You're being watched - by a rock

The stones will cry out! It’s a nice phrase with a Biblical ring, understandably so as it occurs in both Old and New Testaments.
Written by Rupert Goodwins, Contributor

The stones will cry out! It’s a nice phrase with a Biblical ring, understandably so as it occurs in both Old and New Testaments. Now it’s coming true in the visibly Biblical landscape of Afghanistan, as Lockheed Martin is promoting smart rocks that lie quietly for weeks until the time comes to relay intelligence about their environment.

The idea, the manufacturers and military customers explain, is that a network of sensors hidden in fake rocks can silently monitor the ground for evidence of passing vehicles, animals or people, and squirt any results over mesh networks until they reach a satellite uplink. Thousands of miles away, intelligence services can build up maps of activity over many months without needing any human operatives in the area.

Because the electronics are low power enough to be run from embedded solar cells charging tiny batteries, they have a very long — potentially indefinite — life. They’re cheap as chips, or at least as cheap as mobile phones. And they look like rocks. With only a handful of small, very short bursts of radio transmissions over a very long time, they’re practically undetectable and effectively unlocatable. Or so their fans claim.

There are just a couple of quibbles. The first is that if you make a radio transmission very very short and very very occasional — it’s still very, very locatable. The idea that you need a long signal to home in on may have been true in the 1930s, but not subsequently: techniques developed to pinpoint submarines sending burst transmissions mean that if you’ve got a few receivers dotted around the place listening all the time, you can find a transmitter the moment you hear it. (A note to UK readers: a nationwide network of 24/7 radio monitors is watching our airwaves with just this in mind.Probably. Although it ran a very positive proof of concept in 2006, recommending one be built, Ofcom hasn’t replied when I’ve asked about it.) And the same technology that makes it possible to build the rocks cheaply and in large numbers works just as well for the detectors.

The other quibble is — if the security services are prepared to deploy sneaky pebbles in far-away war zones to catch potential terrorists, they’ll be equally happy to do so closer to home. We are all potential terrorists. as anyone who flies will testify, and even the makers say that the smart rocks will be useful ‘even around corporate headquarters’. Which means that there’ll be bunches of open-source hardware hackers who’ll be only too happy to lash together some Arduino-based breadboards that’ll do the location work, just because they don’t fancy being spied on.

That'll encourage people to go rock-hunting. You can consider it geocaching with a very nice collection of free electronics to tinker with once you find it: something that, in a country with very few Maplins stores. even an Afghan tribesman with a technical bent would find attractive,Perhaps that's not such a bad thing.

These stones may talk, but they'll also give themselves away.

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