At the bottom of the tank put a stretchy membrane (urethane resists petrol?)
and place 3 micro switches below/beside it (depends on where the hole is,
bottom/lower side of tank).
Put a little fuel in the tank and clamp #1 micro switch so that it is just
open.  You have a near empty indicator.
Put more fuel in the tank and clamp #2 micro switch so that it is just open.
You have a part full indicator.
7/8 fill tank and clamp #3 micro switch so that it is just open.  You have a
near full indicator.

Debounce the switches with a L O N G G G G delay.

Bye.

-----Original Message-----
From: Dave VanEe [mailto:dvanee@MECH.UBC.CA]
Sent: Friday, 21 September 2001 15:17
To: PICLIST@MITVMA.MIT.EDU
Subject: [EE]: Conductive Liquid Sensor


Hello,
I'm trying to make a simple fuel level indicator for a fuel tank.  I only
need to be able to sense a few levels (i.e. Full, ~1/3 full, Near Empty).
I'm thinking of having two wires (or other electrical contact) actually -in-
the gas, and using the fuel to "close the switch".  I'm pretty sure this
would work for water, but I don't know if the gas will be able to conduct
electricity well enough.  There is also the ignition issue, but at the
voltages I'd use it shouldn't matter.  I will be using 94 Octane gasoline
for my purposes.

Does anyone have any idea if this would work, or possibly have another
suggestion?

Thanks,
Dave

PS: I will be putting some gas in a container and checking the resistance w/
a multimeter to test it myself, but there might be a better solution.

--
http://www.piclist.com hint: The PICList is archived three different
ways.  See http://www.piclist.com/#archives for details.

--
http://www.piclist.com hint: The PICList is archived three different
ways.  See http://www.piclist.com/#archives for details.