Automatic Water-Tank Motor Controller


Introduction: Automatic Water-Tank Motor Controller

You can see the working of this controller explained in the lovely diagram...

Its a simple controller, which would help to turn the water pump on, when your water tank is empty, and will turn it off when the tank gets full, and will keep it turned off until the tank is empty...

Step 1: Working

The lower sensors acts as the 'J' input and the upper sensor acts as the 'K' input in the J-K flipflop...

the working of both the sensors is opposite, i.e. the upper sensor gives output 1 when the water is detected, and the lower sensor gives output 0 when the water is detected...

With this kinda sensing, we can predict the JK flipflop's output as-

when there is water on both sensors, input = 0 1, output = 0 = motor off

when water is coming down after filling up, input = 0 0, output = 0 = motor off

when water comes below the lower sensor, input = 1 0, output = 1 = motor on

when water starts rising from the lower sensor, input = 0 0, output = 1 = motor on

when there is water on both sensors, input = 0 1, output = 0 = motor off

Step 2: The Circuit

The circuit works on 12v dc power supply, which you can give from a 12v DC adapter...

The circuit is built around 3 main ICs-

LM358 - dual comparator - sensing IC

NE555 - timer ic - clock pulse generator

7473 - JK flipflop - the controller/brain

You can see the components and the connections as per given in the circuit...

The components you will need to build this circuit are -

-12v dc jack female

-1x(100uf or 200uf or 500uf or 1000uf) + 1x10uf capacitor

-7805 volt regulator + heat sink

-2x 500k potentiometer

-2x 47k ohm resistor + 2x 470 ohm resistor +1x 330 ohm + 1x 270 ohm + 1x 100ohm + 2x 10k ohm resistor

-LM358 IC + base

-LM555 IC+base

-7473 IC + base

-1x diode

-12v relay = heavy duty according to motor

-2x red led + 1x green led + 1x yellow led

-1x BC547 transistor

-12cmx12cm prefboard

-12v DC adopter

correction - the pin 2 and 6 are connected in the 555 IC in the circuit.
also do connect the Vcc and Ground of all the ICs, you will easily get the pin configuration of the ICs on google...



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    Please be positive and constructive.




    I also want to add a float sensor for underground tank, because if water is not available in underground tank then our motor will be damaged.
    Please tell a solution for it.

    2 replies

    here is the solution, you can add an AND gate and an extra water level sensor module to implement that functionality....


    Thanks for responding.

    Yes, bipods, hexapods, etc

    its grate job very usefull for biginers

    I am planning to try this circuit and wanted to know what kind of sensor need to be used with this circuit?


    I want to try this..but may I know what LED do when running sir..? do they flip-flop when relay start pump "On" or else..coz i'm beginner here..thanx for information:-)

    nice circuit.

    i need little help. actually we have utilitiy water supply problem in my area. there is no timing of water supply. so i want a circuit to start my pump after every 30 minutes if water comes the motor continue to run if water not come motor stop after 1 or 2 minute. any body plz help me


    It's good to see someone designing logic circuits rather than just using a micro controller. I've been using float sensors like this
    They won't get dirty and will also work with fluids other than water.

    hi i made this ckt and its not working...7473 ic's 13 th pin is connectd to something or is it open?

    2 replies

    you need to give +ve and -ve voltage of every IC

    and pin 2 and 6 of IC 555 are connected...

    yeah the pin is open, it is not connected to anything..

    this circuit is fine, recheck your circuit
    if you are still unable to debug it, then upload the pics of your circuit... i will see them...

    thanks for sharing. I think the circuit diagram shows using the first half flip flop while you used the second half, isn't it?

    1 reply

    yes I used just one flip flop

    Hello sir ...u have any video of this project ? Means designing video.

    1 reply

    sorry I didn't make any video of it...

    I paid about 300rs = 4.5USD for all the components.