Re:You don't ever own an electric vehicle
by BenjiWiebe on Monday March 14, 2022 @02:35PM
(#30676226)
Ok, first off - a lot of cars do know which tire is which. Most do it by associating certain TPMS IDs with certain tires. This is what the technician is setting when he does a TPMS re-learn (or reset) after rotating your tires.
Other vehicles actually know which is which without being told. I'm not sure exactly how this is done, but I'm guessing/vaguely recall hearing they do this by using multiple receivers.
As for tracking from a distance - these sensors have very low output power, and a lot of their signal is blocked by the metal wheel. It can somewhat be done but you'll need more than one receiver per block if you want 100% coverage.
Sources: worked as a tire shop technician for a while, messed around with SDR, read a lot online. Also: https://web.wpi.edu/Pubs/E-project/Available/E-project-09111...
Re:You don't ever own an electric vehicle
by chillingeffect on Friday March 11, 2022 @08:42PM
(#30648201)
>gather location data from TPMS sensors.
That's one of the revelations from Snowden files. Us govt does this!
Re:You don't ever own an electric vehicle
by lern_too_spel on Saturday March 12, 2022 @11:59AM
(#30652737)
Source? I heard of this trick from Schneier, but I have not seen any documents saying the US government is using it. In my experience, 90% of the things people say were in Snowden's documents weren't, so I'm skeptical. https://www.schneier.com/blog/archives/2008/04/tracking_vehi...
Re:You don't ever own an electric vehicle
by chillingeffect on Saturday March 12, 2022 @08:19PM
(#30656895)
it's been a while but check back in a few days. if i can find it again i'll post it here.
The transponder in each tire just shouts out its serial number and pressure on 315mhz and then sleeps for a random amount of time. The car counts how many times it has heard the various serial numbers, and assumes the top four most frequently heard serial numbers are its own tires (as opposed to those on the car next to it).
It is sort of stupidly easy to gather location data from TPMS sensors. If I ran a major criminal gang I'd track the cop cars this way. 315mhz is almost VHF, it goes a long way. One receiver per city block should do it. Covering your turf would be easy.