In a tracking device, a crescent-shaped PCB partially encircles a battery to minimize thickness of the device. A speaker and an LED emit alerts upon command of a control apparatus or in response to motion or temperature sensed by sensor. A local network has one hub to tracking devices and a wider area network has multiple hubs for more detailed tracking of devices. A wide area network tracks devices anywhere and stores data of each tracking device including its last known position and its sensor data.