Hi,

I'm constantly having trouble with pressure switch of a water pump,
which is supplying water from a well for a house and garden. Setup is
far from optimal, and seems like normal, membrane-activated switches
are having trouble with this. I am sure there are better switches
available somewhere, but I had an idea to build one by myself, using a
PIC. That way I could have better control of ON and OFF pressures, and
hysteresis, probably also some kind of dynamic self-adjusting, to cope
with completely different situations of supplying just home, vs
supplying water for garden. Soft start of a pump motor could be
implemented easily too.

Any ideas what cheap pressure sensor could be used? Sensor has a
direct contact with water.
Some kind of a digital output would be best, but i can live with
analog signal too.
Best if that sensor is widely available, that is, used in some
consumer equipment.

Somebody recommended to use oil pressure sensor from a car, that has
continuous-signal sensor, not just a pressure switch, but I do not
have an exact car model that uses this kind of sensor.
Probably sensor, designed to contact with oil, would not live very
long with water, but it's ok to replace it sometimes if it's cheap
enough.

I'm interested in pressures between 1 and 6 bar, or so.

--=20
KPL
--=20
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