Pushbutton operated analogue input system responsive to pressure

摘要

A pushbutton operated analogue input key which responds to operator contact pressure comprises a housing (1) containing a fixed diaphragm (2) having a horizontal rectangular slot which limits the total light flux (4) available from an opto-electronic source (3) for transmission to an opto-electronic sensor (7). A spring-regulated pushbutton key (6) carries a slotted moving diaphragm (5) which thereby controls the resultant light transmitted depending on the pressure exerted by the operator and as a consequence of the positive force/displacement characteristic of the spring system.