water/fuel mixture detector

[thabit ahmada]

i want to design a circuit which will detect pressance of water in a water/fuel mixture.i want to use the idea of conductivity or ability of light to penetrate on those liquids.

 

[spuffock]

I assume the fuel to be oil or petrol, something not miscible with water. Water has a dielectric constant much higher than most substances, so if the fuel/water mixture is made the dielectric of the tuning capacitor of an oscillator, then the oscillator frequency will be lower the greater the proportion of water. Theres something to experiment with,for a start.

 

[bogdanfirst]

what about a simple test of conductivity between 2 electrodes?
a square wave can be used to avoid corrosion due to electrolisis(if d.c. is used).
i have a circuit like this used to detect water. might work for this too. the circuitis quite simple.

 

[Noggin]

here is a senior design document dealing with that. If you look at the very end in the future work section you'll see that they finally setteled on testing for capacitance of the oil/water mixture.

https://www.electro-tech-online.com/custompdfs/2003/10/desdoc.pdf

Their final document is here. I know nothing more about the project, I haven't read their document or anything, but I assume it shows exactly how to build one.

https://www.electro-tech-online.com/custompdfs/2003/10/desdoc-1.pdf

In the next link, you'll be able to find the source code for the controller as well as everything else they've done.

https://www.ece.msstate.edu/classes/design/ece4522/2003_spring/water_detector/