I am designing water level controller for water tank and want to show the water level in LED bar Graph

I know how to transmit data to MCU and show level to LED bar graph but my problem is to find the sensor for continuous level measurement i searched in google and find out that there are floating switch type device which track discrete level. But that will not measure the continuous level of water and i also came across ultrasonic sensors that measure the level continuously

Is ultrasound sensors are reliable and efficient method?

My other question is what type of other sensor are available that can measure water level continuously and efficiently?


A bit of googling helped:

With some liquid media, however, these ultrasonic waves are absorbed rather than reflected. If you’re thinking about using an ultrasonic level sensor, be sure that your liquid medium reflects ultrasonic sound rather than absorbing it.


Agitated liquids, turbulent liquids, foaming, sloshing, and other activity can hamper the performance of ultrasonic sensors. In applications where liquid agitation is common, ultrasonic sensors may therefore be a poor choice.

Alternatives mentioned: submersible pressure sensors (hydrostatic pressure level sensor), optical liquid level sensors


I find that ultrasonic sensors work great for this type of thing.

I'm currently building a water purification plant automation system for the private community I live in.

We've got a 55 gallon tank that contains a water/chlorine mixture that delivers this into the main water feed lines (from two submerged pumps in our lake) before they enter the pressure tanks.

I use two ultrasonic distance sensors for the measurement (one as primary, the second as a confirmation unit). When the level gets to a low point (measured by exponential average), I engage (ie. open) a solenoid for water (timed with a flow sensor), and at the same time, pump in chlorine to my prescribed amounts. While filling the tank, I monitor the raw data instead of average, then when I hit my high mark, I shut the pump/solenoid off.

I also have a float valve, so that if for some reason something goes wrong and the tank goes too full, it'll do an emergency all-stop on the system.

For testing, I'm using simple HC-SR04 sensors, but I've also got a couple of waterproof ones that I'll be using in the production system.

As another poster mentioned, if the liquid is always in a rather turbulent motion, or doesn't reflect back the sound waves, ultrasonic is not the way to go.


I think the best way is using FDC1004 (from TI). This sensor is very useful for capacitive un-touch water level measurement.

I wish I worked for TI, but I don't.

I use TI FDC1004 for level sensing. This IC has 4 capacitive reading output, and one of them is used for level sensing. The second one is using air capacitance and the third is used for water capacitance. For these reasons, the system can not make an error during level calculation. Also, this IC has a shield for EM filtering from outside.

For more information, please look at Liquid Level Sensing with the Immersive Straw Approach, which is why I advise using this IC.

  • 2
    \$\begingroup\$ Recommendations for specific products rarely have lasting value, particularly when you don't explain why you recommend a particular product. Some might suspect you have an affiliation with TI. \$\endgroup\$ – Elliot Alderson Feb 24 '19 at 13:43

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