A Modular Smartphone for Lending

We motivate, design, and prototype a modular smartphone designed to make temporary device lending trustworthy and convenient. The concept is that the phone can be separated into pieces, so a child, friend, or even stranger can begin an access-controlled interaction with one piece, while the own-er retains another piece to continue their tasks and monitor activity. This is grounded in a survey capturing attitudes towards device lending, and an exploratory study probing how people might lend pieces of different kinds of modular smartphones. Design considerations are generated for a hardware form factor and software interface to support different lending scenarios. A functional prototype combining three smartphones into a single modular device is described and used to demonstrate a lending interaction design. A usability test validates the concept using the prototype.