What is used for sensing humidity?
in [Design]
|
Prev: Layout of RFID/NFC antenna?
Next: Short message
From: D Yuniskis on 23 Mar 2010 12:23 Hi Greg, GregS wrote: >> Aw, hell... you could probably just run the fan open loop >> or driven by temperature and get the sort of control you >> need. E.g., when you take a shower, the room tends to be >> humid. So, notice a "sudden increase" in temperature and >> use that to trigger the fan. > > Just get a ssssshhhh sensor. Water !! Ha! Yes! ;-) > Or motion or sound, just turn the dam fan on when somebody > is using the bathroom. Many homes have fan wired to light fixture *or* in addition to light fixture. But, that means you have to remember to turn it off, later. (timer? -- hence my suggestion "open loop")
From: Jim Thompson on 23 Mar 2010 12:24 On Tue, 23 Mar 2010 17:02:49 GMT, zekfrivo(a)zekfrivolous.com (GregS) wrote: >In article <hoao3s$lhp$1(a)speranza.aioe.org>, D Yuniskis <not.going.to.be(a)seen.com> wrote: >>Hammy wrote: >>> I've been goggling and all I've been finding is $50 to $100 plus, full >>> modules what is just the sensor used in for example dehumidifiers? >> >>The "cheapie" sensor is based on the fact that hair "grows" >>(stretches) up to 50% when wet (dry hair only stretches about 20%). >>Typically, animal hair is used (notably, horse). > > >You get good control around midpoint, but trying to set at 80% is hard. > > >> >>Aw, hell... you could probably just run the fan open loop >>or driven by temperature and get the sort of control you >>need. E.g., when you take a shower, the room tends to be >>humid. So, notice a "sudden increase" in temperature and >>use that to trigger the fan. > >Just get a ssssshhhh sensor. Water !! >Or motion or sound, just turn the dam fan on when somebody >is using the bathroom. > >greg Probably the most reliable... just make it a "pulse stretcher"... motion equals 20-30 minutes of fan time... fart clearance ;-) ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | The only thing bipartisan in this country is hypocrisy
From: Hammy on 23 Mar 2010 13:22 On Tue, 23 Mar 2010 17:02:49 GMT, zekfrivo(a)zekfrivolous.com (GregS) wrote: >Just get a ssssshhhh sensor. Water !! >Or motion or sound, just turn the dam fan on when somebody >is using the bathroom. > >greg Yea that's the ideal solution, are you coming over to rip out and replace all the drywall and then patch and repaint? It wouldn't be so bad but there is also a boxed in duct that blocks the routing for the logical placement of the switch;by the door and the light switch. I thought of just running it off the light switch but I don't really want the fan on every time the lights on. I can run a wire relatively easily parallel to a joist about six feet to a crawl space which has a light switch. That's where I can get power to the fan with minimum damage. I was just looking for a way to activate an SSR or relay to switch the fan on without having to go into the crawl space. I figured a humidity sensor could be used to trip a relay or SSR. I see digikey has these. http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=480-3166-1-ND
From: Spehro Pefhany on 23 Mar 2010 13:40 On Tue, 23 Mar 2010 17:02:49 GMT, zekfrivo(a)zekfrivolous.com (GregS) wrote: >In article <hoao3s$lhp$1(a)speranza.aioe.org>, D Yuniskis <not.going.to.be(a)seen.com> wrote: >>Hammy wrote: >>> I've been goggling and all I've been finding is $50 to $100 plus, full >>> modules what is just the sensor used in for example dehumidifiers? >> >>The "cheapie" sensor is based on the fact that hair "grows" >>(stretches) up to 50% when wet (dry hair only stretches about 20%). >>Typically, animal hair is used (notably, horse). > > >You get good control around midpoint, but trying to set at 80% is hard. > > >> >>Aw, hell... you could probably just run the fan open loop >>or driven by temperature and get the sort of control you >>need. E.g., when you take a shower, the room tends to be >>humid. So, notice a "sudden increase" in temperature and >>use that to trigger the fan. > >Just get a ssssshhhh sensor. Water !! >Or motion or sound, just turn the dam fan on when somebody >is using the bathroom. > >greg Flow sensor-- it will run from the time the toilet is flushed 'till the tank refills, without that annoying racket from the fan when you're in there trying to read EDN. ;-)
From: linnix on 23 Mar 2010 14:10
On Mar 23, 9:22 am, Hammy <s...(a)spam.com> wrote: > On Tue, 23 Mar 2010 17:02:49 GMT, zekfr...(a)zekfrivolous.com (GregS) > wrote: > > >Just get a ssssshhhh sensor. Water !! > >Or motion or sound, just turn the dam fan on when somebody > >is using the bathroom. > > >greg > > Yea that's the ideal solution, are you coming over to rip out and > replace all the drywall and then patch and repaint? It wouldn't be so > bad but there is also a boxed in duct that blocks the routing for the > logical placement of the switch;by the door and the light switch. > > I thought of just running it off the light switch but I don't really > want the fan on every time the lights on. > How about wireless? I am using wireless keychain remotes and RF receivers to run my hot water circulation pump. I will also install RF receivers to the fans later. I have not been able to decode the RF encoding, but at least can detect any button press. There are false positive and negative actions, but no big deal for me. |