I would like to know what I would need to do to build a tracking module to monitor home-assigned prisoners. If an RFID tag left my detection range, how could I receive a signal or notification?
We don’t cover devices used to track prisoners within their homes, as they are not really radio frequency identification. Typically, such devices are designed to receive a signal from a tamper-proof device worn around a convict’s ankle. If the device is removed, a signal is sent to the base station and an alert is issued to the monitoring station. The ankle device emits a signal that must be received by the base station. If the person wearing the device goes beyond a certain distance from the base station, an alert is triggered.
To accomplish the same goal with a radio frequency identification system, you would need to use an active tag and set up a base station (perhaps a Wi-Fi router), as well as develop monitoring software that would alert you if an active RFID tag failed to communicate with the base station. It might also be possible to employ Bluetooth Low Energy (BLE) beacons connected to a cell phone. In that case, you would need to develop an app that would alert you if an object with the beacon attached moved out of range. There are some devices like this already on the market.
—Mark Roberti, Founder and Editor, RFID Journal