water tank level sensing

I'm looking for a solution to monitor water levels in a number of large rainwater/springwater tanks.

Obviously one solution would be to use a simple float switch and some form of binary sensor (such as a Shelly), this could at least report an empty tank or other arbitrary level, however what i'm seeking is an indication of water level from which i can calculate litres remaining. There's a mention of the binary/float switch approach in this forum in relation to well monitoring but this isn't what i need.

There are numerous integrated solutions out there using ultrasonic sensing of the water level, however I can see no mention of anyone integrating with Indigo. The ultrasonic sensors have an additional advantage of operating from the top of the tank so nothing needs to be installed underwater.

Wondering if anyone has a success (or failure) story on water level sensing (eg using a sensor attached to an RPi)?

Hi

I have been through a number of ways to do this.

Vege - water level sensor based on wire (I’ll find link). Worked for a year or so and then died.
https://www.vegetronix.com/Products/AquaPlumb/
(This one - website has been updated and looks good - just couldn’t quite get there. Wondered whether because in my use case the wire is always ‘wet’ - but not always submerged…)

Also tried - Ultrasound sensor - never could get working probably

Finally moved to:

Pressure sensor on bottom of tank - connected via RPI.

https://www.ebay.com.au/itm/38399890968 ... media=COPY
Like this - with whatever sensitivity depth etc. needed.

Calibrate and set.
Lasted 4 years+ and simple to replace when died.
I get about 0.25cm tank resolution.

It worked so well - I now have a second one monitoring a slightly smellier tank (septic) which also is working fin.

(I’ll edit this with some links)

Glenn


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thanks for that... i did see those pressure sensors - make sense.! I'd also considered a pressure sensor connectable to tank's outlet but these would be easier.
what are you running on the pi for indigo connectivity?

thanks for that... i did see those pressure sensors - make sense.! I'd also considered a pressure sensor connectable to tank's outlet but these would be easier.
what are you running on the pi for indigo connectivity?

If it was me I'd be running Node Red with the MQTT sender.

I use a RPI with a 4-20mA ADS1115 to read the pressure sensor

Personally I like these converters - although compared to RPI relatively expensive. But easy to daisy chain sensors together.
https://ncd.io/4-20ma-converters/

Benefit of RPI rather than something simpler is had some wifi range issues and needed a USB wifi antenna to connect. But - as Joe suggests - a simpler hardware solution might be ideal…. Would need to read the 4-20ma single though…


Glenn


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pressure sensor & RPi interface (+node/red to MQQT integration) looks like a good end-end solution, thanks for both suggestions - both look mutually compatible

Just to give you another option you could use a Fibaro Universal Binary Sensor. They support up to 4x DS18B20 temperature sensors and they seem to update prety quickly on my use case so I presume they will update reasonably quickly when they are covered with water and when they are not as the ir temperature will be quite different than the water temperature. You could place them at different levels, say 20%, 40%, 60%, 80% to know at what level your tank is. The DS18B20 temperature sensors are relatively cheap here in the UK

that's quite a clever hack! i have a few of those lying around!
I guess (at least for part of the year) there will be a period each day when the air and water temperatures do align? does that cause you problems?


edit: some of the tanks are beyond zwave range. so i need a wifi solution...these sensors do work with shelly devices as well so not out of the question.

Personally I like these converters - although compared to RPI relatively expensive. But easy to daisy chain sensors together.
https://ncd.io/4-20ma-converters/

Have been reading up on ADS1115 interface options - the NCD devices do appear to remove a lot of the hardware DIY with I2C, which is attractive.

So a query: the pressure sensor you linked is specified to require 24V whereas if i read correctly the NCD converters are capable of supplying only 16volts to the sensor. There are [actually identical looking, marginally more expensive] pressure sensors spec'd at 12-32VDC - presumably thats the better option - are you running your sensor directly from the NCD board?

Yeah - the linked sensor was a generic one.

I’ll find the actual one is use given this issue:

This one:

AU $63.93 | 1pcs New version 304 stainless steel level transmitter / 4-20MA Level Controller / 24VDC 2 lines 0.5％ input type level sensor
https://star.aliexpress.com/share/share ... ocialShare


NCD to RPI via i2c, and sensor (2 wire) connected to NCD.

That one seems to say is 24V as well, although works fine (and I now have 2 of them going). Would presume they are all the same and have a voltage range they accept…..

great, thanks for clarifying!
there are loads of near-identical ads for those sensors. I guess i may as well order one with the right range specified...lets see what happens!

Word of caution with these sensors, be careful with the cable length. They will not necessarily work over long cable runs so depending on what you are planning you might need to have the rpi close to the sensor. I couldn't get DS18B20 temperature sensors to work over 4mts of cable, luckily I tested my setup before laying the floor so I was able to move it for a shorter cable run. The aliexpress link that Glenn shared does mention that "If you need other ranges, please contact us for quotation" so I presume they can calibrate the sensor output for longer cable runs.

Hi

The Sensor I linked to the calibration refers to the depth sensor. 4-20mA refers to 0-1 metres, or 0-2 metres, etc.. Nothing to do with cable lengths etc.

They’ll send whatever you request - my common one is 0-2 metres.

If tank is 2metres high e.g. the 0-2 metres sensor gives best sensitivity. Max’s out at 20mA at 2m for example.

My RPI are outside next to sensor - and it probably does need to be close as power is supplied via Rpi to long and will have to much voltage drop.


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Nice to know Glenn, thanks.

interesting.

I have a few DS18B20s on about 6m runs....though of course they sending on the '1-wire' digital protocol not analogue so a range of shielding issues could arise. I think 1wire is theoretically capable of supporting 100m. I do find a sensor occasionally drops off the system requiring a Shelly reboot but I have this even with 1m runs.

4-20ma analogue sensors' claims to fame include supporting long (unto 300m) cable runs (sounds like a lot). I'm gonna try to leverage an existing waterproof enclosure that will require about 10-15m cable run (and have the rpi in acceptable wifi range). Worse case I'll move the pi closer.