empty” condition.

3. COMPONENTS :
FOLLOWING ARE THE REQUIRED COMPONENTS FOR MAKING WATER LEVEL
INDICATOR CIRCUIT:
1. IC NE555 (TIMER IC)
2. RESISTORS: R1 =10KΩ; R2 =47KΩ; R3=470KΩ
3. BUZZER
4. 9V DC BATTERY
5. TRANSISTOR: BC548
6. PCB BOARD
7. LED
8. CONNECTING WIRES

4. Circuit:

5. DETAILS OF COMPONENTS:
 IC NE555: The 555 can be used to provide time delays, as an oscillator, and as
a flip-flop element .It is a very commonly used IC for generating accurate timing
pulses.
 Resistors: Resistor is a passive component used to control current in a circuit .Its
resistance is given by the ratio of voltage applied across its terminals to the
current passing through it.
 Buzzer: The buzzer produces sound. It is also used in alarm circuits.
 Transistor: In this ckt we use bc548 transistor, which is a common emitter NPN
transistor. This is basically used for amplification and switching purpose.
 9V DC battery: It is a collection of one or more electrochemical cells in which
stored chemical energy is converted into electrical energy . The principles of
operation haven’t changed much since the time of Volta . Each cell consists of
two half cells connected in series through an electrolytic solution.

6. IC 555
 The 555 can be used to provide time delays, as an oscillation, and as
a flip-flop element.
 It is a very commonly used IC for generating accurate timing pulses.
 It is an 8pin timer IC and has mainly two modes of operation:
monostable and astable.
 In monostable mode time delay of the pulses can be precisely
controlled by an external resistor and a capacitor whereas in astable
mode the frequency & duty cycle are controlled by two external
resistors and a capacitor.

7. Pin diagram of IC 555

8. Circuit diagram:

9. WORKING:
 The operation of this project is very simple and can be understood
easily. In our project “water level indicator” there are 3 main
conditions:
 There is no water available in the source tank.
 Intermediate level i.e. either of 3rd to 7th level.
 There is ample amount of water available in the source tank.
 So let us discuss on the more about these 3 conditions

10. Condition 1:Water is not available
 When the tank is empty there is no conductive path between any of
the 3 indicating probes and the common probe (which is
connected to 9v+ supply) so the transistor base emitter region will
not have sufficient biasing voltage hence it remains in cut off region
and the output across its collector will be Vc approximately 9v and
thus indicates, the tank is empty.

11. 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 outputs will be Vce (i.e. 1.2v-
1.8v) approximately which is given to microcontroller. Here the
microcontroller is programmed as a priority encoder which detects
the highest priority input and displays corresponding water level in
the seven segment display. In this project while the water level
reaches the 7th level i.e. last but one level along with display in
seven segment a discontinuous buzzer is activated which warns user
that tank is going to be full soon.

12. Condition 3:Water full
 When the tank becomes full, the top level probe gets the
conductive path through water and the corresponding transistor
gets into conduction whose output given to microcontroller with this
input microcontroller not only displays the level in seven segment
display but also activates the continuous buzzer by which user can
understand that tank is full and can switch off the motor and save
water.

13. Applications:
 Automatic Water level Controller can be used in Hotels, Factories,
Homes Apartments, Commercial Complexes, Drainage, etc., It can
be fixed for single phase motor, Single Phase Submersibles, Three
Phase motors. (For 3Æ and Single Phase Submersible Starter is
necessary) and open well, Bore well and Sump. We can control two
motor and two sumps and two overhead tanks by single unit.
 Automatic water level controller will automatically START the pump
set as soon as the water level falls below the predetermined level
(usually 1/2 tank) and shall SWITCH OFF the pump set as soon as tank
is full.
 Fuel level indicator in vehicles.
 Liquid level indicator in the huge containers in the companies.

14. Need of water level indicator:
 Overflow problems
 To prevent wastage of energy
 To prevent wastage of water
 Observation