Controller and key assembly

A controller, comprising:

• a first wall including a plurality of contacts;
• a second wall facing the first wall;
• a keytop pivotally located in a space between the first wall and the second wall and at least partially protruding and exposed through the second wall;
• and
• an elastic member disposed between the keytop and the first wall, the elastic member including conductors at positions facing the plurality of respective contacts, wherein,
• in response to pivoting of the keytop, the elastic member is configured to be pressed by the keytop to electrically connect one of the plurality of contacts to a corresponding conductor of the conductors,
• the keytop includes
• a shaft extending toward the first wall;
• and
• an extension at an end of the shaft, the extension having a maximum width greater than a maximum width of the shaft when viewed in a thickness direction of the first wall,
• the first wall or the second wall includes a restricting portion having an opening with a minimum width greater than the maximum width of the shaft and less than the maximum width of the extension, the restricting portion receiving the shaft in the opening and positioning the extension between the opening and the first wall to regulate pivoting of the keytop.