Re: Not-too-conductive material
- From: dplatt@xxxxxxxxxxxx (Dave Platt)
- Date: Thu, 24 Jul 2008 22:01:49 -0700
Regarding the capacitance method: The normal insulation on regular hookup wire
is too thick to generate an easily-measured capacitance. I would need to get
into the RF spectrum to do it (I've tried), and this device is too
cost-sensitive to allow it.
How about enamel (Formvar, Polyvar, whatever...) insulated magnet
wire?
From the experiments I have done so far, the effective resistance between theprobes depends very little on how far apart the probes are, and much more on the
total conductive surface area in contact with the water.
How much spatial (vertical) resolution do you need?
If the answer is "not very much" you could fabricate the probes out of
a thin rectangle of PCB material (something water-resistant) with a
series of pads etched into it, and solder down to the pads a whole row
of SMT resistors (in effect, connected head-to-tail). You'd get a
discrete step in resistance each time the water rose high enough to
bridge a resistor. Choose the resistance per step to suit your needs.
Some sort of silk-screened conductive ink might also be a possibility?
--
Dave Platt <dplatt@xxxxxxxxxxxx> AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
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- Re: Not-too-conductive material
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