Copenhagen's famous Tivoli Gardens opened its gates today for the Summer season and, for the first time, mums and dads do not have to worry about their kids getting lost in one of the world's oldest amusement parks.

Tivoli Gardens has introduced a Bluetooth surveillance system for parents with small children. The Child Spotter Service is based on Bluetooth wristbands developed by Danish company Bluetags and 63 access points manufactured by another Danish outfit, Blip Systems.

Parents can buy a armlet for their child for DKK 20 (about $3). Should a child wander off, they merely have to send a SMS requesting information on the particular tag. Shortly thereafter they receive a message back specifying the location of the child's nearest Bluetooth receiver. The access points can pinpoint the location down to 20 metres.

Bluetags says it is equipping many amusement parks, zoos and shopping centres in Denmark with the location system. One of Denmark’s largest zoological gardens, Aalborg ZOO, was the first to adopt the system. ®