A module interface of a modular mobile electronic device comprising: • a data interface , coupled to a module communication network of the modular mobile electronic device, that enables data transfer between the module communication network and modules coupled to the data interface, wherein the data interface comprises a first set of conductive contacts, and wherein data transfer between the module communication network and modules coupled to the data interface is enabled by conductive coupling between the first set of contacts and the modules coupled to the data interface; • a power interface , coupled to a module power network of the modular mobile electronic device, that enables power transfer between the module power network and modules coupled to the power interface, wherein the power interface comprises a second set of conductive contacts, and wherein power transfer between the module power network and modules coupled to the power interface is enabled by conductive coupling between the second set of contacts and the modules coupled to the power interface; and • a mechanical interface , coupled to a chassis of the modular mobile electronic device, that enables modules to be removably and mechanically coupled to the modular electronic device, wherein the mechanical interface includes mechanical rails that aid in module retention through friction, and characterized in that the mechanical interface includes an electropermanent magnet, EPM, that aids in module retention, wherein the electropermanent magnet is coupled to the modular mobile electronic device by EPM circuitry of the mechanical interface , the EPM circuitry comprising a voltage booster and a capacitor. • a data interface , coupled to a module communication network of the modular mobile electronic device, that enables data transfer between the module communication network and modules coupled to the data interface, wherein the data interface comprises a first set of conductive contacts, and wherein data transfer between the module communication network and modules coupled to the data interface is enabled by conductive coupling between the first set of contacts and the modules coupled to the data interface; • a power interface , coupled to a module power network of the modular mobile electronic device, that enables power transfer between the module power network and modules coupled to the power interface, wherein the power interface comprises a second set of conductive contacts, and wherein power transfer between the module power network and modules coupled to the power interface is enabled by conductive coupling between the second set of contacts and the modules coupled to the power interface; and • a mechanical interface , coupled to a chassis of the modular mobile electronic device, that enables modules to be removably and mechanically coupled to the modular electronic device, wherein the mechanical interface includes mechanical rails that aid in module retention through friction, and characterized in that the mechanical interface includes an electropermanent magnet, EPM, that aids in module retention, wherein the electropermanent magnet is coupled to the modular mobile electronic device by EPM circuitry of the mechanical interface , the EPM circuitry comprising a voltage booster and a capacitor. <EOS>