I want to create a project where I check, how long it takes something to sink into water (when it is gone from the surface)
My first thought was to measure the distance from above, and check when the distance is no longer changing, as the object must then be gone from the surface.
This could be done using ultrasound, but it is not precise enough as I am measuring in something the size of a glass, and the difference is in mm.
My next thought was using something like a laser, but this would only measure in one specific spot, right? and it needs to check the whole surface.
Then I thought about check the material (is it water or something else) using either ultra sound or light reflection, but i don't know how the glass is going to interfere, or how it works if only some of the water surface is covered and it is covered uneven?
It seems so simpel, and yet I can't figure out a solution.
Any ideas? there can be no physical contact with the surface.
If you can't have anything in contact with the sinking object maybe this needs a camera and image processing - far beyond the capacity of an Arduino.
Would it be possible to put an Arduino inside the sinking object and send data by wireless or flashing lights?
What about a flashing light on the top of the object that could be detected by an Arduino on dry land until the object (and the light) disappears underwater?
Run a laser across the surface of the water. That may pick up waves, so you could not measure down to zero unless the sinking motion is slow enough to not make big waves.
That's really clever. Using the displacement will tell you when it is submerged because it can't displace more. Add a few trapped bubbles of air and the displacement decreases as the bubbles come to the surface.
What about an overflow? When the water stops flowing over the overflow, the object is fully submerged.
DrDiettrich:
When a floating ship sinks, the water level decreases. What are those objects, and why do they sink?
+1. People have been "floating" all kinds of good suggestions. But a practical method depends on the nature and size of the objects, and the size and method of containment of the body of water.
Robin2:
It's very frustrating when there is no response from the OP.
Agreed, and happens all the time. Perhaps we should have a code of conduct here that the OP must respond to an answer or two before further answers will appear, or within 24 hours anyway?
Ralph_S_Bacon:
Perhaps we should have a code of conduct here that the OP must respond
Totally disagree. Firstly, the discussion in itself is interesting to those participating (well, me anyway), and second the suggestions however wacky, may actually help someone else on another day.