While instantly gratifying, buying ice cream from a vending machine isn't quite as much fun as it could be. Which is why SapientNitro and Unilever created the world's first smile-activated ice cream vending machine as part of Unilever's "share happy" campaign.

The technology behind it is sophisticated, but the concept is simple: consumers walk up to the machine, smile and are rewarded with a frozen treat. 

When its motion detectors sense someone is near, the machine beckons them to come closer and interact. Using facial recognition technology, it can then recognize a person's age, gender and emotion, and measure their smile using a "smile-o-meter". If their grin is wide enough, they get free ice cream.

Users can also opt to have a picture of their happy self uploaded to Facebook, which ties in perfectly with Unilever's brand message: "share happy". Currently being showcased at the Cannes Lions International Advertising Festival, the smile-activated ice cream vending machine will be rolled out at high-traffic locations across the globe over the next 18 months.

From security checkpoints that recognize eyes, to cameras that spot friends and family, machines are increasingly capable of smart interaction with humans. Throw in emotion and delight, and you'll create a memorable experience that knocks the socks off traditional advertising.