Abstract: An operation input apparatus configured to receive a force from an operator, including: a board 10 including a placement surface on which coils 21˜24 are placed, the coils being arranged in a circumferential direction of a circle formed by connecting points apart from a reference point by the same distance; a key 30 that is provided in a side where the force is input with respect to the board 10; and a return spring 51˜54 elastically supporting the key 30, wherein the key 30 includes an opposed surface opposed to the placement surface and an operation surface configured to receive an application of the force, and causes an inductance of at least one of the coils 21˜24 to change with an approach of the opposed surface to the placement surface due to the application of the force on the operation surface.

Abstract: An operation input apparatus configured to receive a force from an operator, including: a board 10 including a placement surface on which coils 21˜24 are placed, the coils being arranged in a circumferential direction of a circle formed by connecting points apart from a reference point by the same distance; a key 30 that is provided in a side where the force is input with respect to the board 10; and a return spring 51˜54 elastically supporting the key 30, wherein the key 30 includes an opposed surface opposed to the placement surface and an operation surface configured to receive an application of the force, and causes an inductance of at least one of the coils 21˜24 to change with an approach of the opposed surface to the placement surface due to the application of the force on the operation surface.

Abstract: An interface apparatus is provided that can reproduce compressed audio data stored in a storage unit without activating an external computer connected to the interface apparatus. The interface apparatus includes the storage unit, a communication unit that exchanges data with the computer, an audio reproduction unit that reproduces the audio data retrieved from the storage unit, and a control unit that controls both the communication unit and the audio reproduction unit. Regarding reproduction of compressed audio data, the interface apparatus does not require another control unit dedicated for the reproduction. Accordingly, the area of circuit board required for mounting components can be reduced and the pattern of the circuit board can be simplified.