non-contact water detection

[Ca++]

Has anyone messed about with non-contact water detection?

These cost essentially nothing. Work off 5-24v, and offer an output signal for other devices (should you wish).
This one pictured has an adjustment screw, and can see water up to 20mm away.
Here is one add of many https://www.aliexpress.com/item/1005002210054923.html

It's the level of adjustment I'm interested in. My roots dangle out into a saucer. I would like to put one under the saucer, to know when the waters gone. However, I have roots sat in it. It won't be just air. Then I got to thinking, could this be repurposed to tell us when a pot is getting dry. A moisture sensor, that need not go in the pot. I imagine it has uses in both projects, but as I need 8, I thought I would ask if anyone has seen them used.

 

[Creeperpark]

Has anyone messed about with non-contact water detection?

These cost essentially nothing. Work off 5-24v, and offer an output signal for other devices (should you wish).
This one pictured has an adjustment screw, and can see water up to 20mm away.
Here is one add of many https://www.aliexpress.com/item/1005002210054923.html

It's the level of adjustment I'm interested in. My roots dangle out into a saucer. I would like to put one under the saucer, to know when the waters gone. However, I have roots sat in it. It won't be just air. Then I got to thinking, could this be repurposed to tell us when a pot is getting dry. A moisture sensor, that need not go in the pot. I imagine it has uses in both projects, but as I need 8, I thought I would ask if anyone has seen them used.

Can you post a photo so we can see what you are talking about?

 

[Ca++]

Can you see this one?

It senses the presence, and puts on the light. It also sends out a signal down it's wires. This can be RS485 for the more PC literate, or simply a high/low logic state. Which could control an LED indicator, or relay.

My own use, is in this system.

It's drip to waste. Bucket in bucket. The outer one forms a shallow reservoir, that the inner one doesn't quite reach. The roots drop in though. The little wooden stand offers the opportunity to place a sensor underneath. This would give a visual clue as to when they were drying. Ideally A root shouldn't be dry for more than half an hour, but they don't always drink at the same rate. If it worked, I would wire them all together and form an alarm. Perhaps even automation. That's another project though.

They do tend to drink up at a similar rate, as fluid can move between them. Floors are never quite as level as you would like though. There are 5 arrows in this pot, having taken one from a neighbour. I need to get my spirit level out. A set of lights would of already shown me this though.

The little black tub is the lowest, as it's the drain pump in there. A high level sensor in there, could cut out the drip pump in a fail situation. I could use these cheap little things. I will order just one I think. See how it performs.

They set up an electromagnetic field, which they also monitor for deviation caused by things entering it. The fluid could probably creep past it, if it took a day or two over it. A little processor makes the decision. The sensitivity of which, we can set with a screwdriver on many.

 

[Ca++]

I ordered one for my water presence monitoring.

I think for soil moisture, it's just too easy with the newer sensors.

50cents, and $1.50 to ship a fair few.
Runs off an old 5v charger. Outputs between zero and three volts, to indicated how wet.

https://www.aliexpress.com/item/1005004107976169.html

0.5" green numbers, 0.00v resolution. Another $3.

For actual control, you could get another dollar fifty out

https://www.aliexpress.com/item/1005005506836637.html

That could flick a $2 pump on, keeping a steady moisture level, like a carrot should. If you place the sensor in one side of the pot, and water the other, you can get a bit of pump run time. Or... it you got this far, get a monostable 555 board. So if the pump runs, you can pick for how long.

Not really my project, but the 555 part is. When I see a dry res, I will drip for an amount of time. I just brushed over the moisture sensing, to wrap up that idea (unless anyone wants help with it)

 

[mean mr.mustard]

Nothing that fancy...

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