Designing Gestural Interfaces

MOVE BODY TO ACTIVATE

WHAT

The physical movement of the body or a part of the body (not just its presence as in Proximity Activates/Deactivates and not a specific gesture) triggers an action.

USE WHEN

Use this when the action you are enabling requires that the person be moving, not just be in an area (as in Proximity Activates/Deactivates). This pattern is often found in alarms and other environmental systems.

WHY

Instead of Proximity Activates/Deactivates, use Move Body to Activate either because the movement itself is meaningful (e.g., an activity such as dancing or running) and the action triggered is related to that motion, or to prevent false triggering.

HOW

This pattern requires the ability to sense movement—frequently, directional movement. This can be accomplished with cameras or infrared beams, or via accelerometers embedded in wearable devices.

EXAMPLES

Figure 4-4. The Nike+iPod Sports Kit consists of an accelerometer that is attached to or embedded in a shoe, which communicates to an iPod Nano. Users can track in real time their calories burned, distance, or time while running. Courtesy Apple.

Figure 4-5. Fukuda's Automatic Door adjusts to the shape of the user as she approaches the door. Courtesy Olga Itenberg.

Figure 4-6. The SensitiveWindow detects the positions and walking directions of passersby to trigger the appropriate content, such as a full-screen movie created to surprise someone walking left to right. Courtesy iO.