Your Windshield Wipers Could Protect Your Car From Theft

With the exception of a house, a car is the most expensive item most people will ever own. A car is also transportable by design. Those two factors make cars a common target for theft. Automakers keep raising the technology bar for their anti-theft systems, but criminals keep finding ways around them. In some cases, the high-tech systems actually make cars easier to steal. So maybe cutting-edge technology isn't the solution. With that in mind, engineers from the University of Michigan developed an anti-theft system called Battery Sleuth that takes advantage of a car's auxiliary features, like the windshield wipers.

This is, essentially, a car immobilizer with a very unusual deactivation protocol. Car immobilizers are electronic devices that prevent current from going to an engine's starter until they've been deactivated. In a vintage car, the key provides all of the security — just like in a house. If someone can turn the ignition, they can start the car. They can also start the car by ripping the wires from the ignition and touching them together (which is "hot wiring"). A modern immobilizer provides an additional level of security by only providing starting power if it receives the proper transponder code.

But there are ways for thieves to subvert modern immobilizers, which is where this new Battery Sleuth technology comes in. Like an immobilizer, Battery Sleuth will not provide power to car's starter until it receives the proper code. The difference here is that the "code" is actually a sequence of voltage changes. When an auxiliary feature in the car, like the windshield wipers or turn signals, activates, it creates a fluctuation in the voltage supplied by the battery. Battery Sleuth monitors those fluctuations to see if they match the "code" sequence. If they do, then it allows the starter to receive the power it needs to turn over the engine.

Because drivers probably don't want to perform a complex sequence of actions every time they start their car, Battery Sleuth provides a keypad to use instead. That keypad creates voltage fluctuations that match the actual sequence of activated auxiliary features. But drivers can also perform the manual sequence if they need to.

The key to Battery Sleuth's efficacy is in the difficulty of spoofing. A transponder code is very easy for ne'er-do-wells to spoof if they know what it should be, but that isn't true of a sequence of voltage fluctuations. That requires actual physical manipulation of the car's electrical system. And because Battery Sleuth doesn't transmit anything via radio, there isn't any easy way for criminals to learn the sequence.

That isn't, however, to say that it would be impossible. If a car thief can gain access to the car's electrical system ahead of time, they could plant a device of their own that monitors and records the sequence just like Battery Sleuth does. They could then replicate that sequence with a device capable of creating similar voltage fluctuations.