Keyboard function in a modular portable electronic device

A method for providing extended user input facilities in a modular device system having first and second portable devices that are magnetically connectable, the method comprising:

• attaching the first portable device to the second portable device using a plurality of magnets and mating magnetically responsive plates to form a first configuration, such that an extended user input surface on a surface of the second portable device is hidden in the first configuration, and providing a first user input facility on an exposed surface of the first portable device;
• and
• detecting that the devices have been reconnected in a second configuration wherein only a subset of the plurality of magnets and mating magnetically responsive plates are mated, such that the extended user input surface of the second portable device is exposed, and allowing user input to the device system via the extended user input surface,
• further comprising using the subset of the magnetic attachment points and the corresponding subset of the magnetically responsive attachment points as electrical conductors when the devices are connected in the second configuration.

A portable electronic device configured to provide extended user input functionality comprising:

• a first user input facility on a first face of the portable electronic device;
• a connector array on an opposite face of the portable electronic device positioned to connect with a matching array on an extension module;
• a set of magnetically responsive attachment elements on the opposite face of the portable electronic device positioned to overlay and mate with a matching set of magnetically responsive attachment elements on the extension module;
• a magnetic sensor on the opposite face of the portable electronic device positioned to overlap a magnet on the extension module when only a subset of the magnetically responsive attachment elements on the portable electronic device overlay and mate with a matching subset of magnetically responsive attachment elements on the extension module;
• further comprising using the subset of the magnetic attachment points and the corresponding subset of the magnetically responsive attachment points as electrical conductors when the devices are connected in the second configuration;
• and
• a processor configured to enable a second input facility located on the extension module when it receives a signal from the magnetic sensor.