Manual Activation

There are many different ways to categorize controls. This section uses the means of activation relative to the human user. These categories are: manual, assisted manual, voice activated, sensor activated, and manual control of computers. Each type has benefits and shortcomings that must be considered in interface design. First and foremost, the control must be suited to the user and to the task.

• Manual - Manual controls have been in use at least since the first harp was tuned or the first rudder guided a boat. The term "manual" is derived from the latin "manus" for hand. In controls, however, the term is more broadly used to denote the application of human physical force. Therefore, it includes foot activated controls as well. The manual control to select depends upon the nature of the task.
  • Minimal Manual Effort - The hand is particularly suited for control activation that requires fine, precise movements such as setting a rotary knob, activating a push-button, or flipping a toggle switch. Hand activation can be much faster than foot activation, depending on the design and position of the control. Foot activation is sometimes used when both hands are occupied with the task.
  • Significant Muscular Effort - The hand and arm are used to operate hand-wheels, levers, or cranks when more physical force is needed. For some applications, it may be appropriate to use foot/leg activation of a foot pedal, as leg strength is greater than arm strength in most individuals. Foot activation is not as precise as hand activation and should be used when less precision and greater physical force is needed.

Foot Pedal Control	Hand Crank Controls