The touch bezel on the Garmin Forerunner 405 sports watch is a multifunction touch-sensitive control used to
- activate different modes (press & hold)
- navigate through multiple pages in a given mode (tap)
- scroll through on-screen lists (slide along edge)
- make on-screen selections (tap)
- toggle the backlight (press & hold in two spots at once)
To enter a mode, press the bezel on the area labeled with that mode.
In context of use during a workout:
- The touch-sensitive bezel does not respond when wet, but the typical user sweats during exercise.
- difficult to operate while running because
- it relies on visual feedback while the user navigates through nested pages of data by tapping the unreliable bezel
- the bezel requires a press of at least one second to distinguish a mode switch from a select/cycle tap
- Convenience of touch sensitivity is negated because the bezel responds to inadvertent contact and must be locked and unlocked during use, an especially common problem if the user is wearing long sleeves or gloves during a workout.
- Activating different modes
- When GPS is enabled, the satellite location search screen hides the training mode until satellites have been detected or the user explicitly navigates away from the search screen. This search may take several minutes to complete or may never complete if satellites cannot be detected in the area (i.e. indoors).
- Activating GPS mode does not bring up the menu of GPS features. The user must backtrack a step by pressing the quit button after entering GPS mode to bring up the menu.
- Responsive areas change functions depending on feature accessed. A single press might act as a selector, a mode activator, a screen cycler, or nothing (unresponsive).
- The ability to switch modes may be disabled depending on where the user is in the navigation hierarchy, requiring the user to first backtrack through screens. The enabling/disabling of mode switching is not readily apparent to the user, nor is any cue provided to indicate where the user is in the overall navigational hierarchy.
- Navigating through multiple screens in a given mode by tapping the bezel is a nonobvious action because its result does not correspond to the labels printed on the bezel.
- During scrolling, the user’s finger blocks the screen from view
- Making on-screen selections
- To make a selection, the user taps on a section of the bezel that is labeled with an irrelevant function.
- There is no indication if a selection will bring up a nested option. The user must discover the menu hierarchy by trial and error.
- Pressing both buttons locks/unlocks the bezel, but because both buttons are located on the same side of the watch, they can be easily pressed simultaneously by accident while in a bag.
My redesign of the watch includes the following changes to improve the interaction design:
- Make mode access more reliable and less visually demanding by replacing the bezel’s touch-sensitive mode regions with monostable keys that work when wet and are much less likely to respond to incidental contact with clothing.
- Add a discrete sliding switch below the watch face to turn GPS on and off. This makes it easier for the user to set GPS prior to exercising depending on the outdoor/indoor nature of the workout and makes the current state visible at a glance. The switch illuminates in a blinking pattern during the satellite search, so that the user may access training screens before the satellite search completes and knows as soon as the blinking stops that GPS is fully active.
- Add a discrete thumb wheel with grooves to replace the bezel’s scrolling action, so the user’s scrolling finger will not block the screen. Rather than tapping an irrelevant label on the bezel to make an onscreen selection, the user selects by depressing the thumb wheel. Pressing and holding the thumb wheel toggles the backlight. The thumb wheel has less touchable surface area and requires more force to activate than the touch-sensitive bezel, so accidental activation is less likely.
- Move the lap/reset button to the upper left side of the watch so that it is less likely that both buttons will accidently get pressed at the same time when the watch is in storage. Pressing both buttons at the same time unlocks/locks the mode keys and thumb wheel.