When designing controls and interfaces there are many aspects that can help improve user interaction. The following pages outline some key points for consideration that can make a significant difference.
Types of controls
For the purposes of this publication, the following definitions are used:
Direct controls by which the function is activated without any other operation or feedback required. Examples are an on/off light switch, a four position rotary switch, and a slider volume control.
Indirect controls by which the operation requires some other action such as reading a visual display. For example a rotary control which adjusts the oven timer on the basis that the time changes according to the speed of rotation of the control. Another example would be setting a video recorder using an on-screen display.
Operational sequence refers to control systems which require actions to be done in a specific order. For example if the first press of a knob makes the rotary control one type of function and a second press another type of function. Another example is setting the time and date on a digital clock; it is all too easy to get 'lost' in the process. With such systems it is important that the user knows where they are in the sequence and can easily reset the system to its default (i.e. initial) state.