Example I: Tactile touchscreen for building technology 96

The human-machine-interface of a touchscreen for applications in building technology should provide very simple content and interaction for everybody (including novice and expert users). A touchscreen-based interface is, for instance, used to control a room air conditioning system, in which selecting a digital on/off button switches the system on/off or pressing digital up/down keys changes the temperature in room. When performing these tasks, users are interested in the results of manipulating graphical UI controls for the air conditioning control system, but not in the process leading to those results. They don’t want to be concerned with long-term retention or fully understand the system behind the touch control surfaces. They have little interest in under- standing the technical aspects of controlling the system. The more sophisticated the surface of the touchscreen system, the more complex is the system users have to operate. Tactile feedback provides significant quantities of information through human haptic channel, which helps to en-

sure that users are not confined to simple notifications, and which makes the systems more intui- tive to operate.

Cost-effectiveness, stable operation, energy-efficiency and ease of control will be the key criteria in choosing the most suitable touchscreen technology for building technology devices. An exam- ple of a user interface in this field of application is a tactile panel designed to communicate con- trol actions for an elevator system in an office building. Because it is easy to change the size, style and appearance of graphical UI controls according to use context and screen size, the con- trols can be customized to display several combinations of objects and actions, which would be cumbersome with just physical buttons. As a simple and inexpensive solution, a resistive touch panel without display can be used in this example.

To understand the use of a touchscreen-based device in building automation, consider the fol- lowing scenario:

NKK Int., which has achieved a meteoric rise from a medium-sized travel agency six years ago to a market leader in holiday travel, acquiring an airline and a number of competitor travel agen- cies along the way, has issued an invitation to submit design proposals for a planned luxury re- sort in Bali, Indonesia. Mr. Rogers, who worked with NKK in its infancy six years ago, arrives to present a proposal on behalf of his company Ries-Rolls Design Office, which is treating the project as a major high-profile business opportunity. On Wednesday at 9.45 am, Mr. Rogers ar- rives in a state of anxious anticipation at the New World Building, where NKK has only recently taken over a splendid suite of offices to meet Ms. Lion, NKK's project manager, who made the appointment last Friday with him for 10 am. When he enters the elevator, he is relieved to see that the control panel shows clearly which company is accommodated on which floor. Having thus quickly and easily confirmed the location of NKK Int., he presses the button labeled "5th floor" and "NKK Int", and at the same time perceives a vibration from the control panel, which confirms his selection immediately. Mr. Rogers gives his appearance a final check in the eleva- tor’s mirror. When he leaves the elevator and enters Ms. Lion’s office, the secretary asks him if he had any problem finding the way to NKK Int.’s office. “No problem at all”, replies Mr. Rogers. At 10 am prompt, Mr. Rogers confidently starts to present his company's concept. Fol- lowing a presentation and discussion lasting almost two hours, Ms. Lion expresses great interest in the proposed design, though she tells Mr. Rogers she would like to make a final decision only after she has talked with another two design offices.

Figure 54 shows an example of the interface of the building’s elevator system, which gives an explicit overview of the companies and their locations in the building. The current floor is indi- cated by a red light installed to the left of the interface. The list of companies can be printed on a sheet of paper inserted behind a panel, which makes it easy and cheap to update the interface – if a company moves in or out the building, just take the paper list away and affix a new printed list. This removable interface eliminates mechanical buttons, making it easy to clean the surface and economical to update the content. But an absence of tactile response as confirmation can confuse users as to whether the input has actually triggered an action or not; consequently a common reaction is to press the touch surface repeatedly and hard till a response is received. To achieve

greater energy efficiency, easier handling and quicker setup, a competitively priced touch solu- tion and a dirt-insensitive resistive sensor can be considered for use in this touch panel. Small tactile actuators with, for example, an electric motor can be fixed behind the touch panel to con- vey tactile feedback. When a control indicating the location of one company in the interface is pressed, the system could offer a natural and intuitive effect simulating the pushing of a physical button, instead of just the feeling of pushing on a hard and static surface regardless of where the user presses. With tactile feedback, users recognize immediately that their input has been re- ceived, so that they need less forceful presses and fewer repeated inputs to make certain they have communicated with the touch interface. This reduces cognitive loading and makes selec- tions quicker than with a conventional touchscreen. Meanwhile, tactile effects give users a greater feeling of familiarity in sensing controls and touch events.

Figure 54: Example of a physically removable control surface in an elevator