Hi Vasile,

What method are you using to determine the accuracy of a humidity sensor?

/Ruben


> Thx for the links.
> What I know for sure is that measuring precisely the RH is not a piece of
> cake.
> There aren't many humidity sensors on this world with an accuracy less
> than 2-3%RH and
> based on physics laws, measuring accurate the RH means also an
> accurate temperature measuring because there is a tight corellation
> between those.
> I've tested SHT75 which is the most precisely factory calibrated RH
> sensor from Sensirion. It's not so good like datasheet said. So again,
> do not believe datasheets utill you've tested the device as the
> measuring rules said. A datasheet is just a piece of paper, nothing
> more.
> =

> On 8/4/07, Rich <rgrazia1@rochester.rr.com> wrote:
> > http://www.jlcinternational.com/articles/humidity_sensor_elements_info.=
htm
> >
> > ----- Original Message -----
> > From: "Vasile Surducan" <piclist9@gmail.com>
> > To: "Microcontroller discussion list - Public." <piclist@mit.edu>
> > Sent: Saturday, August 04, 2007 7:47 AM
> > Subject: Re: [PIC] low cost to measure R/Humidity ?
> >
> >
> > > On 8/4/07, cllow2020 <cllow2020@163.com> wrote:
> > >> Is there a low cost RH sensor measurement method for long distance?
> > >>
> > >> As far as I know, DEW sensor (
> > >>
> http://www.electronic-circuits-diagrams.com/sensorsimages/sensorsckt2.sh
> > >> tml ) for logic on/off. But capacitive method is another liner
> > >> measurement refer to Measure humidity and temperature on one TTL line
> > >> http://www.edn.com/contents/images/83001di.pdf , my question is how
> long
> > >> can the TTL signal line go ? 50m ?
> > >
> > > Transform the TTL into a differential signal (LVDS or 5V
> > > differential), use a CAT5 twisted pair and you'll go more than 50m.
> > > The problem is that solution is not very precisely one. If you accept
> > > any RH error of more than 5% then it's ok.
> > >
> > >>
> > >> Any input ?
> > >>
> > >> Regards
> > >> cllow2020
> > >>
> > >> No virus found in this outgoing message.
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> > >> Version: 7.5.476 / Virus Database: 269.11.0/927 - Release Date:
> > >> 7/30/2007 5:02 PM
> > >>
> > >>
> > >>
> > >>
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