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I Have Never Thought Of My iPad As A Passenger
June 5, 2014 12:53 PM   Subscribe

My iPad sets off the passenger seat belt alarm on my 2013 Subaru CrossTrek when I put it on the seat. Does anyone know exactly what's going on here and if there is a solution other than disabling the alarm or clicking in the belt when their is no one in the seat?

I called the Subaru dealer and was told that all 2013 and beyond cars had switched to alarm systems that are set off by the human electrical system and electronic devices. He also said he'd heard a rumor that these electrical alarms are federally mandated. I've heard nothing about this and couldn't find any links to the mandate.I didn't check Snopes. As always I am looking for MeFites who can educate me on this and find a way to stop this noisy alarm.
posted by Xurando to Travel & Transportation (19 answers total) 3 users marked this as a favorite
 
Put it on the passenger side floor? Presumably you're not using it while you're driving.
posted by desjardins at 12:56 PM on June 5 [2 favorites]


My 2007 Toyota has this type of alarm, but it takes A LOT of weight to set it off. The only time it's ever happened to me was when I loaded it up with my laptop bag, a bunch of other random crap, and a 12-pack of beer. It was probably the weight of an elementary schooler. My drive home from the store was tedious to say the least.

I'm not sure if Subaru uses a system that is keyed to detecting any electronics on the seat, or has a weight limit of under a pound, but that just sounds really really wrong.

Two things:

Is it only your iPad and nothing else, so less than a pound of weight? Is it possible that you're stacking up the passenger seat with more weight than you think?

Is it possible that there is a problem with the detection system in the seat?
posted by Sara C. at 12:58 PM on June 5


My money is on a faulty weight sensor in the seat. If it's truly just an iPad on the seat, that should not set off the alarm.
posted by spikeleemajortomdickandharryconnickjrmints at 1:00 PM on June 5 [2 favorites]


It does sound like your passenger weight sensors are oversensitive.

If you mostly drive alone, I'd probably ignore the root cause and just stop the alarm with a seat belt key (they look like this one by Chimex). You can also just track down a spare buckle that fits your car (probably for free at a junkyard), or a seat belt extender that does the same thing. You shouldn't HAVE to, of course, but I get impatient about this kind of thing, so it's at least an option.
posted by argonauta at 1:05 PM on June 5


Again, I was told that Subaru and other car makers had
been mandated to move from a weight based system to a system that is set off by the human electrical system and other electronics. I have never heard of such a thing. Has anyone else?
posted by Xurando at 1:10 PM on June 5


I called the Subaru dealer and was told that all 2013 and beyond cars had switched to alarm systems that are set off by the human electrical system and electronic devices.

A little googling seems to indicate it uses an electrostatic capacitance sensor, meaning the weight is irrelevant, as you surmised. This page at a Subaru dealer's website seems to indicate that electronic devices will set it off.

It might be a design flaw, but it's a side effect of the intended effect and there doesn't seem to be an easy answer. For what it's worth, searching for that sensor type and "Subaru" brings up a lot of results with people having similar experiences.
posted by mikeh at 1:11 PM on June 5 [4 favorites]


Can you get some sort of insulating rubber mat to put on the seat?
posted by Rock Steady at 1:12 PM on June 5


I bet this is something a car audio / alarm shop should be able to fix by defeating the pasneger side sensor.
posted by ryanrs at 1:13 PM on June 5


Yikes! That's a little scary: Passengers are advised NOT to sit in the front passenger seat if the seat cushion is wet or if their clothing is wet.
posted by Xurando at 1:13 PM on June 5 [1 favorite]


find a way to stop this noisy alarm

Maybe I don't understand how these fancy new cars work, but can't you just leave that seatbelt buckled?
posted by phunniemee at 1:14 PM on June 5 [3 favorites]


Maybe I don't understand how these fancy new cars work, but can't you just leave that seatbelt buckled?

Being a contrarian who paid a lot of money for the car, I don't want to.
posted by Xurando at 1:16 PM on June 5 [6 favorites]


When water or anything with high moisture content is spilled on the front passenger seat cushion, the airbag is designed to remain OFF until the seat cushion is dry. This will also be the case if the passenger has moisture on their clothing, such as rain-soaked pants or rain gear. In each of these situations, the airbag status may remain OFF even if a passenger is seated.

Well I was totally wrong about the sensor.

"oh hey man, yeah, i'm happy to give you a ride home since it's raining. glad i saw you standing out in the parking lot before i left. hop in. oh shit, you know what, your pants are a little wet from the rain, so, sorry dude, you better not ride with me. the airbags wont' deploy, and seeing as it's raining and all, we're even more likely to get in a fucking wreck now. next time dude."

This is dumb. Maybe there's a workaround on a Subaru forum? My friend loves how programmable the ECU is on his WRX, so maybe that's an option?
posted by spikeleemajortomdickandharryconnickjrmints at 1:24 PM on June 5 [4 favorites]


The seat is lined with electrostatic capacitance sensors - they exist not just to detect the presence of a person, but also their position in the seat. The idea is that the airbags and SRS systems should engage in different ways to different collision profiles and body positions.

Buy a ram mount or some such to hold your ipod.

Sometimes there is an option in the programming software to disable those alarms. I dunno about about subies, but Toyota has software (techstream) that coupled with the appropriate cable will allow them to be disabled. The dealership could possibly help, but may not.
posted by Pogo_Fuzzybutt at 1:26 PM on June 5


You might just get an organizer like this, and flip it around to the front. It'd let you have other small things not fly off when you stop (that'd be a concern for me with the ipad sitting loose), and can easily be flipped around or unbuckled if you have a passenger.
posted by HermitDog at 2:20 PM on June 5


The high frequency signal generator for the capacitive screen on the ipad is interfering with the capacitance sensor in the seat.

If you put like, a piece of cardboard or something under the ipad does it still set the switch off?

If you put a sack of groceries or something on the seat does it set the sensor off?

If it really is just the ipad, then i think i was right on the first count. The last time i played around with these sensors was with a broken iphone 4, some high voltage transformers, an oscilloscope, frequency generator, and a crazy ass friend who wanted to see what would and wouldn't interfere with them, figured out the frequencies they operate at, etc. It's sending out a surprisingly strong signal when it's on, but the signal can be air gapped very easily. Like it only takes a couple inches for it to be essentially undetectable.

Putting your ipad in one of those crappy netbook cases with a ton of overly squishy, mostly useless foam padding would probably do it if the sheet of cardboard doesn't.

Let me know though, i'm REALLY curious about this. I have several other ideas if the cardboard and case don't work, and really want to know if it's any other objects besides an ipad(does an ipad mini do it? a galaxy note? an iphone? how big of a device+signal is it looking for? god i would play with this thing all day)
posted by emptythought at 2:46 PM on June 5 [2 favorites]


Is it possible to turn off the alarm? My wife's Toyota has an alarm similar to this, and after researching on Google it was possible to complete a few steps to turn off the alarm. She opted to leave it on so I never gave it a try. The process was something random like turn on the left blinker and hold down the odometer reset button while turning the car on.

Edit: Found this via Google on some random Subaru forum. A few people said it worked for them. Wear your seat belt.


20 click method:
1.Turn the key to On position, do not start it. (2 clicks forward)

2. Wait till the first set of chimes starts.

3 .Quickly take your drivers side seatbelt buckle and insert and remove into latch exactly 20 times within 30 seconds. Don't rush it, just make sure to fully insert the tab all the way into the latch each time. You should end with the seatbelt unbuckled.

4. After 20 times, turn key to off, and remove key, then try turning back on and starting vehicle. Hopefully this will work for you now.

Sometimes you don't get it on the first few tries.. i am not sure why. Maybe timing? But it will work.

The result is different in that it doesn't do anything dangerous like undermine the airbag system. it simply disables the chime.

Using this method, you should hang on to the directions. If you have to unplug your battery, you will have to re-do it as the seatbelt chime will be re-enabled.

worked first try on my 09
posted by ohjonboy at 2:54 PM on June 5 [2 favorites]


I bet this is something a car audio / alarm shop should be able to fix by defeating the passenger side sensor.

In the United States, it is illegal for a car shop to disable an airbag - disabling the airbag sensors might fall under the same law.
posted by Hatashran at 7:55 PM on June 5


The seat is lined with electrostatic capacitance sensors - they exist not just to detect the presence of a person, but also their position in the seat. The idea is that the airbags and SRS systems should engage in different ways to different collision profiles and body positions.

I was told that my 2013 Ford Mustang has these sensors in the front seats but I frequently put my iPad on the seat with no problems. My huge tote bag will disengage the air bag though, but not the iPad.
posted by tamitang at 9:56 PM on June 5


I have no idea how to fix it, but I just wanted to chime in to say you're not crazy, and I'm glad it's not just me! I have a new Mini Cooper Countryman, and thought for a while the weight sensor on my passenger seat was defective. I soon realized that I could have several bags on that seat, but the alarm only sounded when my iPhone was plugged in and sitting on the seat as well.

Now I just set my phone in the cupholder or on top of something else on the passenger seat.
posted by thejanna at 12:27 PM on June 6


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