Thursday, April 10, 2008

Where Are You? Your TPMS Knows. And Tattles!

Driving someplace? Won't take much to find out where (and when, and how fast you were driving there) in the near future.

Your tires will be tattling, through your Tire Pressure Monitoring System (TPMS) which is a required installation on all US autos beginning 2007.

In a typical TPMS, each wheel of the vehicle contains a device (TPMS sensor) - usually attached to the inflation valve - that measures air pressure and, optionally, temperature, vehicle state (moving or not), and the health of the sensor's battery. Each sensor transmits this information (either periodically or upon request) to the on-board computer in the vehicle. To differentiate between its own wheels and wheels of the vehicle in the next lane, each TPMS sensor contains a unique id. The receiver is "paired" to the sensors very much as a Bluetooth device.

...TPMS cannot be turned off. It comes with a built-in battery that lasts 7 to 10 years, and the battery-less TPMS sensors are ready to hit the market in 2010. It does not matter how long you own the vehicle – transportation authorities keep up-to-date information about vehicle ownership

...With minor limitations, TPMS can be used for the very purpose of tracking your vehicle in real time with no substantial investments! TPMS can also be used to measure the speed of your vehicle. Similarly to highway/freeway speed sensors that measure traffic speed, TPMS readers can be installed in pairs to measure how quick your vehicle goes over a predefined distance. Technically, it is even plausible to use existing speed sensors to read TPMS data!

By the way, if you have OnStar:

Yes, many vehicles already come with advanced tracking technologies, like OnStar, but they usually offered as options, so if you do not appreciate the possibility for OnStar support people to eavesdrop on the conversations in your vehicle (yes, they can do that), you can say "no, thank you" to the dealer, or, as the last resort, disable the evil device by cutting its power supply

Aldous Huxley, call your office.

HT: Schneier

1 comment:

Disgruntled Car Salesman said...

You CAN take TPMS sensors out of your wheels. The car will think your tires are flat all the time and the indicator light will stay on, but performance will not be affected.