The user needs to activate a function or issue a command for a certain amount of time.

Interactive Example

Press the button for at least half a second to see its activated state. Note that you need Adobe Flash.

Context

The user wants to interact with a remotely controlled device, e.g., a door opener. The remote device is activated as long as the user presses the button.

Forces

It may be difficult gather feedback and status information from the remote system. To inform users whether the operation has succeeded or not, visual feedback should be included in the display of the button.

Solution

As long as the user presses and holds this type of button the associated function is active. Upon releasing the button the function returns to its idle, inactive state. To avoid inadvertent activation, an additional debounce state is added: The button responds when pressing and holding it for a certain amount of time, e.g., for 500 ms.

Usability Impact

Error prevention, user satisfaction

Safety Impact

The minimum size and the safety padding guarantee that the button can easily be targeted without inadvertently activating a neighbouring control.

The built in button debounce additionally secures the button against unintentional multiple activation.

Usage

Has been used in European railways voice communication device. One usage scenario of this pattern was a remote door opener, another one was a public announcement system.