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Topic: Water Level Monitor Sensor - Hydrostatic Pressure (Read 155 times) previous topic - next topic

jordan_kaiser

Hi Everyone! Thanks for stopping by! 

I'm relatively new to the electrical engineering and instruments and controls world, though I have 5 years experience as a mechanical engineer, so a little extra explanation is appreciated!

The question: I am trying to build a proof-of-concept circuit using an Arduino UNO that measures water level in an open container. What sensor would be best for this circuit? Ideally, the sensor should be able to be in direct contact with the working fluid (tap water) on one side - my intent is to measure the hydrostatic pressure of the water via a port and tube at the bottom of the container. The tube will be filled with water and attached directly to the sensor port. The operating pressure range is 0-1 psig. I am familiar with analog and I2C protocol but I can learn a different communication protocol if necessary. 

I have spent hours filtering pressure sensors on Digi-Key and have tried a few options, most recently the NXP MPVZ4006GW7U. This sensor is nearly perfect, except the datasheet says "for dry gas" despite the datasheet also saying possible applications include water level detection, so I'm hesitant to hook up a hose full of water to it. I figure I'd reach out to the community to see if anyone else has experience with this topic. 

Side note: if someone knows of a breakout board or similar assembly that already does this, please let me know. I don't need to reinvent the wheel. 

If I can provide any additional information please let me know! 

Thanks for your time! I appreciate any and all input!

mikb55

#1
Jan 24, 2021, 11:46 am Last Edit: Jan 24, 2021, 11:46 am by mikb55
Search for "bubbler level sensor".
For a hobby project you would use an aquarium air pump and a one way valve. Switch on the pump, monitor the pressure until it stops rising, switch off the pump, wait a couple of seconds then take a reading.

Ron_Blain

If you want simple, quick and economical I would be looking at, as suggested, a bubbler system

Ron 

hammy

 Most low pressure sensors have the sensor element open to the measuring fluid rather than a stainless steel wetted diaphragm - which is what you need .
( the diaphragm adds some stiction to  the reading unless a large area ( ie expensive) transducer is used) .

The bubbler uses dry air so overcomes that issue and worth a punt , I would come up with a system that didn't leave the sensor ( when not bubbling ) exposed to damp air , which will still shorten its life . The NRV sounds a good idea as mentioned  or a solenoid valve

As an aside some early car fuel gauges used this principal where you had a little hand pump and pumped away every so often.

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