Simple Water level indicator using Logic IC

This is a simple water level indicator circuit which can be used to indicate water at 3 stages EMPTY, LOW and FULL by three respsctive LEDs.

The heart of this circuit is a 4011 NAND IC. You have to supply 3 volts to this circuit possible from two AA battery and connect the -ve terminal to lowest level of tank by a wire, you can tie this to the metal pipe outlet of tank.

The L terminal will go from up to down upto the lowest allowed level of tank and the F terminal wire should hang with tank’s cap upto the full water level’s height.

A simulated prototype bellow, check the circuit diagram and working principle for more details about this project.

Working principle:

  1. When water is below low level, both terminal(TP1, TP2) goes high by 10K pullup resistors and thus LED-EMPTY glows only.
  2. When water level is above low level, but below high level then TP1 is low, and TP2 is high. This makes only LED-MID ghlow.
  3. When water level is above full,then TP1 and TP2 both comes to low, and every LED glows including LED-FULL indicating it’s time to turn off motor.

 

Note: Full water level could be shown in one LED only, but to make the circuit much simpler I used one logic IC and hence the result being all LEDs on at full water level. You can use 7400 IC too as replacement of 4011, but 7400 IC will require 5V supply and you need to add a series 100Ohm resistor to the LEDs to run them at 5V.

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6 Responses

  1. emzie says:

    I ALREADY FINISHED THE CIRCUIT AND CHECK THE CONNECTIONS MANY TIMES BUT STILL IT DOESN’T WORK…WHAT IS THE POSSIBLE CAUSE OF THIS PROBLEM?
    I NEED A REPLY PLZ..TNX..

    • Arup says:

      This circuit was logically constructed and there was not any real test. I’ll test it and modify if necessary and let you know.
      Thanks for the comment.

  2. Zubair says:

    very nice
    well job.Dear….,!

  3. ashish says:

    if well is empty then how can we fill water from ?? can any indicator we add in this circuit ?and also low n high voltage control yo protect motor

  4. ashish says:

    if well is empty then how can we fill water from ?? can any indicator we add in this circuit ?

  5. Suresh E says:

    Tell me a detailed construction of this circuit pls….
    i poor in digital…..

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