Snooping on tire pressure monitors has been demonstrated.[1][2] Range is about 10m with a simple antenna, 40m with a good directional one. Each tire sensor has a permanent 32-bit ID. Tire sensors only emit about once every 60-90 seconds (faster if the tire pressure is low), and only when the vehicle is moving (so the battery isn't drained while the car is parked.) Some can be triggered to transmit by an external LF signal, and this is done at vehicle start-up to get an initial tire check. That mechanism, though, is manufacturer-specific.

As a surveillance system, this has only modest potential. It would be useful to pair this with license plate readers, and notice cars whose license plate/tire ID relationships have changed.

It's probably more useful for taking inventory at car rental lots and finding abandoned/overtime cars in big parking lots. There might be commercial potential in this. Anybody with a big fleet could use something that checks their vehicles as they go in and out.

[1] http://www.winlab.rutgers.edu/~Gruteser/papers/xu_tpms10.pdf [2] http://elib.dlr.de/71397/1/VP_TS_NearctisTPMS_110607.pdf

Honest question to your statement: "It would be useful to pair this with license plate readers, and notice cars whose license plate/tire ID relationships have changed."

How/Why?

Because they generally shouldn't change, unless someone is illegally swapping plates.

I see you have new tires there citizen. Your papers please.

It was poorly worded. TPMS sensors are rarely replaced. I think they have a 10 year/150k mile lifetime.

I have a separate set of Winter wheels which obviously come with their own pressure sensors - so my licence plate/tyre sensor ID pairing will change at least twice a year(I also got a flat once and put a single winter wheel on - what happens then? surely you will get 2 different IDs for one car?).

That's a fair expectation and can be filtered out: you can roughly expect 1 plate to match multiple set of tires. When the same set of tires (or 3 or them) get matched to a different license plate, that can be flagged as suspicious.

New tires won't have been seen on a previous license plate.

Pressure sensors connect to tires to do their job but usually stay with wheels. While not common it's certainly both possible and legal (and sometimes happens) to switch wheels to a different car.

It's fairly common (at least in Europe) for people to have two sets of wheels, on with summer tires and one with winter tires.

Certainly, but keep in mind no one suggested it was either impossible or illegal.

The suggestion above is to merely take note, as it is unusual.

Or legally swapping plates (e.g., personalized plates follow owners to new vehicles, requiring new plates for the vehicle, among other circumstances.)

Or, I suppose, legally swapping wheels, or just pressure sensors.

You don't change plates in the US? Over here(Poland) you get new plates every time the car is sold.

There are also the commercial companies which run vans with cameras everywhere to systematically regularly record license plates/locations; this is then sold to advertisers, hedge funds, skiptracers, PIs etc.

> sensors pickup the bluetooth ID of your tire pressure monitor

AFAIK, TPMS systems are all proprietary and use much simpler protocols than BT.

https://github.com/jboone/tpms

You're not wrong but there are aftermarket direct TPMS that utilize Bluetooth to alert an App on your phone. These aren't very common and it's far more likely that someone is just tracking unique Bluetooth devices and not specifically targeting this very uncommon application of it.

Loosely related...

There are two types if TPMS, direct and indirect.

Direct TMPS use a battery powered sensor on either side of the valve stem to monitor tire pressure and transmit it wirelessly to the car's computer. They're very precise but rely on an expensive battery powered sensor on the valve stem, because of this they are less reliable, prone to failure, damage and tamper. You can identify direct TPMS by the green valve stem caps on a car.

Indirect monitoring leverages the tire speed sensor of the ABS or ESC systems to monitor drag induced by a tire with low pressure, it's not precise but it's accurate and far more reliable. And quite clever IMO.

The NHTSA instituted rule 126 requiring ESC on most vehicles, since TPMS and ABS are subsets of technology necessary for ESC, you should see all three features offered on most new cars today.

umm. green valve stem caps have nothing to do with TPMS. It's used by various places that fill tires with Nitrogen instead of ambient air.

gah... you're right.

Forgive me, both with oredog64, I was told it was the bluetooth tire pressure sensors. I am not familiar with the other systems.

TPM data usually isn't Bluetooth. It's usually an entirely different set of insecure protocols on either 433 or 315mhz.

Whether or not the gov uses these is irrelevant. With your logic, how about I put a camera on your house and snap photos of everybody that goes in an out of the door? Is that OK since the government could already do that if they wanted?

Then what if I take these images and post them online with your name and address? It's all public information and data captured outside of your house. It should then be fine for me to take this public data and sell it to an aggregator, say Facebook and Amazon, right?

Where do you draw the line?

I had never heard of anything like this! Thank you very much for this information.

Luckily for me I drive an old car (definitely pre-bluetooth for sure) so that part wouldn't apply to me, but the increasing use of plate readers applies to everyone, everywhere.

There's an old book you might find interesting called "No Place to Hide" by Robert O'Harrow. If you do read it, try to keep in mind that it was written in 2004, and then consider how much innovation is likely to have taken place since then.

It doesn't matter what you drive.

I cannot tell you where I know this from, but the newest top secret satellites launched recently from Florida will cover the whole US terrain with infrared scanners. Now, given every person has a different size of veins running under their skin in slightly different ways, there are no two people with the same configuration of blood circulation system. So unless you are wearing metal armor 24/7, you are being tracked and cataloged of when and how long you been.

So please - update your tires to let your car know and to notify you when your pressure is low. It might safe your life!

There is a physical limit on the possible resolution. From that alone I call bullshit on your claim. Do you have hard evidence?

You are correct, as the size of infrared waves is much too big to resolve the same level of detail that the smaller waves of visible light can.

But even beyond that, water vapor is opaque to most IR frequencies. So a cloudy day would be enough to render this system useless.

100% bullshit imho.

pc86: would you really bet, or you are just bullshitting me?

We could definitely drive up to Las Vegas and make a bonding, lawful bet. But I need to know how much $ you have on your mind, so I'm not wasting my time here.

I assume "mental check" would be done by physician selected by you. But as long as she/he has expertise in the field and is licensed in the USA, I'm fine with that.

I'm sorry but I don't. But also I cannot prove that NSA is listening on your phone conversations. Or anyone else in that matter.