| 摘要 |
A pair of miniature wireless devices can activate an alert to the user of the devices when predefined separation distances between the devices are breached. One device is carried by the owner of an item to be protected, the other device is attached or incorporated in the item, such as a mobile phone, laptop computer, wallet or keys. The devices send signals between each other, with either one-way or two-way communication. The owners device may comprise a wrist watch. A first alert may be triggered on the owners device when a first distance threshold is breached; a second alert may be triggered on the item's device when a second distance threshold is breached. The first threshold may be a weakened signal (fig 2), the second threshold may be a loss of signal (fig 3). |
