| 摘要 |
PURPOSE: A loss preventing system using an RF is provided to immediately inform to a user when losing something even though the user is in any situations. CONSTITUTION: A loss preventing system using an RF is composed of a master and a plurality of slaves. RF modules are respectively are attached to the master and each slave. The master transmits signals to the slaves. When the master receives a feed back in which the slaves are placed within a predetermined range, the master and slaves are not reacted. When the slaves are out of the predetermined range, the master and slaves respectively inform the state using sounds, lights, and vibration. |
