> >        I'm looking for a humidity sensor.
> >        Anybody know?
> >        Thanks
> >        Ricardo
> >        rcbarbosa@riopreto.com.br

Probably not what you're after, but I have had some success with the
following design, which uses wet-bulb/dry-bulb measurements along with
a table of wet-bulb depression implemented by a microproessor.

Two NSC temperature sensors are used (LM335Z I think).  These look like
zeners whose breakdown voltage is proportional (10mV/K) to absolute
temperature.  The output is 2.73V for 273 Kelvins.  A pair of op-amps
is used to measure the absolute temperature indicated by the dry
sensor, and the difference in temperature between dry and wet.  The
signals are converted into current sources which are remotely sensed by
resistors, and the resulting voltage fed into a multiplexed ADC.  The
microprocessor converts the readings into temperature and relative
humidity by looking up a table and interpolating where necessary.

The wet sensor is kept moistened by a wick.  Of course this is probably
too inconvenient for most practical applications, but does have the
advantage of not requiring calibration.  Also, the parts are very easy
to find.

Regards,
SJH
Canberra, Australia