You don't say how deep the tank is, etc, but the cheapest way (free) is the
water level sensor from any old washing machine. There are normally two
switches in there for a full level and a rinse level, (and they last forever)

Since the switches operate on a really low pressure, you can
configure/alter the depth/hysterisis by changing the tube thickness or
including small air reservoirs/pockets in the tubing system .

Regards
Roland

At 08:35 PM 08/06/04 -0700, you wrote:
>Hi All,
>
>I have a tank with a submersible pump inside, I want to stop the pump from
>running dry when the water level is too low, what sort of sensor could I
>use? I'm thinking of using a float with a magnet attached, the magnetic
>field will trigger a relay to turn off the power, does anyone get experience
>in building this kind of thing and would like to share the experience with
>me?
>
>Thanks in advance!
>
>John
>
>_________________________________________________________________
>Tired of spam? Get advanced junk mail protection with MSN Premium
>http://join.msn.com/?pgmarket=en-ca&page=byoa/prem&xAPID=1994&DI=1034&SU=ht
tp://hotmail.com/enca&HL=Market_MSNIS_Taglines
>
>--
>http://www.piclist.com#nomail Going offline? Don't AutoReply us!
>email listserv@mitvma.mit.edu with SET PICList DIGEST in the body
>

--
http://www.piclist.com hint: To leave the PICList
mailto:piclist-unsubscribe-request@mitvma.mit.edu