our water is off a shared well & feeds to a plastic water tank. I want to do a low-water alarm. Simple, right?
Except since it's shared, it has to be a unanimous decision to change something.
The restrictions so far:
I cannot put anything "inside the tank"
I cannot let anything touch the tank
I cannot touch or alter the water or water flow
I cannot modify the tank or lid
So my thought is to use some sort of sonar placed outside the tank right against the plastic -- figuring if water falls below it; it would get a different reading.
That's my theory anyway -- but the cheap modules I have just detect the tank wall, I am thinking I need more power behind it....
I don't think sonar is going to work through plastic. Not the thick plastic that water tanks are made of. That said, you can use non-intrusive sonar... Link Here
This is a bit of a Schroedinger's Cat situation, is it not? Until you look you do not know. Mmm.
Does touching the tank include placing something under the tank (technically speaking it does but...)? Then you could measure the weight unless we're talking tons of water weight.
I guess you can try all and every theory using a 2 litre water jug and apply the same rules when more suggestions come in.
Sorry - "touch the tank" should have been qualified with "inside the tank" (so no downward facing sonar mounted to the lid -- that was my 1st idea, but one person struck it down "what will that do the water?")
Weighing it would be impossible on my budget --- we're talking 1500 gallons of water.
Yes, anytime a group of people share something, everyone knows better. It seems everyone wants perfection, but no one will take responsibility for it. ("Why should I be responsible for you?") It's a nightmare sometimes. We live on the 1st 100 yards of a dirt road. Two houses farther down drive 30-50 mph in their trucks, then yell at us for the potholes but ignore our complaints of dust.
Anyway -- I actually worked on a project using ultrasonic flow control... the key is "flow" it did not detect 'how much' water exists, just that it was flowing. it was really interesting to work with. I was turned on to it with our boat that used ultrasonic detector for wind direction...
I use these capacitive sensors to detect the water level directly from the outside of the tank. They work well even through the thick plastic of large (12000 liter) water storage tanks and are the perfect solution. They are also called proximity switches.
Simply run the sensor up and down, with the probe tip in contact with the plastic, and the current will change when near water (or your hand, or metal, etc.).
For a low water sensor, install the sensor at a fixed location with the tip touching the outer plastic surface.
Brilliant indeed! ad cheap! Looking at them, I never would have thought they could go thru plastic. (they look like they mount thru the material) -- that's awesome & I just ordered a few.
Thank you!
I just noticed that the proximity switch link brings up mostly "inductive sensors" -- they may not work with water. The link I posted for mine points to capacitive sensors and they do work with water, through plastic. I use several different kinds that I purchased from salvage shops.
I think "one person" would object to nearby power lines because of the E-M radiation but thinks nothing of keeping a iPhone in their pocket. How can you affect the water by squeaking at it?
My first attempt would have been temperature based. Put some LM335 temperature sensors in a line down the side of the tank. Maybe as few as three. But the capacitive sensor sounds great.
There is a saying: "You can't argue with crazy"
he doesn't have internet at his house because "they" can see into your house thru anything that is online...
Nice idea about temp (that's how I have a propane sensor). I think a black plastic tank out in the open would have problems with un-even solar heating as the sun moved (vs a white protected from sun propane tank) -- I think the capacitive sensors sound perfect & easy. I'm thinking of saying "they align the water molecules proven to help against cancer" (like the magnets on your fuel tank that align the gasoline to improve mpg's)
40khz is the known perfect frequency to kill microbes & bacteria, don't you know that? but who wants all that dead stuff in your drinking water?
One way the government spies on you is by detecting your conversations through vibrations transmitted through the water (much like the laser beam reflections off a window pane being monitored for frequency deviations). the isotonic warbulators in the "cap sensors" emit contrasting frequencies to mask the original vibrations,., with no known affect upon the water supply. Get yours now, before the government makes them illegal!
If he buys that, I have a vast array tin-foil hats for sale, which can be used for defeating microwave brain probing,,,,,
Have you seen the season finale of "Better Call Saul"? Where the character who believes anything electronic hurts him. He encased one room in tin foil. This guy has his "safe room" that consists of some cans of food, a porta-potty, a shotgun & is lined with crinkled tin foil "It can't be smooth, they can see thru smooth, it's got to be wrinkled and uneven"
I didn't see any hats, so I'll let him know.
MIT (I think - some well regarded school) students a while back studied the usual tinfoil hat, and found that it would actually act as an antenna at certain frequencies. Obviously they hit on something big, which is why none of you all have heard of the study - the only explanation is that the tinfoil hat was a rumor started by the world government's mindcontrol agency to trick those who had recognized the existence of their scheme to amplifying the mind control signal. Of course, the mind control drugs they put in the water and air (chemtrails) have to a great extent reduced their need for eletromagnetic mind control anyway.
Anyway, I should take this hat off now... Aaaah, that's more like it... So as I was saying, I wonder if you could just use cap proximity sensors meant for user interfaces for that? (hey, I make a breakout board for the mtch101...
I would get a radioactive isotope and place it on one side of the tank. Then place a geiger counter on the other side. The count will drop when there is water in between.
You could suggest this to your neighbour if he objects to the capacitave sensor. I have also used these and while they are quite pricey they do work if you can get it in contact with the tank on the outside.
In case this might sound far fetched to you this is exactly what we did in the 60s at one place I worked at for detecting the level of molten iron in a blast furnace.
@DrAzzy: great idea; I think I have a breakout for the mtch101 -- Easy enough to try with a plastic glass of water. @Grumpy_Mike: Ooh, I like it... I mean, the radioactive isotope would probably help sterilize the water too -- not to mention the large "Radioactive" sign we'd have to place to keep people away from dropping mind control drugs into the tank...
For some reason I'm reminded of a Russian move "How I ended this summer" (worth seeing, and only minutely related....)
Regulations on gamma sources are so strict today. The changes due to someone stealing the minute cesium source to build a dirty bomb have caused in most places to require a specific license that entails having a certified radiation safety officer and a lot of paperwork, inspections and of course ALARA, (as low as reasonably achievable) to prevent unnecessarily exposing the public to ionizing radiation.
I used the proximity type of sensors 30 years ago in mixing vats. They worked well then and there is no reason they will not work today.
If a nuclear gauge is your choice and you need a RSO (radiation safety officer), feel free to give me a call. I have more than 200 hours of classroom and more than 4 years of teaching radiation safety and 10 years in the repair of nuclear gauge tools. BTW, the low emissions of gamma ray will not sterilize.
