Abstract: An apparatus includes a substantially cylindrical housing, a power source, a processor, a communications interface, and an indicator. During operation, a functionalized coin is detected, by the apparatus, as being within a predefined distance of the apparatus. In response to detecting the presence of the functionalized coin within the predefined distance, the apparatus can cause the indicator to exhibit an indication such as vibration and/or light emission. The indicator can include a vibration motor, or a light-emitting diode (LED). The apparatus is sized to fit within a palm of a hand of a human user. The apparatus can also transmit, via the communications interface, a radio frequency beacon signal, and receive, via the communications interface, a reply to the beacon signal and, in turn, transmit a confirmation of receipt of the reply to the beacon signal, to establish a communications connection between the apparatus and the functionalized coin.