water level monitor electronic circuit

Water Level Sensor Circuit

This simple water level sensor circuit monitors the presence of water in a certain location or container. The circuit sends an acoustic alarm when it senses a drop of water leak. It is very simple to build and it is made of a single IC and some passive components. Check out the water level indicator circuit too!

The IC LM1801 is a low power comparator that can deliver high output current if needed. When water hits the sensor, the reference voltage is overshot and the IC drives the ceramic transducer to beep. It is also possible to connect several sensors to the water level monitor circuit. The sensor can be easibly made out of a small piece of PCB that is etched with the proper pattern. The decoupling capacitor C3 is a 100uF/16V electrolytic capacitor.

Water Level Sensor Circuit Diagram

water level monitor electronic circuit

Water Level Sensor PCB and Parts


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  • Ray

    I used a damaged gold plated connector and cut it up to make contacts. Gold does not rust.

  • dave

    you can use a pcb that is etched with to traces. tin them. the number of decades it will take for the lead to be covered to the point it is not a conductor would mean that your grand children’s grand children may have to remind their grand children to clean it.

    what puzzles me is why anyone would even think about using parts that have a high probability of failure.

  • SMeter

    Pulak, I see what you’re saying. When the corrosion starts, it will be hard to stop and then a whole section of the sensor will need to be replaced – not fun. An idea would be to thinly insulate it like this Not sure if it would work, but its an idea

  • Pulak

    Water is a good conductor of electricity so when you put two open wires inside the water the current flows through water thus indicate the level of water.
    But when metal gets rusted then the flow of current stops and will not show the level of water at all. This is the real problem. So we have to find out the other way out. Either using light sensor or ultrasound sensor will help and will not give any problem but when it stops working then you should clean and that is for 5 years or so. Right! So start making such kind of circuit that will help you and others well in problem free working.

  • Mark

    Saw this schematic and thought I would like to build this. Does anyone have an idea where to find LM1801? Cannot find it on National Semiconductor used to build this but Texas Instruments bought them.

  • masih

    i dontknow but seems work:)

  • ali

    does it work?

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