Abstract: A pressure sensitive electronic device has a display, a case, a processor, and a pressure sensor, such as one or more force sensitive resistors. When the pressure sensor detects pressure on the case, the information displayed on the display is changed. Pressure in one or more dimensions (X, Y, and/or Z) on the case is detected by the pressure sensor. Most commonly, the information that is changed on the display is the repositioning of a cursor on the display, although switching between various operating modes and/or writing on the device can also be performed. The cursor is repositioned corresponding to the direction and magnitude of the pressure detected on the case. Pressure can also be used to execute an operation corresponding to the position of the cursor on the display. Keys or other input devices (mouse, trackball, etc) are not required to control the movement of the cursor on the display, execute operations, or switch between various operating modes of the device.

Abstract: The method comprises displaying menu labels (28) on a display screen (30) in proximity to an adjacent row (34) of keys of a keyboard (22), defining keys within the row (34) to match the menu labels (28), and displaying an annunciator (42) on the display screen (30) between each menu label displayed and matched key to indicate the matching of the label with key. To further assist the user in selecting the desired key, keys within the row (34) that are not matched are disabled and an error annunciator (44) appears if an unmatched key is pressed. Alternatively, unmatched keys may be allowed to execute functions not related to the displayed menu labels. The apparatus for accomplishing the method is included within a calculator (20) and comprise a programmed microprocessor (14), a top row (34) of keys for executing the labeled functions, and an LCD display screen (30) for displaying the menu labels (28) and annunciators (42, 44).

Abstract: A user-to-calculating device interface for the solution of mathematical equations. The interface allows for the simple construction of equations which may be utilized or stored. Once an equation has been constructed, it may be solved. The preferred embodiment shows a device wherein equations may be solved utilizing an interface which utilizes a minimum number of key strokes. The user interface includes a top-row-keys interface, in which each menu key within a plurality of menu key are used to both store and to calculate a variable. If two labeled menu keys are pressed in succession, the machine calculates a result for the second. Otherwise, pressing a labeled menu key performs an assignment ("=") operation and then stores a number and displays the number in a display line as a variable represented by the menu key pressed. Pressing an unlabeled menu key does nothing.