Water Level Indicator With Alarm

Introduction: Water Level Indicator With Alarm

Today I am going to talk about a very useful project that I had taken up. It is called the Water Level Indicator. Nowadays everybody has overhead tank at their homes. But everyone who has a water tank above knows the kind of problems that they face. Firstly there is no system to track the water in the tank. Then there come a secondary problem that is when their water pump is started they have no idea when it gets filled up and sometimes there are situation where the pump keeps on pumping water to the tank and the water starts spilling out from the tank. There is wastage of energy as well as wastage of water.

Step 1: Things You Need...

4 - bc548

6 - 220 ohm resistors

3 - colour led

1 - buzzer

1 - 9v battery + battery clip

Step 2: Circuit Diagram

The circuit consisting of 5 sensing probes which is dipped in water to sense the level of water. The probe A is connected as common to other four , which should be at the bottom most part of the water tank, also it act as a reference level. The probes B, C, D and E are set as minimum, minimum+ , middle and maximum level respectively.

Assemble the circuit...... 

Step 3: FINISH.. :)

When water in the tank touches the probe A and B both, a small current flows from A to B through water and to the base of transistor T1 via a 220KΩ resistor. As a result the transistor conducts causing the LED1 to glow. Similarly, when water touches sensor C, LED2 glow and indicates that WATER is at minimum+ and when water touches sensor D , LED 3  glow and indicates that WATER is at. MIDDLE . Finally, when the water touches sensor E ,  BUZZER turns on and indicates the tank is completely filled.

3 People Made This Project!


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    Tiny Home Contest
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    Water Contest
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47 Discussions

This is exactly the circuit I was looking for but battery wouldn't work for me as it's in a machine shop and we have too much going on to keep track of it and I don't feel like making a low voltage circuit, but I do have a 5v 1A wall wart, and all my math says I can do it, albeit my LED's may be dim...thoughts?

Also, very nice instructable, but maybe you could put the specs of some of the things you used (i.e. wattage of resistors, speaker specs etc.)? I know that for this circuit you could easily use a 1/8w resistor but the speaker I just kind of hummed a few bars and faked it and used a 1.5v speaker and put an LED in front of it to step the voltage down a touch.

3 replies

I'm going to use a voltage divider and knock it down some. I lose a little in heat but it's for a Wire EDM water tank that I'm constantly over filling (and that wreaks havoc with the accuracy) so it'll get some cooling. Thanks for the response!

thankyou sir , for your positive feedback .

maybe you can by modify the above circuit accourding to your requirement . :)

This can prove useful in my boat. Thank you much for posting

1 reply

can we use mobile charger which is smps based . is smps power supply is safe ? or in future chances of electric shock ?


1 year ago

Made something like this only difference I put the alarm on empty with a pnp- instead of a npn-transitor

mean agar tank 3rd floor pay ho toa wire almost 40 to 50 feet ban jaye gi? kya yeh circuit itne wire pay support kr sake ga, ore kya hum 12v ka adopter use kr sakte hai circuit mai kuch changing kr k?? reply me soon, i need to make this to save water and electricity

I am a novice and am trying out such simple circuits. 1 question - why does this circuit need a transistor? Can we not just use resistor & LED and avoid transistor?


2 years ago

Hi Dude! Thanks for your instructable! But...I need to be able to tell water level in my catamaran's multible water tanks, and I suspect that, because the water is shoshing around inside, that the circuits would be closed inadvertently? So, no go for my situation??? thanks for any suggestions..Summary: if water level is not constant, level cannot be reliably read out, right?

great work I am also going to make it... but can I use a 12v dc adapter or a mobile charger???

I'm surprised.

I made this on breadboard with 2n2222 and that works but I'm wondering why the leds are blinking?
And a question, I'm using 5V 1A wall adaptor, what register I should use?

I'm surprised.

I made this on breadboard with 2n2222 and that works but I'm wondering why the leds are blinking?
And a question, I'm using 5V 1A wall adaptor, what register I should use?