Mobile robots could be much more useful in homes, if they could locate people, places and objects. Today’s robots usually see the world with cameras and lasers, which have difficulty reliably recognizing things and can miss objects that are hidden in clutter. A complementary way robots can “sense” what is around them is through the use of small ultra-high frequency radio-frequency identification (UHF RFID) tags. Inexpensive self-adhesive tags can be stuck on objects, allowing an RFID-equipped robot to search a room for the correct tag’s signal, even when the object is hidden out of sight. Once the tag is detected, the robot knows the object it’s trying to find isn’t far away.