ABSTRACT
One of the recent trends of the design of electronic gadgets is consolidating multiple functions in one small device. This idea leads to adding more controls than ever to even smaller devices. Therefore such interface design is also becoming more complicated. Because of the growing popularity in using cell phones for music listening, the wireless Bluetooth earphones are also demanded to include the music control functions. The challenges of integrating more controls to the designers also bring even greater difficulties in using such devices for the end users. In fact, because of the front-worn design of such devices, most of the interface controlling is not visually guided. This study therefore seeks to investigate the controlling behaviors of such Bluetooth earphone devices, mainly through conducting stereotype survey and observing hand postures under different types of control configuration and device sizes in lab experiments as well.
Data analysis reveals that the gaps between user stereotypes and the real control layouts of the Bluetooth earphones on the market are not significant. Personal preference and device experience do not influence the stereotype of Bluetooth earphone controls. From the results of lab experiments, it finds that, unlike cross-button layout and single-button-joystick layout, significant differences in hand postures were observed with the separated double-button layout for different device sizes and different device orientations (front-hung vs. free-holding style). For free-holding style, hand postures were mostly observed with palm-inward and the device was put in the center of palm. Subjects tended to use thumb, index-finger and middle-finger for such control manipulation. For front-hung style, hand postures with palm-downward and using both thumb and index finger are the majority. 388Regardless device orientations or sizes, on the other hand, most subject participants orient the control device on their fingers with their palms outwards and use their thumbs for controlling both cross-button layout and single-button-joystick layout of Bluetooth earphone sets.
