So even if you achieved 0.25mm resolution by whatever method, what would it mean?
Low budget would be ideal (like under 200).
What is the application?
How about making a regular rain gauge.
The civil engineer in me is guessing this might be some kind of hydrological assessment of drainage rates vs the amount of rain.
Not really feasible with ultrasonic, especially at that rather low frequency - the wavelength is far too long for 0.25 mm resolution. 340 kHz = 1 mm
Surely in heavy rainfall there will be severe disturbance of the water surface due to the raindrops... and if the water is flowing, significant ripples.So even if you achieved 0.25mm resolution by whatever method, what would it mean?Allan
Yeah even if it was mirror smooth, I can't think why 1/4mm would be significant.Adafruit have these which do purport to have 1/4mm resolution.You're the only one who knows the units of the 200 budget. Adafruit's USD40 may or may not be within that, who knows.
But the idea of measuring the water depth on the ground in a rainstorm to a precision of 0.25mm suggests that the OP is not an engineer....R
I'm working on a project given by a professor in civil engineering.
If rainfall is sufficiently intense, water does not drain away quickly and cause appreciable depths to build up and cause accidents.
That's as may be: it makes no sense to me (and I'm a civil engineer, although not a Professor....) to even think of measuring water flowing in the road to within even 10mm or so, I'd say. It's not a matter of the precision of the measuring device, but the fact that the water's height will be varying by that much except when it's a settled puddle. Just the natural movement of the water across a road with its surging and turbulence would make me think I'd be lucky to measure to 5mm at best. Regardless of my equipment.Different in the hydraulics lab of course, but in a real road? Doubtful.
so if you had 50 units you could study how 2D kinematic waves work at a small scale, if possible.