The humidity sensor is actually a Honeywell part. The Maxim/Dallas part is =
a =

battery monitor circuit with, amongst other things, an A/D converter that i=
s =

used to measure the output voltage of the humidity sensor. The Maxim/Dallas =

part also has an integrated temperature sensor that is used to calculate th=
e =

actual R/H from the Honeywell sensor.

This way you get a neat R/H sensor with a 1-wire interface.

/Ruben

> Vasile, did you look at the Dallas-Maxim part? =

> http://pdfserv.maxim-ic.com/en/an/humsensor.pdf
> =

> ----- 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 lo=
ng
> >> 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.
> >> Checked by AVG Free Edition.
> >> Version: 7.5.476 / Virus Database: 269.11.0/927 - Release Date:
> >> 7/30/2007 5:02 PM
> >>
> >>
> >>
> >>
> >> --
> >> http://www.piclist.com PIC/SX FAQ & list archive
> >> View/change your membership options at
> >> http://mailman.mit.edu/mailman/listinfo/piclist
> >>
> >>
> > -- =

> > http://www.piclist.com PIC/SX FAQ & list archive
> > View/change your membership options at
> > http://mailman.mit.edu/mailman/listinfo/piclist =

> =

> -- =

> http://www.piclist.com PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist
> =


=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D
Ruben J=F6nsson
AB Liros Electronic
Box 9124, 200 39 Malm=F6, Sweden
TEL INT +46 40142078
FAX INT +46 40947388
ruben@pp.sbbs.se
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D

-- =

http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist