Think of them as billboards 2.0. Where traditional hoardings – flapping paper promoting outdated products – once stood, digital adverts are now watching you watching them. Think you can ignore them? Think again. The latest ads use smells and 3-D visuals to catch your attention, even beaming sound messages to cut through the clamour of a busy street.

Whereas advertisers were once happy simply to place posters for doughnuts near police stations, they now insist on knowing who is viewing their adverts. Companies such as Quividi, a French marketing technology firm, are happy to oblige.

Quividi installs camera systems in billboards and a computer analyses passers-by. “We know this many people have walked in front of the screen, how many turned to face the ad, and how long they looked at it,” says Paolo Prandoni, Quividi’s chief scientific officer. “We can even tell their gender with an accuracy of 85% and measure who approaches to find out more.”

Quividi has digital adverts that change depending on whether a man or woman is watching and is working on upgrading its system to detect different ages and even family groups. The company insists no data are permanently recorded.

One customer of Quividi is Motomedia, a Glasgow advertising agency that specialises in interactive shop windows. A campaign for the ITV show Pushing Daisies used sound, video and even a vent pumping out the smell of freshly cut grass, all controlled by Quividi’s technology.

Kenny Maclean, Motomedia’s founder, says: “This is a society where all businesses measure the performance of consumers. Audience measurement showed that our original static advert wasn’t effective, so we put the video on a four-minute loop.”

Holosonic, a US technology company, is taking the idea one step further. It has developed the Audio Spotlight, a system that fires a beam of sound onto a small area from a distance of more than 60ft. The effect, the company claims, is to “startle and entertain” pedestrians without being audible to anyone outside the zone.

If that wasn’t intrusive enough, three Xscape ski centres are the first UK locations to use 3-D ads with images that “jump out” 2ft from the screen.

Can we expect 3-D soap packets and jingles beamed into our heads as we commute to work? Roadside billboards require planning permission that can be refused on the grounds of road safety or local amenity – hurdles that video screens and sound beams are unlikely to clear. High street shopping is another matter. A legal loophole means even noisy, smelly shop windows don’t require planning permission, just a local authority advertising permit.

One scrap of comfort comes from Bill Wilson of the Outdoor Advertising Association. “We did see talking posters in the past,” he says, “and the number of complaints was incredible.”

TRAVELLER’S FRIEND

Live Luggage PA £700 www.liveluggage.com08458 696 171

The world’s first power-assisted suitcase promises to make your baggage feel 85% lighter. An angled handle redistributes weight over a pair of wheels powered by electric motors. To save power, the motors kick in only when tilt switches sense you’re struggling uphill or over rough ground, and will recharge the battery on a downward slope. Don’t worry about your togs speeding off without you: a sensor in the handle kills the motors should you let go. The 12V NiMH battery pack charges up overnight (international adaptors are provided), and should last for two-and-a-half hours. The technology accounts for less than a third of the 24lb total weight of the hard-shell design, and it can carry up to 70lb of baggage. Designed in Britain, too.

COOL FOR KITTS

Mio Knight Rider sat nav Price tbc www.mio.com

We’re still waiting for parachutes and grappling hooks to be built into the average car, but at least one technology showcased in Knight Rider’s Kitt is about to become reality: actor William Daniels will soon be telling you to take the second right. If your name is one of the 300 programmed into Mio’s Knight Rider sat nav, the man behind the voice of Kitt will ask you where you want to go as LEDs pulsate in synch. It’s based on Mio’s 300 series, so you get a 4.3in screen, speed camera data and European maps.

SMART SPEAKERS

Klipsch RoomGroove £199 per unit www.klipsch.com

These iPod speakers can be combined to form a wireless, multi-room music system. Each unit contains a retractable, recharging iPod dock, plus an auxiliary input to connect to a hi-fi or other make of MP3 player. Dot additional RoomGrooves around the house and they’ll wirelessly connect, streaming music to any or all units within 75ft. Sound quality should be good – Klipsch won our last iPod dock group test.

gear@sunday-times.co.uk

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