Special printable metal tags, developed by engineers at UC San Diego, are able to turn everyday objects into "smart" Internet of Things devices. The tags are made from copper foil printed onto paper-like substrates that are designed to reflect radio signals from a WiFi router. When someone touches the tag, the signal is disrupted and that disruption is picked up by a WiFi receiver, such as a person's smartphone. The tags can attach to everyday objects such as water bottles, books, and doors to turn them into "smart" devices that signal whenever the object moves. Learn more about the printable metal tags at UC San Diego.