republish of airwick odor detect teardown

So I accidentally deleted this post but for some reason it appeared in Reader so here is a lucky recreation: I’ve been meaning to post this for about a week now. My wife got a whole bunch of these Airwick Odor Detect things for free with her coupon voodoo. So naturally, I was compelled to take apart at least one. Here’s what I found:Inside the case, which was interestingly fastened with melted snap-tabs instead of screws or regular snaps (you’ll see if you open one, just use a knife to go in through the side and cut through them), was a built-in holder for the three included white-label AA batteries.
Also the ARNIE COMPACT3 ISS.4 controller board

the wired-in ARNIE SENSOR Rev0

board and a momentary SPST switch like the power button on lots of computers. Also, a solenoid with a built-in nozzle

was the only thing that used a connector (a JST, like LiPo’s) to connect to the controller board.So the really interesting bit was the ARNIE SENSOR Rev0 board. I did a little digging to see if anyone else had figured out what the deal was with that part. I had expected a typical gas sensor such as a http://www.sparkfun.com/products/9404 but since I didn’t know how they worked until a moment ago, I didn’t realize that I'm pretty sure they work the same way but just look radically different. I didn’t find anything documented about a teardown (didn’t look terribly long, feel free to update me on a previous posting) but I did stumble upon this: http://www.prweb.com/releases/2011/03/prweb5115684.htm which put me on the right track. Allied sensor makes some parts and this seems to be the mystery part on the board: http://www.appliedsensor.com/pdfs/APS_MOS_1109.pdf
A related sheet has this interesting note: Do not operate gas sensors in the vicinity of silicone and polysiloxanes. I’m guessing it has something to do with this document: http://www.cdc.gov/niosh/mining/pubs/pdfs/svpoc.pdf, apparently they can poison catalytic methane sensors which I feel confident now are similar. So yeah, the meat of this system is this nifty little sensor chip which has 4 leads. Two power a heater and two give you a resistance based on the chemical activity on the chip and you measure this to get air quality. Cool huh?

it looks like those crafty germans beat me to it as far back as june.  go google translate!

1 comment:

  1. I'm currently reverse engineering this exact product and I hit the jackpot with this page. Thanks so much for posting!