Abstract: A charging device for one or more input modules for a touch-screen device is described. The charging device comprises a charging mechanism and portions which are shaped to receive an input module. The charging mechanism comprises a power input and a power output. The power input is configured to receive power from an external power source and the power input is configured to provide power to one or more input modules which are attached to the charging device.

Abstract: 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.