5 ms·
I'm building a system for measuring levels in water tanks using submersible pressure sensors (triggered by living in a dry area and being totally dependant on o
by abraae 5y ago
I'm building a system for measuring levels in water tanks using submersible pressure sensors (triggered by living in a dry area and being totally dependant on our tanks).
Quality sensors cost a lot - too much for domestic purposes. Much cheaper ones can be bought from China, so I've been looking for some way to test them, without actually altering the level in a gigantic water tank.
It occurred to me I should be able to just use a thin vertical pipe. But as you say, this seems counter intuitive, especially if the pipe is barely wider than the sensor itself. Just doesn't... Feel right.
- lazide 5y agoIt’s called head - and it’s a key calculation in if a dam is worthwhile. The pipe feeding the turbine can be quite small for a lot of power if the head is large. You could also use a small pressure vessel/sealed tank, and pump in water with a hand pump. You could simulate nearly any sized tank that way too.
- RantyDave 5y agoIf you stick the sensor at one end of a hose pipe (with water in it) then you can just change the height of the other end to change the pressure.
- abraae 5y agoNice idea, thank you.
- RantyDave 5y agoHey, also, why not just find the height of the water level by attaching something ultrasonic to the inspection hatch (or whatever). https://www.adafruit.com/product/4664 https://www.adafruit.com/product/4664
- vosper 5y agoNot only is this a really cool idea, that sensor is awesome! I love that you can get something like that for $30.
- abraae 5y agoNot accurate enough. I want to be able to quantify e.g how much water was used to water the garden. In a 25K litre tank, that's a very small change in level.
- groby_b 5y agoYou'll have the same issue with pressure sensors, though? Maybe a flow meter is a better choice for that. (Bonus, you can use that to cross-calibrate with the pressure/level sensor)
- snovv_crash 5y agoYep, if you use flow plus pressure, you can run an EKF to get much more accurate results.
- snypher 5y agoYou can get ultrasonics with millimeter precision but they're $300.
- zsmi 5y agoI can totally relate. I've been using ohm/square for decades. I know the math. I've measured it. It works. I know it's true. But my mind refuses to accept that ohms/square can possibly be a unit. Every single time my mind is like, "ohms per square what?" http://www.esdjournal.com/techpapr/ohmmtr/ohm.htm http://www.esdjournal.com/techpapr/ohmmtr/ohm.htm
- tbrownaw 5y agoMy understanding of that is that it's using "square" as in aspect ratio like how screens are 16:9 or whatever, while "square" in units is more commonly used as in `exp(n, 2)`. And that terminology mismatch is why it often doesn't seem to make sense.