Round water tank level sensor

[breimann]

@Boots33 Excellent. Thankyou.

[MasterCATZ]

very interesting and another Aussie, QLDer here

[Denverado]

Hi there. I am currently making the exact same project using a RPi3 and a JSN-SR04T ultrasonic sensor. My tank is 2 meters tall and are currently having issues with the sensor giving echos off the side of the tank. Did you have any issues like this? Im a SE Qlder as well.

[Boots33]

Hi @Denverado

It seems water tank projects are popular down under.

As to echo issues I have had no problems to date. I still have not had the tank bellow 80% though so can't yet tell if there may be issues. Ultrasonic sensors have been used commercially for tank level indicators so I think we should be ok.

As I noted in the first post a good 5v supply is essential for stable results. You could also have a look at this post it would seem that others have had some trouble with the JSN version as well.

Are you certain it is echo problems, what sort of readings are you getting? I know you can get sensors with a narrower beam but they usually cost a lot more too.

[Denverado]

@Boots33, the readings I am getting are consistent..... they are just consistently wrong. :( I am going to try and install the sensor in a tube and see if that helps.
Fingers crossed!

[zboblamont]

@Denverado If this is a JSN-SR04T-2.0, as @Boots33 has already alluded to, now is a good time to take up religion. Spent a further 5 hours this afternoon trying all manner of variations of pullup resistor and sketch configurations per only available info and came up nada... Good luck... It is a veritable Chinese puzzle....

[Denverado]

@zboblamont I don't have a problem with my sensor. It works perfectly. It just casts a really wide beam. I'm estimating around 60 degrees!!! Has anyone tried changing the variable inductor on the unit to see if the beam can be narrowed?? Or does anyone have a schematic of the unit, as I have a friend who is an electrical engineer and might be able to help?

[Denverado]

@zboblamont I got mine to work by following the instructions from this guy. I also found the following drawing. . So my therory is if you change the variable inductor. You should be able to narrow the beam..... just a therory. If someone wants to try it... im happy to hear the results.

[Denverado]

@Boots33 Sorry mate I have kind of taken over your thread! The project looks great. I might have to try the same sensor as you.

[Boots33]

@Denverado Not to worry, I like the use of the voltage divider in the article you linked to. Always room for more ideas.

[zboblamont]

@Denverado For clarity, you mentioned previously your sensor was the JSN-SR04T, I was referring to it's modern incarnation the JSN-SR04T-2.0. Although advertised as the former, it was the latter which was delivered. Another guy found no problem with the original either, until he got the 2.0, which seems to be a bit of an enigma.

[Denverado]

@zboblamont I have the 2.0 as well.

[zboblamont]

@Denverado The puzzle continues then... I could not get it to work at all even having read through your linked post and meticulously following every step. All very strange...

[zboblamont]

@Denverado I would intrigued if the electrical configuration of a transducer could influence it's formation of an ultrasonic cone as I understood this to be down to the emitting diaphragm thereby physical), but my only experience of ultrasonics was in the water industry where we would confine the transducer in a pipe to negate offside reflections to measure distance to a surface. The objective was to hit still fluid which was the shortest echo path back to the receiver. The shortest route was the trigger....

[Huw Thomas]

I've been searching online for a project like this and it looks great. I'm doing something similar with an oil tank and have everything up and running, but the sketch I'm using is really basic, it just returns distance to oil level. Is it possible to change your sketch to allow for a rectangular tank, rather than cylindrical?! I'm an absolute beginner when it comes to coding unfortunately so any advice would be great. Thanks.

[zboblamont]

@Huw-Thomas Not so much a coding issue Huw, it's basic mathematics once you have the depth to surface and the cross section is a constant over the range.
You will know or be able to measure the height from the sensor head to the outlet and the full mark. Everything between is a proportion of height multiplied by floor area whether it is capacity or spare capacity...

[gohan]

@Huw-Thomas it's basic geometry 😀

[Huw Thomas]

Yes I realise that , I just wasn't sure at first where I needed to change things in the sketch. I think I've worked it out. I have zero experience in reading programming code so couldn't at first find the PiR^2h equation to change it, but now I've found it.

[Boots33]

@Huw-Thomas Sounds like you are heading in the right direction.
The water percent available calculation should work unaltered for a rectangular tank and you have already found

waterAvail = PI* pow(tankRad,2)*(((fullHeight-outletHeight)+sensHeight)-pingHeight)/1000;    // calculate water available in litres

That is the line that will need the change with the suggestions from above.

[Lawrence Helm]

@Boots33 Have you thought about sending the days available. i.e. calculate daily usage and divide that by the water that is still available? would have to roll the numbers i.e. say take the last two weeks of how much the water dropped in a day averaged out... if that makes sense. :)