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RPi - Monitor Water Butt water level - Reed switch or Ultrasonic?


0phoi5

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Hi all,

I'm working on a project to track the water levels in a water butt in my garden.

I plan on installing a DIY irrigation system, which will consist of a pump sitting in the water butt. As I don't want the pump to switch on when the water level is too low, to save it running dry, I wish to monitor the level of the water inside the water butt.

I've researched around for the best method, but it's very difficult to judge which will work best and is most cost effective! So far, I've considered doing one of the following with a Raspberry Pi;

  • A reed switch/sensor, with a magnet floating on the top of the water, inside a tube, in the water butt. When the magnet reaches a low point within the tube, the reed switch picks it up and trips.
  • An ultrasonic sensor on the underside of the lid on the water butt
  • 2 long metal rods, with current, sitting down to near the bottom of the water butt. When the current running between the rods drops, when the water goes lower than the tips of them, then a script will kick in.

 

Any thoughts on these? Has anyone done anything similar or have any ideas?

Thank you

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nice project, did you already consider float switches?  https://www.amazon.com/Copapa-Horizontal-Liquid-Switch-Sensor/dp/B00AKW29U2  can proib find cheaper.

Just tells you if water is above or below the switch position but you could use a few at different levels of the water container to give you an idea of water level. e.g. Full, 3/4. 1/2, 1/4, pump min.

The bottom one (pump min) I would perhaps use some redundancy 2x in parallel (if using NO, serial if NC) at the same lvl so you only need one to switch to make sure you don't pump dry.

Edited by Just_a_User
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2 hours ago, Just_a_User said:

nice project, did you already consider float switches?  https://www.amazon.com/Copapa-Horizontal-Liquid-Switch-Sensor/dp/B00AKW29U2  can proib find cheaper.

Just tells you if water is above or below the switch position but you could use a few at different levels of the water container to give you an idea of water level. e.g. Full, 3/4. 1/2, 1/4, pump min.

The bottom one (pump min) I would perhaps use some redundancy 2x in parallel (if using NO, serial if NC) at the same lvl so you only need one to switch to make sure you don't pump dry.

I would agree this is a good solution especially with the added redundancy.  Have done similar in a system that monitored the level of a grain bin to turn an auger on/off for transfer of grain.  No matter the switch type, I would use some sort of redundancy to prevent dry running of a pump,motor, etc.

 

57 minutes ago, barry99705 said:

Fun fact, fuel level sensors in jet aircraft are capacitive sensors.  It's a tube with a metal rod down the middle, runs a current through the jp-8 to determine the level.

That is really cool! Nothing like a little electric in your fuel.

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