Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!swrinde!elroy.jpl.nasa.gov!lll-winken!hpuplca!jeff From: jeff@hpuplca.nsr.hp.com ( Jeff Gruszynski ) Newsgroups: sci.electronics Subject: Re: Humidity Sensors in Clothes Dryers Message-ID: <12780001@hpuplca.nsr.hp.com> Date: 12 Apr 91 23:58:26 GMT References: <1991Apr12.113251.16467@minyos.xx.rmit.oz.au> Organization: Hewlett-Packard Pleasanton Ca. Sales Lines: 37 * / hpuplca:sci.electronics / s882823@minyos.xx.rmit.oz.au (Scott Reynolds [.../* sbr */...]) / 4:32 am Apr 12, 1991 / * I have a question hopefully someone out there in net-land can answer? * * We (a group of 17 Electronic Eng 3rd Year Students) have a 12 week * design project for designing a Micro Controller for a domestic * clothes dryer. After extensive market research (looking in the * local dept. store) found that humidity controlled dryers were * 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 * * * Any suggestions/reply would benefit 17 frustrated Eng Students * (and probably give 'em a better mark too!!!!!!!) * * Thanks * * Scott Reynolds * 4th Year Electronic Eng/Computer Sci. Student RMIT Aust. * ---------- I would strongly recommend using Thomas Catalog for this search. It's available at most libraries. A set of green monstrosities! Look under Humidity Sensors. I know there's a company called 'Omega ' (not, apparently, related to the thermocouple people in Conn.) that makes them. Somewhat pricey, ~$30/sensor, with each sensor only giving about 15-20% RH range. Not spectacular dynamic range. They can be poisoned fairly easily by things like sulfur compounds and liquid water. There are special ($) teflon coated versions. Last I talked to them they accepted only POs or CODs. Jeff Gruszynski Santa Clara Sales Hewlett-Packard