I suggested the same idea with the optical sensor's but use a mirror on
bottom of tank so all electronics is out of tank and in one area. Use of
slush tube with holes would help also as suggested by others.
Wrong Way Ray  (Raymond Choat)

----- Original Message -----
From: "Andrew Hooper" <andrew@BEST.NET.NZ>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Monday, September 24, 2001 2:17 AM
Subject: Re: [EE]: Conductive Liquid Sensor


> Why not just use optical sensor's?
> Seems to me that the depth of the fuel could be calculated by the amount
> of light able to penitrate.
>
> Top of tank with led or ir emitter
> |----\_/----|
> |~~~~~~~|
> |----/^\----|
> bottom of tank with ir receiver.
>
> Or another alternative is an ultrasonic sensor in the top.
> most industrial ultrasonic units are stainless and work well in fluid.
>
> Or cheap and nasty, pezio transducer stuck to one side of the tank
> on the other side a mechanical hammer, strike the tank and pickup
> sound vibration from the pezio. :) need better resolution then install
> a bigger hammer :)
>
> Andrew
>
> > I've been a bit disturbed by the number of people
> > advocating using electricity in contact with the
> > fuel...
> >
> > I have a lot of circuit diagrams for modern vehicles,
> > and often advise people re installing equpment or
> > modifying these modern vehicles. It's part of my
> > job. :o)
> >
> > I see NO modern vehicles using electricity in direct
> > contact with the fuel!!!!
> >
> > The 3 main types of fuel level sensing in modern
> > vehicles are:
> >
> > * Simple pressure gauge (senses liquid height above
> > the pressure sensor)
> > * Sliding float over sealed tube with reed switch.
> > * Thermistor sensor (senses difference in heatsinking
> > between fuel and air)
> >
> > ALL of these 3 types have one thing in common, there
> > is NO direct contact between fuel and electricity.
> >
> > Call me a safety freak if you must, but I would NEVER
> > consider using live electricals in contact with fuel.
> > If the fuel container is punctured, and some atmospheric
> > condition causes the fuel to atomise, you have real
> > danger situation presented.
> >
> > Surely if the cost/hassle of contruction is similar,
> > you MUST prefer a system with no direct electics
> > in the fuel??
> >
> > Please argue if you think i'm wrong, or argue with all
> > the modern vehicle manufacturers if you like...
> > -Roman
> >
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