I need to create a project in which is needed to measure the level of a tank fueal.
(the height of the tank is around 5m).
I don't know what method/sensor need to be used for measure the level of the tank.
I need your advise please.
I've seen a number of users on here use ultrasonic modules for this. Basically the transducer is placed inside the lid of the tank. The ping is reflected from the surface of the liquid in the tank. The distance to the surface of the liquid can then be simply calculated (to within about a centimeter) and, by deduction this tells you how full your tank is.
Needless to say make sure there are no loose connections to cause sparks! 
Weedpharma
Sonic rangers will do. I have a project that does this, open flume, so there is little reflection from side of tank.
Just a weird idea, but could you use the resonant frequency of the tank to tell how full it is?
Think of a "glass harp." The fuller the glass, the higher the frequency.
see Glass harp-Toccata and fugue in D minor-Bach-BWV 565 - YouTube
I've no idea how you would implement this, though.
How about blowing across the top of it and measuring the frequency of the whistle?
Nick_Pyner:
How about blowing across the top of it and measuring the frequency of the whistle?
With a 5m deep tank that "whistle" is going to wake the entire neighbourhood 
put in a boat, use a microphone. the louder the sounds of the sea shanties, the closer the crew is to the microphone.
carefule attention to calibrating rum dispersal uint is in order lest the volume increases moure than the level.
OK, you guys. No need to take the piss. I did ask if it could be done that way.
In industrial applications ultrasound or radar is mostly used. Then there are a number of projects that use capacitive sensing for fuel gauges. Just two twisted wires and measure the capacitance between them. Only hardware required are the wires and some resistors
A float in the tank, rope through a pulley at the top, counter-balanced to a sensor outside near ground level...easy.
Sorry, what is your fueal,
is water or oil?
how the special conditions need concern, such as measure risk of deviation?
any images upload will help forum guests to find your better answer.
Rubix-Arduino:
Sorry, what is your fueal,
is water or oil?
how the special conditions need concern, such as measure risk of deviation?any images upload will help forum guests to find your better answer.
I have not seen any reputable claims of water being a fueal or even as fuel.
Weedpharma
it uses an ultra sonic sensor, then with wireless sends the values.
same thing, home brew
Henry_Best:
Just a weird idea, but could you use the resonant frequency of the tank to tell how full it is?
Think of a "glass harp." The fuller the glass, the higher the frequency.
see https://www.youtube.com/watch?v=XKRj-T4l-e8
I've no idea how you would implement this, though.
interesting idea. you could put a pipe, like a tuning fork, into the tank, and vibrate that. the harmonic resonance will change with the level of the liquid. and since there is no electronical bits in contact with the solution, it would be intrinsically safe.
darn... I was hoping to get in on the testing and calibration of that 'rum dispersal unit"
"In industrial applications ultrasound or radar is mostly used. Then there are a number of projects that use capacitive sensing for fuel gauges. Just two twisted wires and measure the capacitance between them. Only hardware required are the wires and some resistors"
Where can i find suitable ultrasound/radar sensors or capacitive sensing for fuel gauges for this application ?
Tom1111:
Where can i find suitable ultrasound/radar sensors or capacitive sensing for fuel gauges for this application ?
Just google "arduino ultrasonic module" They're really common. I'd suggest you use some potting compound on the sensor leaving just the horns exposed. Put your arduino on the outside of the tank in a separate box.
with the term of "capacitive sensing for fuel gauges" is the use of something like the car's Fuel Gauges ?
two prongs project down the tank.
There are two dielectrics the air and the fuel.
The capacitance varies as the fuel level increases
cars use a float and pot.
Hi,
Tom1111, yes as you say, there are capacitive car fuel level sensors out their, we have had them in fords in Australia since the mid 70's
I'm surprised no one else has shown this, surely in the US, Ford must have them, or are they an AUSTRALIAN invention, and the US hasn't caught on yet? (Sorry US bashing in fun, sarcasm... ;))
Tom......