Unilever's Omo detergent is adding an unusual ingredient to its two-pound detergent box in Brazil: a GPS device that allows its promotions agency Bullet to track shoppers and follow them to their front doors. 

Starting next week, consumers who buy one of the GPS-implanted detergent boxes will be surprised at home, given a pocket video camera as a prize and invited to bring their families to enjoy a day of Unilever-sponsored outdoor fun.

The promotion, called Try Something New With Omo, is in keeping with the brand's international "Dirt is Good" positioning that encourages parents to let their kids have a good time even if they get dirty.

Omo accounts for half of Brazil's detergent sales and is already found in 80% of homes there, so Unilever's goal is more to draw attention to a new stain-fighting version of Omo and get it talked about rather than looking for a big increase in sales.