A sensor is any device, such as a thermometer, that detects a physical condition in the world. Actuators are devices, such as valves and switches, that perform actions such as turning things on or off or making adjustments in an operational system. Companies can integrate sensors and actuators to create a closed-loop operational system between remote locations such as retail stores, distribution centers, or manufacturing sites and the enterprise applications used to run the business.
One form of sensor technology is radio frequency identification (RFID), a method of identifying distinct items using radio waves. RFID is based on tags that contain microscopic chips used to store information about the item to which it is attached. The tag also contains a small, flat antenna. If the tag contains a power source, it is an active tag. If it depends on the reader for power, then it is a passive tag.
A passive tag read is activated by the radio waves emitted by a tag reader. When the antenna in the RFID tag encounters these radio waves, it forms a magnetic field that allows the tag to draw power and send information back to the reader. An active tag read occurs when the RFID tag has its own power source for the antenna and emits a signal that can be tracked.
For more information on the possible business solutions with this technology, refer to IBM® Sensors and actuators.