electrodes used in water

In article <1129951786.836219.262790@g47g2000cwa.googlegroups .com>,
hariesy@yahoo.com wrote:

I am designing a micro controller based Water level controller.
but the electrodes wht I am inserting inside the water to detect the
water level will under go into chemical reaction.Thus after a few days
the metal wht I have dipped inside the water will be vanished living
some residues and hence plz some body suggest me wht kind of material
should I use to solve this problem.

Very expensive platinum.

Or else use a float mechanisim inside of a glass tube. Detect the
position of the float in the glass tube. Since you didn't supply
details, I'm assuming stationary, standard room temp./pressure operation.

Al

On 2005-10-26, Al <no.spam@wanted.com> wrote:

I am designing a micro controller based Water level controller.
but the electrodes wht I am inserting inside the water to detect the
water level will under go into chemical reaction.Thus after a few days
the metal wht I have dipped inside the water will be vanished living
some residues and hence plz some body suggest me wht kind of material
should I use to solve this problem.

Stainless Steel lasts fairly well and is much cheaper than gold or platinum.
that's what they use in swimming pool chlorinators.

on the other hand if you encapsulate the electrodes in some insulating
membrane and measure the capacitance between them you'll detect a
signifcant increace in capacitance when there's water between them.

or you could attach a magnet to a float and use a reed switch etc to detect
the level.

Bye.
Jasen

"Jasen Betts" <jasen-b@free.net.nospam.nz> wrote in message
news:iu2h33-b5b.ln1@news.compass.net.nz...

On 2005-10-26, Al <no.spam@wanted.com> wrote:
I am designing a micro controller based Water level controller.
but the electrodes wht I am inserting inside the water to detect the
water level will under go into chemical reaction.Thus after a few days
the metal wht I have dipped inside the water will be vanished living
some residues and hence plz some body suggest me wht kind of material
should I use to solve this problem.

Stainless Steel lasts fairly well and is much cheaper than gold or
platinum.
that's what they use in swimming pool chlorinators.

And even better: remove the cause of this electrolysis. He is obviously
measuring with a DC voltage, which causes electrolysis. Measuring with an AC
voltage prevents this. Also, carbon electrodes (pencil fillings) work well.

Meindert