Patent attributes
A removable input module for a touch-screen device is described. The input module comprises an attachment mechanism to attach the module to the touch-screen device, one or more input controls and an accelerometer and/or magnetometer. The accelerometer and/or magnetometer are configured to provide signals to be used to determine the orientation of the input module relative to the touch-screen device and/or to another input module which is attached to the same touch-screen device. In an embodiment, the input module comprises a processor arranged to analyze the output of the accelerometer and/or magnetometer and determine the orientation of the input module.