Ubiquitous ivy is a small ivy-like tag to receive and transmit a signal. The user can create a pair of tages by combining sensors and actuators and share the tags with other users. The tags send a simple signal to each other according to the use of the object, which the tag is attached. By using the signals emitted from these tags, the users are able to communicate through using their objects ordinarily, without any specific operation.
Reference: Shibata, I., Okude, N. 2005. Ubiquitous ivy: A Communication Media for Intimate Company. In Proceeding of SIGGRAPH '05
