The use of a wrist-worn sensor that is able to read nearby RFID tags and the wearer's gestures has been suggested frequently as a way to both detect the objects we interact with and to identify the interaction. Making such a prototype feasible for longer-term deployments is far from solved however, as plenty of challenges remain in the hardware, embedded algorithms, and the overall design of such a bracelet-like device. This paper presents several of the challenges that emerged during the development of a functioning prototype that is able to sense interaction data for several days. We focus in particular on RFID tag reading range optimization, efficient data logging methods, meaningful evaluation techniques, and long-term deployments. Author Keywords wrist-worn RFID, gesture detection, wearable interaction ACM Classification Keywords H.5.2 Information Interfaces and Presentation: Miscellaneous General Terms Design, Experimentation