Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!abvax!iccgcc!gibbonsj
From: gibbonsj@iccgcc.decnet.ab.com
Newsgroups: sci.electronics
Subject: Re: Humidity Sensors in Clothes Dryers
Message-ID: <4348.2815ab67@iccgcc.decnet.ab.com>
Date: 24 Apr 91 20:59:35 GMT
References: <1991Apr12.113251.16467@minyos.xx.rmit.oz.au> <1991Apr17.161514.756@eagle.lerc.nasa.gov>
Distribution: sci.electronics
Lines: 28

stuff deleted
>> 
>>We (a group of 17 Electronic Eng 3rd Year Students) have a 12 week
>>design project for designing a Micro Controller for a domestic
>>rare - hence our desire to use the exhaust air humidity as a indication
>>of the dryness.
>> The problem arises as to selecting an appropriate sensor, considering
>> the nasty environ.
>> Does anyone know of sensors used in commerically availiable products

Another problem you will run into is that in gas dryers, the normal by-product
of the combustion process (of natural gas) is water vapor, so hudmidity sensors 
in gas dryers are not very useful.  You could look at the relative hudmidity at 
the beginning of the drying cycle and then compare it to what you normally see 
at the end of the cycle, but you would run into problems on high-humidity types
of days (you might think that the relative hudmidity would not drop enough
to consider the load of laundry being dry).

Good luck on your project - and beware of the static electricity that is created
by overdrying a load of laundry (you know, 'static cling'...).  One zap from 
that will completely destroy a micro system...

-- 
  John Gibbons                                       Cleveland, Ohio

           "Welcome My Son, Welcome To The Machine" - Pink Floyd

           Of all the things I've lost, I miss my mind the most...