Your Tyres will be Dobbers

David Heath
Monday, 14 April 2008 18:59

Your IT - Home IT

The problem with TPMS is in the implementation.  Specifically in how the pressure sensors communicate with the control unit located close to the driver.

So, if you were designing such a system, how would you communicate the pressure data from the tyres to the central controller, considering you have a design lifetime of at least 7 years and need to keep the costs down?

The designers took a very obvious technology and adapted it to the situation: RFID.  This technology is already in use for short-distance reading of passports, transportation ticketing, retail and many other applications.  In this instance, there is the extra problem of communication distance – the rear wheels of a truck might be 10m or more from the controller. 

One of the side benefits was that innately, RFID uses uniquely serialised chips – no two RFID tags share the same ID number.

Now do you see the problem? 

Allow me to explain.  Firstly, recall two critical pieces of information – “10m communication distance” and “unique serial numbers.”

We all know that passports can be read from a considerable distance to the detriment of the holder.  TPMS is just the same.  Let me summarise a few scenarios that have been outlined by a variety of bloggers. 

Imagine embedding RFID sensors at regular intervals in the road.  Speeders won’t have a chance; neither can they obscure where they’ve been.  Unlike GPS, you can’t simply turn it off.  And obscuring your number plate won’t help either!

What if a “bad guy” knows your TPMS ID numbers?  He suddenly has a much easier time tracking you, or alternately being able to wait for you to go by a particular point.  One blogger even offered the possibility of a road-side bomb being triggered by the victim’s own vehicle.

Are the limited benefits (1/15th litre per day) and a slight reduction in accidents (only if you never check your tyre pressure) worth the privacy trade-off?

As they say, may you live in interesting times.