Scheduling home control devices: design issues and usability evaluation of four touchscreen interfaces

This article describes four different user interfaces supporting scheduling two-state (ON/OFF) devices over time periods ranging from minutes to days. The touchscreen-based user interfaces including a digital 12-h clock, 24-h linear and 24-h dial prototypes are described and compared on a feature by feature basis. A formative usability test with 14 subjects, feedback from more than 30 reviewers, and the flexibility to add functions favour the 24-h linear version.