Active tags require batteries because the signals they send can be received from 100 feet to miles away, depending on the strength of the tag and the problem being solved. With the active tag, the tray can indicate its position at any time. Hilton explained that, or placing a trash can in the production area, when it reaches a certain weight, it will send a signal that it needs to replenish energy.
Although passive tags do not signal, they are useful for other applications and do not require their own power supply. Instead, the reader will receive the tag as it approaches. For example, attaching a passive tag to a car on a production line can not only indicate what a particular car is, but also indicate what the station’s staff needs to do for a particular car. Passive tags, depending on their application, can be as cheap as 7-10 cents, so they can be shipped with the product and never come back.