Application design for a smart watch with a high resolution display
`
`Chandra Narayanaswami, M. T. Raghunath
`
`Wearable Computing Platforms
`IBM Tl Watson Research Center
`Yorktown Heights, NY 10598
`{ chandras, mtr}@us.ibm.com
`
`Abstract
`
`technology have made it possible to
`Advances in
`package a reasonably powerful processor and memory
`subsystem coupled with an ultra high-resolution display
`and wireless communication into a wrist watch. This
`introduces a set of challenges in the nature of input
`devices, navigation, applications, power management, and
`other areas. This paper describes a platform we have
`developed and the decisions we have made about how to
`address these challenges.
`
`1 Introduction
`
`a
`A wrist watch is an attractive form factor for
`wearable computer. It has the advantage of always being
`with you; and it can be instantly viewed with the flick of
`the wrist. By comparison, devices such as pagers, cell
`phones, and PDAs are typically worn on belts or kept in
`pockets and need to be picked up and opened first before
`they can be accessed. One of the reasons for the success of
`the Palm was its moving to an instant-on paradigm.
`Wristwatches move us
`to
`the next step;
`to
`an
`instantly-viewable paradigm.
`Because people generally keep watches on their wrists,
`watches are less likely to be misplaced compared to
`phones and pagers. For example a hip holster is not the
`best place to keep a cellular phone while sitting in a car
`and so people tend to keep them in the car seat and forget
`them when they leave the car in the parking lot.
`The watch form factor requires a relatively small screen
`size, and there is not much room for input devices or
`batteries. The value of a wristwatch platform depends on
`finding good solutions to these issues. To interact with the
`watch, we need both hands since the hand on which the
`watch is worn is practically useless for controlling input
`devices on the watch.
`
`Several smart watches are available commercially
`today.
`Personal
`Information Management
`(PIM)
`applications are provided on the Seiko Ruputer™ [I], the
`onHand PC™ [2], the Casio PC-Unite™ [5] and the Timex
`DataLink™ [4]. These watches pack an impressive amount
`of function but have low resolution displays. This limits
`the amount and type of data that can be displayed on their
`screens. Some of the above have cuinbersome/confusing
`user interfaces with many buttons leading to limited
`adoption. For example, on the Seiko Ruputer™ it is quite
`difficult to get back to the clock face from any application.
`The Casio WMP-IV™ [5] is a wearable MP3 player, the
`Casio WQV-1™ [5] is a wearable digital camera, with a
`120xl20 display, the Casio BP 100™ measures blood
`pressure and the Casio Satellite Navi™ [6] provides GPS
`on a watch. The Timex Beepwear™ watch has a built in
`pager. The Swatch Access™ watch [IO] has an RF id tag
`ski pass at some ski resorts.
`which can be used as a
`Swatch is also working on a cell phone in a watch called
`Swatch Talk™. The NTT PHS Personal Handy Phone
`System [7] and the Samsung Watchphone Anycall™ [7]
`are watches with a telephone. Polar produces heart rate
`monitor watches (Smart Edge™, Beat™, Protrainer NV™,
`Lady Beat™ Target™, Pacer™).
`There is plenty of interest in adding function to watches
`in the industry. Our interest is not in so much in providing
`a watch, as in providing an open, extensible computing
`platform in a small form factor. Our objective is to
`understand the challenges in packaging, hardware design,
`power management, and embedded software.
`
`2 Wrist watch computer overview
`
`The wrist watch computer is a wearable personal
`information access and alert notification device with both
`short range and long range RF wireless connectivity. The
`initial display for the watch is a 96xl20 pixel monochrome
`LCD display. Subsequently, the display will be enhanced
`to an ultra high resolution (600 dpi) monochrome display.
`The applications and user interfaces described in this
`
`0-769S-079S-6/00 $10.00 © 2000 IEEE
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`paper are targeted to the higher resolution display and
`were prototyped on a commercially available backlit VGA
`resolution display.
`These display and communication capabilities could
`make the wrist watch computer the preferred viewer for
`other devices that are around you and for your electronic
`agents running on web, business or e-commerce servers
`
`Figure 1: Enhanced Shell and Basic Shell
`
`on the intranet or the internet.
`At the core for the wrist watch computer is an ARM 7
`based low-power system board that runs Linux. The
`system board uses state of the art technology such as
`
`Figure 2: Main card and communication cards
`
`Surface Laminar Circuit™ (SLC). It is 34.7x27.5x3.0mm
`in size. Additional communication cards are used
`to
`support short range wireless protocols such as Bluetooth.
`Power is supplied
`by a rechargeable lithium-polymer
`battery.
`Figures 1 . and 2 show initial wrist watch computer
`prototypes.
`The watch must be viewed as a companion to some
`other key devices such as a PC in an office, a cell phone
`in a bag, or a wireless beacon in a building. So the watch
`need not do all the functions a user wants but must
`
`8
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`communicate and cooperate with other devices so that the
`strengths of each device can be exploited to the maximum.
`
`3 Selection of input devices
`
`The choice of input mechanisms is critical for ease of
`use.
`In our effort to find the right input devices for the
`wrist watch computer, we first studied the advantages and
`disadvantages of input devices on a set of commercially
`available products including the Palm PilotTM, Psion Series
`5™, HP JornadaTM and other handheld PDAs, the RexPro
`5-DS™, RIM Interactive Pager 960TM, Hertz NeverLosfM
`car navigation system, several digital cameras, remote
`controls, smart watches, and cell phones. The pros and
`cons of several choices
`for input devices are described
`below:
`Keyboards: Though useful for entering large amounts
`of text, watches do not have the surface area and volume
`needed for hardware switches such as keyboards. Even if
`we were able to fit a tiny keypad with a limited number of
`keys on the wristwatch, it would be difficult to use for
`most people.
`Touch Screen: A touch sensitive screen can be used on
`the wrist watch computer to provide for soft switches and
`character input. The relative sizes of a watch face and a
`human finger limit the number of distinguishable touch
`zones to four or five, although a stylus could be used on
`the watch face to accept fine grained input such as graffiti.
`It was clear to us through experimentation with the Casio
`VDU 200BTM watch that touch screens frequently showed
`screens other than the desired time screen due to accidental
`activation every now and then. Despite this shortcoming
`we felt
`that a touch screen would be a good
`input
`mechanism to support on a wrist watch since it was more
`versatile and more elegant compared to buttons. And for
`usabilitiy reasons, we limit the number of distinguishable
`zones to the four - one for each corner.
`Scrolling: A touch screen provides a good selection
`mechanism but does not perform too well as a scrolling
`mechanism. For this purpose we considered a rocker
`switch, a rotating bezel, and a roller switch. The rocker
`switch rocks up or down. It can be pushed in to select.
`The roller wheel and the bezel allow complete revolutions
`to scroll up or down. The roller wheel may be pushed
`towards the center to select and the bezel may be pressed
`down to select.
`Initial user tests revealed that a rocker
`switch (fitted on a RexPro 5-DSTM) was superior to touch
`screen actions, but a roller or bezel that allowed complete
`rotations seemed easier to use and more natural. Since our
`present watch is rectangular, we chose a roller wheel over
`the rotating bezel.
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`We positioned the roller wheel to minimize the chance
`of accidental activation by bending the wrist. The user has
`to push in the southwest direction to select.
`As shown in Figure 1, the wheel is also positioned in
`the northeast corner to accommodate both left and right
`handed users. Right handed users anchor their thumb to
`the bottom left corner of the watch and use their index
`finger to roll the wheel, moving the index finger north to
`south or vice versa depending on the desired direction of
`rotation. Left handed users who wear the watch on their
`right wrist tend to anchor their thumb in a similar fashion,
`but move their index finger along the upper boundary of
`the watch, in an east-west or west-east direction. Therefore
`placing the wheel at the northeast corner of the watch was
`desirable.
`Alternatively, for left-handed users we could build a
`mirror-image watch, where the watch could be reversed so
`that the roller wheel appears in the northwest corner
`instead of the northeast corner. However, in this case there
`would be two distinct types of watches: left-handed and
`right-handed ones.
`External 1/0: External input/output devices can interact
`with the watch over wireless standards such as IrDA and
`Bluetooth. For example, one could bring the watch near a
`Bluetooth connected keyboard, perhaps a Twiddler™, to
`enter information into the watch.
`Voice recognition: The wrist watch computer includes a
`microphone and speaker, so that speech based interfaces
`are possible. We have found that current technology limits
`extensive use of this concept, although the capability can
`be improved using a wireless connection to an adjunct
`device with more computing power that can be used for
`doing part of the voice recognition.
`
`4 Application and interaction design
`
`The primary applications of a watch are related to time.
`Watches started with the ability to tell time. Then alarms
`were added to help people wake up. The next generation
`of smart watches will extend this concept by allowing
`people manage their time, provide personal information
`management (PIM) functions and also save time in their
`jobs by receiving just in time information on their wrists
`by leveraging short range wireless connectivity.
`Before designing the applications for the watch, we
`spent a great deal of time trying to simplify the user
`interface by taking advantage of the high resolution
`display and the chosen input devices.
`We started a study of existing devices which suggested
`we focus on navigation between functions. After some
`the following requirements for
`study, we settled on
`navigation between screens on the watch:
`
`i. a quick return to the watch face from any application,
`ii. a time-out to the watch face from any function,
`iii. one touch deactivation of alarms,
`iv. direct access to the main list of applications,
`v. user programmable touch screen areas that could be
`used to access the user's most important applications,
`vi. user ability to perform most of the common actions
`without lifting finger off the wheel,
`vii. the ability to easily return to the previous screen.
`(Our studies
`indicated
`that people had become
`familiar with the browser model and the concepts of
`following hyperlinks and going back in the browser
`history stack. Therefore extending the concept of a
`browser back button to every watch face screen was
`desirable.).
`We wanted the usage of the wrist watch computer to be
`obvious and avoid the need for a thick user manual for the
`watch. We started with human computer interaction (HCI)
`concepts from familiar computing environments such as
`web browsers, etc., and then employed a user-centered
`design process to tune the environment.
`From our user study, we determined users were
`typically not aware that the screen was touch sensitive or
`that the roller could be pushed in to generate a selection.
`So some documentation to make the users aware of these
`features was useful.
`With the basic input mechanisms on the wrist watch
`computer, and the four zone limitation we have placed on
`the touch screen, the following input options are available
`on the watch.
`i. Press any of the four regions on the touch screen
`ii. Roll the roller wheel clockwise
`iii. Roll the roller wheel counterclockwise
`iv. Push the roller wheel in the SW direction to select
`In order to facilitate a quick return to the watch face,
`we decided to dedicate a touch on the top left corner to go
`back to watch face, irrespective of what the watch face is
`currently displaying. There is one exception to this rule
`however; if the watch face is already displaying the time a
`top-left tap takes the watch to the main-menu screen.
`The top-left zone was chosen for this return-to-home
`function, since a right-handed user's right index finger
`(who wears his watch on the left hand) will almost
`completely cover the wrist watch computer display when
`this zone is being pressed. Obscuring the screen in this
`fashion is not desirable if the user needs to remember some
`information on the current screen. However, since a
`top-left tap results in a complete switch to a well-known
`screen the user is least concerned with the current contents
`of the display being obscured in this fashion.
`In order to support a consistent page-back mechanism
`we decided to dedicate the bottom left zone to the go-back
`function - in this case 75% of the screen is visible for the
`right-handed user.
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`The two right zones are under the control of the
`application that currently has control of the screen. The
`application may decide to use them to go to the next page
`or previous page, or to invoke a list of menus for a
`hyperlink or an application, or for other purposes.
`For left handed users the conventions of functions
`mapped to the left and right zones may be reversed in
`software. This is another advantage that results from the
`use of a touch screen.
`The above conventions are suspended when an alarm
`sounds.
`In this case the alarm is quickly silenced by
`pressing any zone on the watch display.
`By asking people we determined that many found it
`easier to set time on an analog watch using the watch stem
`than it was to set time on digital clocks with buttons.
`Since this design is for a high resolution display where the
`hands of the watch could be displayed in an analog fashion
`we use a circular metaphor and analog representations in
`our screens whenever desirable. The circular metaphor on
`the screen works well with the roller wheel.
`Rolling the wheel also causes a scrolling action when
`textual content is displayed on the screen. Clicking the
`wheel causes a selection action similar to a mouse click.
`For instance in the case of setting time, rolling the wheel
`moves the hands and clicking the wheel sets the time to the
`current time displayed by the hands.
`The availability of the back button provides a quick
`way to
`undo tasks or revert to previously computed
`screens and is very convenient and saves time in many
`instances. For example we found that some users were
`looking for a person's phone number and then would
`quickly want to check what time it was at the person's
`location and would go back to the clock, and in the
`meanwhile forget the phone number they just looked up.
`We solve situations like this by allowing the user to jump
`to the watch face with one touch and then get back to the
`previous screen with another touch.
`The history stack maintained for the back button
`functionality does not preserve every screen; only a few
`canonical screens are preserved for any application. So for
`example it would be quite useless to preserve every screen
`update that was made during a stopwatch application that
`counted milli seconds.
`We found that touch screens on watches are also
`activated accidentally by people trying to keep their watch
`screens clean. To address this, we use a variable time-out
`mechanism that returns the watch to the time screen from
`any screen after a time-out interval. Furthermore, the
`time-out period is initially set to a small value and
`increased gradually till it reaches an upper limit if the user
`is actively using the applications. For instance the time-out
`interval starts at 10 seconds. After the first interaction with
`the watch (tap on screen/activation of wheel) the watch
`will time out to the clock face in 10 seconds if there is no
`
`further interaction. If there is a second interaction within
`the 10 seconds the time-out is increased to 20 seconds and
`so on till it reaches say one minute. If at any point the
`watch times out to the clock face, the time-out interval is
`reset
`to 10 seconds. This mechanism ensures
`that
`accidental activations quickly revert the watch to the clock
`without annoying the user with spurious time-outs when
`the watch is being used actively.
`
`5 Data Model
`
`Since the wrist watch computer does not have a
`keyboard, textual content will most likely be created on
`other devices, such as PCs, and transferred to the watch.
`One interesting issue is how to represent this textual
`content on the wrist watch computer to make it most
`accessible to the user.
`We chose to use Wireless Markup Language (WML) as
`the text format on the watch. Besides being an emerging
`standard that is expected to be widely accepted, WML has
`the additional desirable feature of being an XML
`document type and therefore supports the notion of
`hyperlinks, an intuitive and well accepted navigation
`model. We expect WML to be a standard format for
`publication of content for small form-factor devices like
`cellular phone, and hope to be able to use such content on
`the watch without change.
`All textual information on the wrist watch computer
`such as list of appointments, todo lists, email messages,
`etc., are stored as WML cards. Typically such information
`will be resident on a PC or other servers. As part of the
`synchronization software that extracts this information and
`sends it into the wrist watch computer, the information will
`be transcoded into WML along with the appropriate
`hypertext links. For example, a calendar entry can be
`scanned for people's names and the names are turned into
`WML hyperlinks that point to the corresponding cards in
`the address book.
`In addition, each calendar entry is
`automatically linked with the previous and next entries to
`aid in the navigation.
`When the watch displays WML content, rolling the
`wheel causes the current highlight to jump from hyperlink
`to hyperlink in the appropriate direction. Clicking the
`wheel in causes an activation of the hyperlink, i.e.,
`navigation to the card pointed to by the hyperlink.
`
`6 Applications
`
`We surveyed prospective wrist watch computer users,
`who told us they would like to see watch functions
`information management (PIM) application~
`personal
`(calendar, phone book, to dos), games, and an MP3 music
`player, on the wrist watch computer. Access to data from
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`the web was cited as an important application as well.
`This included alerts, stock quotes, sports scores, email
`headers, headline news, weather and traffic reports etc.
`We have
`implemented an prototype application
`environment for the wrist watch computer and have
`created
`several of
`the
`requested applications. The
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`Figure 3: Clock Face
`
`following sections discuss some of the above applications.
`With the power of such a device, one can easily imagine
`more applications,
`some highly personalized,
`some
`customized to games and trivia, etc.
`
`6.1 Clock face
`
`The primary display on the wrist watch is a clock face
`showing current time and date (see Figure 3). This is the
`default screen to which we come back to when the
`return-to-home function is invoked by tapping on the top
`left zone on the touch panel.
`On the clock face screen we decided that the top right
`touch zone should provide access to alarms, and the
`bottom right region should access the phone book since
`these are likely to be the most common applications. As
`discussed earlier,
`the top left zone in this screen will
`present the main menu or the application launch pad.
`Rolling the roller wheel will cycle through the days
`schedule. Pressing the roller wheel will provide access to
`the quiet time function (discussed below). This allocation
`allows one action access to key functions of the device -
`calendar, phone book, alarms, and turning off alarms.
`
`6.2 Icon ring - application selector
`
`The set of applications on a watch is expected to be
`quite small for any given person, perhaps of the order of a
`dozen or so. In keeping with the circular metaphor and
`using the roller wheel for most interactions, we chose to
`represent the application menu by means of icons that we
`position around a circle as shown in Figure 4.
`The
`user
`can
`roll
`the wheel
`clockwise or
`counterclockwise to move the selection from one icon to
`another. Once the desired icon is selected, the user clicks
`the roller wheel in to launch the application.
`It
`is quite difficult
`to create culture-neutral,
`self-evident icons that unambiguously convey functional
`purpose. The small size and limited color depth of the
`
`11
`
`wrist watch computer display makes this even more
`difficult. It is generally quite difficult to design such icons
`unless one has color pixels and a reasonable physical area
`for the icons. As a result, it is important for functional
`icons to have captions that explain their function.
`Users will initially rely on the caption, but gradually
`become familiar with the icons and use them directly.
`Since the screen dimensions are small, we cannot show all
`icons and their captions at the same time. Though icons
`can be small, the caption font has to be proportionally
`quite large to be legible. Therefore we chose to display
`just the caption for currently highlighted icon in the center
`of the icon ring. As the user rolls the wheel to move the
`highlight, the caption changes accordingly.
`Based on user experiments, we restricted the number of
`icons shown on a screen to eight. If there are more than
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`eight applications, we can place them on consecutive menu
`pages that. one can access by touching the top right or
`bottom right zones of the touch screen to go to the
`previous page or next page of applications respectively.
`Initial experience with this environment leads us to
`believe that users will be able to navigate to the right
`application page by tapping in corners of the wrist watch
`computer without looking at the display. For instance if a
`user has two application screens and knows that the
`application of interest is in the second page a top left tap
`followed by a bottom right tap will get the user to the
`appropriate menu page.
`Once in the right page, the user will have to look at the
`display while he selects the application icon by rolling the
`wheel and launches it by clicking the wheel. On any menu
`screen we put the most commonly used application in that
`screen as the default highlighted item.
`In this case, the
`user does not even have to look at the screen to launch his
`application, he just has to count the number of screen taps
`and follow it with a wheel click.
`
`6.3 Alarms
`
`An alarm can be associated with a specific time, a
`calendar entry, a to do entry, and to software agents either
`running on the watch or remotely.
`Alarms associated with time can be set by adjusting the
`hour first and then adjusting the minute hand. Alarms can
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`Figure 5: Alarm Message
`
`be set relative to the current time or on an absolute basis.
`For example, relative alarms are useful to remind people to
`shut the stove off in twenty minutes. A bell is displayed on
`the screen at the time for which the alarm is set, e.g., an
`alarm for 7 AM will be represented by a bell at the 7 AM
`position on the clock face.
`When an alarm is activated the wrist watch computer
`plays a sound on the speaker and presents the associated
`message title if any, on the display.
`In addition to the
`message title, options to acknowledge, snooze, and delete,
`are depicted as shown in Figure 5. The "acknowledge
`(OK)" option is highlighted when the alarm rings.
`When the alarm is ringing,
`the user can silence it by
`touching any part of the touch screen or by rotating the
`roller wheel or even by pressing in the roller switch. The
`focus here is to quickly silence the alarm since this is the
`first thing that the user would want to do.
`After the alarm has been silenced the watch will
`continue to display the message title associated with the
`alarm for some time interval, say 30 seconds. If the user
`taps on the touch screen again within these 30 seconds, the
`user acknowledges the alarm and the alarm is canceled.
`Once an alarm is canceled, the message is removed from
`the screen and the watch reverts back to showing the
`current time.
`If the user does not tap the alarm a second time within
`the specified duration, and does nothing,
`the alarm
`message title disappears and the alarm is automatically
`snoozed, i.e., the alarm will ring again after a snooze
`interval.
`The user also has the ability to proactively snooze the
`alarm without waiting for the time-out by rolling the wheel
`to highlight the snooze option and clicking the wheel to
`select it. The alarm text may also have hyperlinks to other
`pieces of information (for example a name in the message
`text may be a hyperlink to the person's phone number) that
`the user may navigate to by selecting the link and clicking
`the wheel.
`The salient part of this user interface to alarms is the
`consistency and simplicity of actions the user needs to take
`to silence, snooze or view the details for the alarm. A
`single tap silences the alarm, a double tap cancels the
`alarm, a single tap and time-out snoozes the alarm.
`Single or double taps on the watch face do not require
`the user to even look at the watch and can be done while
`
`doing other things such as engaging in a conversation,
`reading a newspaper, etc. Using a tap followed by a roller
`wheel and click can launch other actions, but in this case
`the user needs to pay more attention to the watch, i.e., look
`at it. Still if the list of possible options is small the amount
`of user distraction is minimal.
`
`6.4 Quiet Time
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`Figure 6: Quiet Time
`
`We allow the user to set a quiet time from the clock
`face screen.
`It is activated by pressing the roller wheel.
`This application quickly allows the user to turn off audible
`alarms until a specified time as shown in Figure 6. The
`time is specified by rolling the wheel to the desired time
`and pressing the roller wheel. Once the quiet time elapses
`the alarms are re-enabled automatically and any pending
`alarms are sounded.
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`Figure 7: Alphabet Selector
`
`6.5 Alphabet Selector
`
`Since the wrist watch computer has no keyboard, text
`must be entered with either the roller wheel or the touch
`screen. We do not expect the user to enter much text, but
`some will be required. We are testing one text input model
`as part of the name and address book application.
`In
`these situations all
`textual
`input must be
`accomplished using the roller wheel or the touch screen.
`When the user needs to look up a phone number the
`user is presented with a screen that looks like the one
`shown in Figure 7. The letters from A through Z are
`presented in a pair of concentric circles. We had to put the
`letters in two circles since putting them all on one circle
`made it look very cluttered and hampered readability.
`As the user rolls the wheel the selection cursor moves
`from character to character.
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`Once the user has the highlight on the right character,
`in
`the roller wheel causes phone numbers
`pushing
`corresponding to all names that begin with that letter to be
`displayed. These can then be scrolled though with the
`roller wheel. The advantage of placing the letters in this
`fashion is
`that the user can quickly select the desired
`character without much difficulty. The user can perceive
`at a glance where the desired character is located and
`simply roll the wheel, peripherally observing the highlight
`till it gets into the vicinity of the desired character. At this
`point a marginally higher level of concentration is required
`to match up the highlight with the desired character.
`The same scheme could be used to provide longer input
`strings to the watch that consist of say alphabets, numbers
`and a limited set of punctuations (to enter a phone number
`for example).
`
`6.6 Calendar
`The high resolution display allows a complete month
`
`To do lists can be shown as in Figure I 0. These to do
`lists are typically created on a PC or other device. Items
`can be checked off by pushing
`the roller wheel after
`It would be
`positioning the highlight on the right item.
`simple to have a predefined set of to dos in the watch and
`then allow the user to create a list from the predefined list.
`The predefined list could be personalized and downloaded
`in to the watch.
`
`6.8 Images
`
`Since we are designing for a high resolution display, we
`can easily display
`images on
`the watch, such as
`photographs of one's family members for example. We do
`not support gray scale or color in the initial versions of the
`watch, however, it is quite easy to simulate gray scale
`
`i
`
`November 1999
`...,,..
`Su Mo Tu We Th Fr Sa
`0 2 3 4 5 6
`7 8 9 10 11 12 13
`14 15 16 17 18 19 20
`21 22 23 24 25 26 27
`28 29 30 -
`-
`-
`-
`Oct 1999-
`Dec 1999
`~ - - - - ~ -
`
`Figure 8: Calendar Month View
`
`view to be displayed on the watch as shown in Figure 8.
`Scrolling past the last day of the month gets you to the
`next month and scrolling past the first day of the month
`t
`
`Thu Nov 11, 1999
`~
`16 00- Michael Karas1ck to v
`17-15 Pick up kids by 6 pm
`Next
`
`<If::_ ___ ~ - - -
`
`Figure 9: Calendar Day View
`
`to the previous month. The next month and
`gets you
`previous month hyperlinks get you there as well. Upon
`selection of a particular day, the day view shown in Figure
`9 is displayed.
`
`6.7 To Do list
`
`t
`
`ToooL1st
`~Implement Todo List
`!Alarm Browser
`✓ Reserve conference rooms
`
`=~
`
`✓Wheel mouse on thinkpad
`ITh1nkpad display problem
`~Fix 1lleg1ble font
`
`Figure 10: To Do List
`
`13
`
`Figure 11: Family Photo
`
`using spatial dithering. Since the display has a very fine
`
`Figure 12: Dilbert Cartoon
`
`dot pitch, the dithering is normally not perceptible to the
`human eye.
`In addition to photographs, one can easily load images
`such as cartoon strips into the watch and read them for
`amusement. Figures 11 and 12 show the results.
`
`6.9 Games - Tetris
`'•
`e
`
`Next Item
`
`-D
`•
`
`...
`Score.70 r
`
`Level O (cid:127)
`, • ...
`Rowso;
`j
`Move_:~
`
`. -.
`
`Figure 13: Tetris
`It was interesting to see if we could use the limited
`input function on the wrist watch computer to support a
`
`7
`
`

`

`game. We found a public implementation of a game
`similar to Tetris™ and found we were able to map it to the
`wrist watch computer controls. To play a game like
`Tetris™ one needs to be able to both move as well as
`rotate falling pieces. In addition, players like the ability to
`drop a falling piece quickly once it is in the correct
`position and orientation. The ability to pause and resume
`the game is also an important requirement.
`Given the limited input capabilities of the watch, it is a
`challenge to accomplish all of the above controls. The way
`we solved this problem is to map movement and rotation
`to the roller wheel and pause/resume and drop functions to
`the touch screen.
`The roller wheel can be in one of two modes, rotate or
`move. If it is in the rotate mode turning the wheel rotates
`the piece in the direction the wheel was rotated. If the
`wheel is in the move mode, turning the wheel moves the
`piece to the left or right. One can switch the mode of the
`wheel between rotate and move by clicking it in. When a
`new piece starts falling the wheel always reverts to the
`rotate mode since in our observations of Tetris players we
`noticed that they first oriented the piece the right way, then
`moved it and usually dropped it. However, this is not
`always true and sometimes one rotates the piece moves it
`and then changes ones mind, rotates it again to a new
`orientation and may move it again. For this reason till the
`piece actually hits the bottom one is allowed to alternate
`modes by clicking the wheel in. Admittedly this is a bit