An operation state detecting apparatus includes the following. An electronic device includes an operation surface and can detect whether there is contact in a plurality of positions. A sheet material can be attached to and detached from the operation surface. The sheet material includes a projecting portion which deforms to change a contact state on the operation surface according to strength of external force. A processor of the electronic device detects whether there is contact in a plurality of positions in an individual detecting region on the operation surface on which a contact state changes by the projecting portion deforming in a state with the sheet material attached to the operation surface. The processor performs a specific process according to strength or speed of an operation applied to the projecting portion judged based on a detected result of whether contact is detected in the plurality of positions.

An operation state detecting apparatus includes the following. An electronic device includes an operation surface and can detect whether there is contact in a plurality of positions. A sheet material can be attached to and detached from the operation surface. The sheet material includes a projecting portion which deforms to change a contact state on the operation surface according to strength of external force. A processor of the electronic device detects whether there is contact in a plurality of positions in an individual detecting region on the operation surface on which a contact state changes by the projecting portion deforming in a state with the sheet material attached to the operation surface. The processor performs a specific process according to strength or speed of an operation applied to the projecting portion judged based on a detected result of whether contact is detected in the plurality of positions.

A keyboard unit includes: a key; a plurality of members which include the key, and each of which has an engaged section for forming an engaged state, the engaged state changed by turning of the key, at least a portion of the engaged section formed of a conductor; a detector which is configured to detect information on the engaged state of the plurality of members by detecting a conduction state between the at least portions of the engaged sections which are in contact with each other; and a determiner which is configured to determine a musical sound parameter based on a detection result of the detector.

A disclosed pedal includes a base, a movable pedal element actuatable by a user's foot, a spring biasing the movable pedal element to a neutral position, a microcontroller, and a sensor unit, such as an integrated accelerometer/gyroscope dual sensor MEMS device carried by the movable pedal element, configured to send data to the microcontroller indicative of actuation of the movable pedal element, such as by sensing acceleration and angular velocity along three perpendicular axes. The microcontroller can generate an output signal as a function of user input to the movable pedal element and in at least two different modes, selected manually and/or automatically, including a switch mode and a continuous modulation mode. In switch mode the output signal is a discrete trigger, and in continuous modulation mode the output signal is continuously variable over a range.