Measuring fuel level thru a metal tank

Hi -- Is there a way to measure fuel (gasoline) in a steel tank? I was hoping there's a way to use an ultrasonic sensor glued to the tank, but so far have not found something that will work thru steel.

Pour hot water down the outside of the tank and run your fingers up the wet area.

Below the fuel level, the tank will stay cold. Above that, it heats up.

jremington: Pour hot water down the outside of the tank and run your fingers up the wet area.

Below the fuel level, the tank will stay cold. Above that, it heats up.

They have little strips you can stick on your propane tank to do the same thing. Liquid crystal, I think.

dougp: They have little strips you can stick on your propane tank to do the same thing. Liquid crystal, I think.

Too bad that link is broken :-(

The link works for me. Here it is raw: http://www.organizeit.com/accu-level-magnetic-propane-tank-gauge.asp

It seems that web site itself is just broken. I get to see a mostly blank page, with text:

ADODB.Recordset error '800a0e78'

Operation is not allowed when the object is closed.

/findcountry.asp, line 40

Not something I call useful content :) The page title does seem to be correct. Oh well, too bad.

wvmarle: It seems that web site itself is just broken. I get to see a mostly blank page, with text:

ADODB.Recordset error '800a0e78'

Operation is not allowed when the object is closed.

/findcountry.asp, line 40

Not something I call useful content :) The page title does seem to be correct. Oh well, too bad.

Same here, WIN7, Chrome. Tom.... :o :o :o

daveyjones: Hi -- Is there a way to measure fuel (gasoline) in a steel tank? I was hoping there's a way to use an ultrasonic sensor glued to the tank, but so far have not found something that will work thru steel.

Use the same method the professionals use: take the cap off and use a wooden stick. Or take the difference between what you purt in and what you have taken out.

Paul

For those interested the description is: Accu-Level Magnetic Propane Tank Gauge. It's available at many websites.

Somebody's done it. Turck's new levelprox

dougp: For those interested the description is: Accu-Level Magnetic Propane Tank Gauge. It's available at many websites.

Basically the same as the suggestion in #1 but without the need of using fingers to sense the temperature.

Out there idea: I guess you could get a handful of LM35's and stick them to the tank and read the outputs with an analog mux. An electronic version of the visual stick-on tape method. It would need some refinement.

Will there be any significant differences in temperature without external heat source?

Just thinking of ultrasound... now we're going the crazy ideas route... there may be another way to do it: hammer and microphone. Have the hammer hit the tank, and the microphone pick up the sound of the resulting "boing". The frequency of this sound related to the size of the cavity in the tank, which in turn tells you how much fuel is in there - the larger the cavity, the lower the tone.

wvmarle: there may be another way to do it: hammer and microphone. Have the hammer hit the tank, and the microphone pick up the sound of the resulting "boing". The frequency of this sound related to the size of the cavity in the tank, which in turn tells you how much fuel is in there - the larger the cavity, the lower the tone.

I wonder if that's the technique applied in post #9?

dougp: I wonder if that's the technique applied in post #9?

Unsure - the description mentions it's using ultrasound, maybe looking for echos and how fast they come back to tell the levels? No further details so that's just my guess. My idea was more in the lines of agitating the tank rather violently and see what frequency comes back (usually not ultrasound).

You could also generate a raising sine wave sound with one speaker element attached to one side of the tank, while a microphone at the other side detects the strength of the sound at the same frequency. Different amounts of liquid give different shaped envelopes of the received sound. This would need learning.

The only successful method i've heard of, is ultrasonics from the top and f the tank... looking for the reflection off the surface (radar!) ... or of course, a float.

For years, I have been using pressure sensors on rainwater tank outlets to keep track of water level.

As long as there is no flow, the pressure is directly proportional to the height of the fluid in the tank. This works with any fluid.

Those solutions require a hole in the tank (if only to get the wires out) and it seems OP didn't want to do that, even though it seems his tank is not even pressurised.