Go Down

Topic: Waterlevel sensor with MPX5050 (Read 366 times) previous topic - next topic

RogMoe

Jul 20, 2018, 03:31 pm Last Edit: Jul 20, 2018, 04:57 pm by RogMoe
We installed a 3000 ltr concrete rainwater cistern in our garden to flush the toilets and water the garden. The pump pushes the water through a pressure switch. Right after the pressure switch some water gets filtered and goes to a separate line that runs to the the toilets (and in future to the washingmachine) and the unfiltered part goes to the garden taps. It works like a charm!
I have however no system to tell how much water is in the tank. After searching the Net I found a few solutions. In my opinion using a pressure sensor is the best option. I picked a MPX5050 because it's easily compatible with Arduino. Before continue read this link:
https://circuits4you.com/2016/05/13/water-level-measurement-arduino/

Problem with using a tube filled with water, is that -over time- air and water will mix and therefor cause unreliable readings. My workaround is to use a mini medical infusion bag. I got mine from a local pharmacy and it contained salty water. Empty it, let it dry and attach a watertight tube to it. Next I took an old lunchbox from my kid and poured concrete in it to prevent it from floating. The rubber tube sticks out from one side. Close the box and make sure that there is some air in the bag to compress. Attach the presure sensor on the other end and make sure everything is air tight. Proceed with the electronics as discribed earlier. When finished, lower the box into the tank onto the bottom. Make sure it stays on the bottom. Attached a thin wire to it to raise it out of the water if needed. Mount the sensor ABOVE the waterlevel and run a wire to your controler.

This way no water can come into the tube or sensor and therefor it can't mix with the air. The pressure buildup inside the bag with travel through the tube, thanx to Pasca's Law








ardly

You don't seem to have a question.
You should probably have posted in Exhibition /Gallery
http://forum.arduino.cc/index.php?board=29.0
"Facts do not cease to exist because they are ignored" - Aldous Huxley

RogMoe

I'm sorry for posting in the wrong space. Maybe a mod can fix this? I was just trying to share my knowledge...

Wawa

Air will eventually leak away (sensor barb etc.).
A "bubbler" could be more reliable over time.
Leo..

Nick_Pyner

I have however no system to tell how much water is in the tank. After searching the Net I found a few solutions.
There is a great swag of level devices available on the market for rainwater tanks but, as far as I'm aware, none use a pressure sensor. This is probably because it is not such a good idea.

In the domestic arena at least, I submit this is a rather pointless exercise in the sophisticated aquisition of useless information. The most anybody needs to know, if anything at all, is an alarm to tell when the tank is down to its last couple hundred litres, and there are plenty of drop-in float switches that are good for that. Common practice is to use a rainsaver to provide automatic town supply backup, thereby removing the need to know the level in the tank. 

If you want to get technical, it may be possible to use an Arduino to monitor the performance of the rainsaver. I don't know what you would do with the result, but it might help you identify which stable door to close after the horse has bolted.

TomGeorge

There is a great swag of level devices available on the market for rainwater tanks but, as far as I'm aware, none use a pressure sensor. This is probably because it is not such a good idea.
Sorry Nick....   Google   submersible water pressure sensor.
The water utilities use them to measure the depth of poo in the sewage plants and water in their storage tanks.
I have repaired/calibrated them when the techs at the plant clean the sensor with a screwdriver... oops.. :)


Tom... :)
Everything runs on smoke, let the smoke out, it stops running....

Go Up