Water Level Indicator Using IC

The water level indicator is a system that gets information about the water level in tanks which is used in homes and public places. We can control the overflow of water tanks by using the tank level indicator. As everybody know When the water is stored in the tank, nobody can identify the actual level of water in the water tank. That is way mostly water tank overflow and its great loss of water as well as electricity.

Water level indicator

In this simple water level indicator project, we have used a Switching IC ULN 2003  to indicate the water in the tank. Nowadays many projects on water indicators are available such as slope indicator water level meter, Digital water level indicator, water indicator using transistors, water level indicator alarm, etc.

Water Level Indicator Using IC ULN 2003


In this circuit, we are using switching IC ULN 2003 commonly used switching IC. Components used in these Projects areas:

  • ULN2003 is a high current and high voltage Darling-ton array IC. It consists of seven open collector darling-ton pairs with common emitters. Darling-ton pair is an arrangement of two bipolar transistors. It is a relay driver IC other types of similar ICa are high side toggle switch, low side toggle switch, Darlington transistor, bipolar NPN transistor, N-channel MOSFET, ULN2003 driver IC, etc.
  • LED s this ic has 7 output pins that are why we are going to use 7 LEDs as water level indicator in the tank. This LED s will glow according to the Level of water in the tank.
  • Battery: A DC supply of 9V is given through a  battery to power up the circuit or you can use 9 to 12v DC supply as power.
  • Resistor 220-ohm resistors are used in this circuit to protect the LEDs because we are using 9 volts to 12 volts power supply.

Circuit Diagram of final projects

Water Tank Level Indicator

In this following animated circuit diagram, we have cleared all components with their connection you can use long wires according to the distance of your tank to electric board.

Water Level Indicator Using Alarm

We can also use alarm with this circuit. It will alert you that now the tank is full and you should turn off the water pump.


Tank Level Indicator Auto Powered off

We can also use a Cut off Relay with this circuit, When the Tank will be full relay will cut off the power automatically.

Water Tank level indicator

In this circuit given about we have cleared all connections with auto cut off water pump When tank will be full water Pump will auto turn off because a relay is connected with the 7th output of ic.

ULN2003 Pin Description

Pin No
Functions of all Pins 
Input for 1st channel (envirementalb.com))
Input 1
Input for 2nd channel
Input 2
Input for 3rd channel
Input 3
Input for 4th channel
Input 4
Input for 5th channel
Input 5
Input for 6th channel
Input 6
Input for 7th channel
Input 7
Ground (0V)
Common freewheeling diodes
Output for 7th channel
Output 7
Output for 6th channel
Output 6
Output for 5th channel
Output 5
Output for 4th channel
Output 4
Output for 3rd channel
Output 3
Output for 2nd channel
Output 2
Output for 1st channel
Output 1

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