[Hunter’s] wife came home from her latest extreme couponing session with a handful of free Air Wick Odor Detect air fresheners, and since they had so many of the things sitting around, he was compelled to take one apart to see what makes them tick.
The casing was secured with melted snap tabs which had to be cut, making disassembly a one-way street. Once opened, he found a trio of white label AA cells and an ARNIE COMPACT3 ISS.4 controller board, complete with an epoxy-sealed microcontroller. A similarly branded sensor board was attached to the controller, and he spotted a solenoid with a built-in nozzle for spraying air freshener as well.
The sensor board piqued his curiosity the most, and after some research he’s pretty sure that the Air Wick uses an Applied Sensor VOC air quality module to get the job done. The tiny sensor uses a special substrate containing electrodes, which measure the resistance of the sensing layer while it is heated to upwards of 400° C. A change in resistance lets the air freshener know that it’s time to handle the odoriferous emanations floating about.
Thanks to [Hunter] for taking the time to tear the Air Wick down and letting us know what’s inside!
I love the term “human bio-effluence” in one of the documents he references about the sensor chip.
So, maybe we could use this sensor system to activate an exhaust fan system?
Arduino fart detector on my radar!
Just had a great idea: there are some toys that make a fart sound when you press a button. One could rig the solenoid from the detector to press a button when a fart is detected. So it’s a device that when it detects a fart smell pushes a button and makes a fart sound. Anybody that has a grandmom that throws some “silent killers” will understand the purpose of this alarm system.
In regards to the silent killers, an early warning alarm is is needed so one can get out of the way. By the time the device that activates, the other occupants already know what occurred. Besides grandma can always still proclaim her innocence.
You need a grid of the sensors placed around the room so that you can tell where the VOC originates.
done
http://www.instructables.com/id/The-Twittering-Office-Chair/?ALLSTEPS
I’m wondering if the sensor detects the odor of the air freshener…
very interesting… i see a “stink-o-matic” tazer in my future…
I’m curious if you could use this sensor (or same design, lower temperature) to detect alcohol on someone’s breath.
Would surely be a cheaper way to play that drunken breathalyzer game that HaD has featured in the past.
Add those sensors to a mobile sentry-bot project: Track down odors and eliminate them!
this would be totally awesome!
LOL yes this would be very awesome!
hey maybe I am stupid but does anyone else after reading this not understand exactly how the sensor works??? If someone could re-explain that for me that would completely awesome I just dont understand how heating the substrate up with a odor or with out a odor gives a different about resistance to a liquid.
hey can anyone re explain how the sensor works?? I might just be an idiot but I dont understand how a liquid substrates resistance changes when there is a odor in the air weather it is heated or not.
The Datasheet pdf can…
http://www.appliedsensor.com/pdfs/APS_MOS_1109.pdf
No adam you’re not stupid I don’t get it either. How do odors cause a change in resistance?
Just read…
http://www.appliedsensor.com/pdfs/APS_MOS_1109.pdf
see it this way,
“bad odour” is a subjective concept, so to have a sensor measure it, you would have to imply that it detects something that causes a defined bad smell, not bad smell itself.
H2S smells like shit, but that doesnt make my GasAlert a shitmeter. The only thing shitty is the number of sensor cells you go through.
@staff Ignore the “Report comment” – i am used to have the “good” stuff on the right side, not on the left as i am from the western hemisphere.
@jeff
The funny thing is, that the sensor detects oxidizing gases, and many of them are non-smelling either :D
NICE job of teardown and part research!
@Spork: It’s quite possible in basic concept. the details of having to Hack things like whatever parameters tune that sensor’s detection curve may be non-trivial. Will it “as is” detect Ethanol or exhaled Ketones Aldehydes? That might need some experimenting:>
while fact checking my memory of the sensors in Hunter’s Blog post, and your query re Ethanol.. I tripped across:
http://www.wellsphere.com/general-medicine-article/exhaled-aldehydes-as-biomarkers-for-lung-cancer/947246
Wohoo- we might Hack a Cancer Detector out of a perfume pot!
Interesting, never knew how many parts there were in one of those things.
Yes the alcohol sensors are broadly similar, they use a pair of heating elements where one is shielded and the other isn’t and a Wheatstone bridge to measure the difference.
how does sensor discriminate air-freshener ?
it specifically senses volatile organic compounds
Which must be the main constituent of the “air freshener” mixture. This could lead to a run away situation: The device detects smelling gases and pumps out more smelling compounds (organic and volatile) to mitigate this situation and detects more smelly compounds….. Until the batteries or the bottle are empty.
turns out if you discharge a large enough capacitor across the sensor, everybody in the room briefly smells the worst fart ever and dies
I’m with Martin D on this, I don’t see how this thing wouldn’t just catch itself in an infinite loop. I know the marketing department wants us to think that the product “eliminates odour” but it obviously just masks odours with stronger laboratory designed “pleasing” odours.
I admit, I’m a bit disappointed to actually see sensors in this thing. I was really hoping it just went off randomly. :)
Fresh air is not full of chemicals (stink bomb)! The fan switch on is a good idea. How about a fart meter where amplitude is measured and displayed. Beans anyone?
I’d wondered how these worked. Hoping to see some great builds using that sensor etc.
OOOh I got one for this. Make them in childrens underwear for when they crap only have it hooked to a pad that zaps em when they do it. Lmao hey if it works for dogs why not kids lmfao……No I am just kidding all in humor folks I neither condone or approve the torture of innocent children or animals.
Actually- you’ve invoked an echo of my “bark trainer” Hack’s sentiment.
Don’t shock the kid- it’s not their fault might be a summary?
My hack on bark collars- Microphone+transmitter on Dog. Receiver and shocker on OWNER. I predict enhanced bark control. We can dream, can’t we?
RE: Sensing of “personal odors” and related.
There’s a tragic reality of some people literally not knowing they’ve got problems like diabetic ketosis for example. And in some cases it’s life threatening if undetected. Most folks with medical conditions have some other warnings but anything that gives forewarning can be a Very Good Thing
.
it looks like those crafty germans beat me to it as far back as june. go google translate!
http://www.mikrocontroller.net/topic/231002
http://automaticgiant.blogspot.com/2011/09/airwick-odor-detect-update.html
It can be used in car to immediately turn off ventilation, when detecting odor or smoke outside.
I think a lot of cars automatically recirculate and purge as necessary, anyway. I remember BMW, Mercedes and Audi offering this for the past twenty years.
:-).
I didn’t know about it. Until now I dealt only with cheap cars. By the way, adding such function to a simple car is a good topic for hackaday.
The link to the blog is dead!?
early in the blogging, i didn’t know how to update posts. so i did an update post and then later i merged them and deleted the update. but instead of deleting the update, i deleted the original. here is a recreation/explanation.
also MODERATOR: if you could update the post so ppl don’t have do dig through comments to find out what happened, that would be great. and if the moderators don’t usually get comment notices, let me know and i will try to contact them.
http://automaticgiant.blogspot.com/2011/10/republish-of-airwick-odor-detect.html
Gone as well…
Joking aside it would be GREAT if it could be adapted as a poo alarm!
We have an autistic son and I’ve spent hours on the internet trying to work out some alarm we could fit in his bedroom to alarm us of this.
He doesn’t wear a nappy during the day but get’s safely wrapped up still in a nappy & all in one PJs at night.
There must also be a use for some parents of babies, or for people litter training puppies/kittens!
IF anyone has any ideas or knows of any alarms coming, would be great to hear.
I am a tech and all the technology in this product is useless.
I was looking forward to the technology doing its job but NO.
No one has mentioned the rfact that the product simply DOESNT WORK.
We have bought several units and placed them at the rear of the shop where we change the babys nappy, to no avail. It doesnt matter how bad the nappy is this product from airwick does not detect or spray when the nappy is changed of after.
I tried it in a small room in which 4 11 year old boys were sleeping and farting all night with the door closed NOTHING not a squirt.
Truly a disapointment from airwick.