I am looking for a safe way to measure the level of water in two kind of tricky locations. Any suggestions on what to use as a sensor would be awesome.
• 5 Gallon Jug inside of a bottom load water dispenser
• Water level in my pet’s bowl. (Link Below, it’s neat)
I’ve looked at liquid level sensors, they don’t seem to be what I need. I’ve looking into the waterproof ultrasonic sensors, but I don’t have the slightest bit of clue how these work, I’ve checked a couple of videos, but I’m left with questions, do they go into the water, need to be in the tank, or can they get a reading on water levels from the outside of the container? It looked to me like they were using them to tell the levels in a a propane tank?
Ultimately I think I may end up load sensoring them and just calculating percent by weight, and maybe figure out how to convert to other measurements from there, but really, I need percent. Any other ideas?
I think that’s what I would do.
the pet watering bowl doesn’t look like it’s design would allow to put any type of water sensor in there.
I use load cells and an ESP8266 with ESPHome to measure the weight of the propane tanks for my grill and smoker and they work pretty well. They give me weight that I can then convert to percent.
I’m always looking for a better way to detect water, fuel and wastewater tank levels. Load sensors could work in some cases, like the propane tank example. Which got me thinking…
Would some kind of pressure sensor work? Obviously the pressure at the bottom of the tank increases with the tank level. Maybe the reason I haven’t heard of this is because it’s impractical.bb
Just thinking about the pet watering bowl, when using a pressure or weight sensor probably won’t work when your pet is drinking, because these values will be effected, right?
Thinking out of the box, could a moisture sensor be something you could use? FYI, I don’t have any experience with moisture sensors though…
For example, in industrial environments tank levels are done several ways:
1 - Pressure sensors, bottom-up, because of direct contact to the medium it must not contain fluids which affect the sensor membrane (like chemicals or sludge).
2 - Radar sensors, top-down, do have problems with floating foam or fast medium turbulences (i.e. when agitators are used).
3 - Weight sensors, must have a stable construction and can be sensitive to ambient vibrations (i.e. heavy machinery, traffic vehicles)
4 - Capacitive level sensors, top-down, same cons as pressure sensors.
5 - Laser sensors, top-down, can be effected when lenses are polluted.
6 - Level switches, commonly used as safety (overflow, empty tank detection) or filling tanks by fluid pumps (i.e. start filling the tank by 10%, stop filling at 90%). An example is your toilet reservoir.
Just FYI…
EDIT: just forgot, there are also ways to detect levels, outside a tank, by use of ‘communicating vessels’ (level tubes and bubble tubes).
EDIT2: be very aware of the use with gasses/flammable/explosive environments (ATEX, formerly known as Ex)!! (use of an intrinsically safe Voltage/Amperage)
Lots of great info here. I will probably go load sensor then. The solution for if they are drinking it is to set time parameters on the automations for state, I’m not as concerned about graphing it, though the spikes in the graph would indicate when they are drinking it.
it could for a larger tank but in a 5 gal jug and especially a small pet bowl the pressure differential from atmospheric would be so low that you would need a REALLY sensitive pressure transducer in order to measure it if it was even possible.
Just a suggestion for the 5 Gallon Jug (+/- 19 litre), by using the ‘communicating vessels’ principle…
You could try, if this is possible, insert a small flexible hose or pipe near the bottom and with a curve as high as the upper water level, and do the detection of water level on a place where you have more room to experiment/install an ESP32 and sensors.
And of course, please share you findings! 
So… this is a genius idea, no joke. I may screw around with it.
Thanks for the compliment, makes me blush 
I’m looking forward to your findings! 