Input device having a presence sensor

A system and method for reducing power consumption of a wireless input device is disclosed. The input device may convert between a high power state and a low power state. In the high power state, a transmitter and light sources are activated, whereas both the transmitter and the light sources are deactivated in the low power state. Following a period of inactivity in which neither a key sensor for activatable keys nor a presence sensor for the user transmit input, the input device may convert from the high power state to the low power state to conserve energy. When the presence sensor detects the presence of the user, however, the input converts to the high power state wherein the transmitter and the light sources are activated.

BACKGROUND

A variety of data entry techniques have been developed to enhance usability and to make computers more versatile. A typical computing environment, especially a computing environment incorporating graphical user interfaces for user interaction, may be optimized for accepting input from one or more discrete input devices. As an example, an individual may enter characters (i.e., text, numerals, and symbols) with a keyboard and control the position of a pointer image on a display with a pointing device, such as a mouse or trackball. A computing environment incorporating graphical user interfaces may also accept input though one or more natural input methods, including speech input methods and handwriting input methods. With regard to speech input methods, the phonemes of speech are input with a microphone and analyzed to convert the speech to typewritten text. With handwriting input methods, a pen-like stylus may be utilized to serve the general purpose of a pointing device and create electronic ink, which is analyzed to convert the handwriting into typewritten text.

Wireless connections are utilized in some input devices, particularly keyboards and pointing devices, to transmit data from the input devices to a computer. A variety of conventional wireless technologies may be utilized to transmit data from the input devices to a computer, including infrared, radio frequency, and BLUETOOTH technologies, for example. Whereas conventional wired input devices utilize a power/data cord to transmit data and supply power, wireless input devices rely upon battery power sources that are periodically replaced or recharged. In order to increase the intervals between replacing or recharging battery power sources, wireless input devices may employ power management states to conserve energy.

Wireless input devices are often turned on for ready usability but left idle for significant periods of time. This presents an opportunity to reduce depletion of battery power through the use of power management states that conserve energy by disabling various power-consuming functions associated with the input devices. As an example, a wireless input device may have a high power state wherein data is continuously transmitted to a computer, and the wireless input device may have a low power state wherein the transmission of data is disabled. During periods where the input device is utilized to enter characters or move a pointer, for example, the input device will remain in the high power state. After a predetermined period of inactivity, however, the input device may switch to the lower power state (i.e., cease transmitting data) to conserve energy. Once the wireless input device detects user interaction, the input device may switch back to the high power state and reestablish the connection with the computer. As another example, optical pointing devices that utilize a light source may switch from a high power state, wherein the light source is illuminated, to a low power state, wherein the light source is not illuminated, after a predetermined period of activity to conserve energy. A potential drawback to utilizing power management states is that a delay may occur between a time when the input device detects interaction and then switches to the high power state. That is, a time period may be required for the input device to switch from the low power state to the high power state.

SUMMARY

An example of the invention is an input device having a housing, a plurality of activatable controls, a light source, a sensor, and a control device. The housing forms at least a portion of an exterior of the input device. The controls are accessible from the exterior of the input device. The light source is at least partially located within the housing to illuminate the activatable controls. The sensor detects a presence of a user, and the sensor is separate from the controls and at least partially located within the housing. In addition, the control device is coupled to the light source and the sensor, and the control device activates the light source upon detecting the presence of the user.

Another example of the invention is a wireless keyboard having a housing, a plurality of activatable controls, a first sensor system, a transmitter, and a second sensor system. The housing forms at least a portion of an exterior of the keyboard, and the housing defines (a) a forward edge positioned proximal a user during use of the keyboard, (b) a rearward edge positioned away from the user during use of the keyboard, and (c) a pair of side edges extending between the forward edge and the rearward edge. The activatable keys are depressible toward an interior of the housing, and the keys are accessible from the exterior of the keyboard. The first sensor system has at least one first sensor that detects activation of the keys. The transmitter transmits data associated with the activation of the keys. In addition, the second sensor system has at least one second sensor that detects a presence of a user. The at least one second sensor is located within the housing and proximal the forward edge, and the at least one second sensor is separate from the at least one first sensor.

Yet another example of the invention is a method including a step of determining a time delay for establishing a data connection between a wireless input device and a computer. A presence of a user proximal the wireless input device is detected. In addition, an intensity of a light source is increased during a time period substantially equal to the time delay.

DETAILED DESCRIPTION

Introduction

The following discussion and accompanying figures relate to input devices that incorporate a sensor for detecting a presence of a user. As discussed in the Background section above, wireless connections are utilized in some input devices to transmit data from the input devices to a computer, and the input devices utilize battery power sources that periodically require replacement or recharging. In order to reduce depletion of the battery power sources, power management states are utilized to conserve energy by disabling various power-consuming functions associated with the input devices. One disadvantage in the use of power management states relates to time delays. More particularly, a delay occurs between the time when the input device detects user interaction and the time when the connection with the computer is reestablished. As discussed in greater detail below, input devices may decrease the time delay by positioning sensors at locations that detect the presence of the user at a relatively early time, or input devices may incorporate light sources that provide feedback to the user regarding the connection between the input device and the computer.

Exemplary Computing System Environment

FIG. 1illustrates a schematic diagram of a general-purpose digital computing environment that can be used to implement various aspects of the invention. InFIG. 1, a computer100includes a processing unit110, a system memory120, and a system bus130that couples various system components including the system memory120to the processing unit110. The system bus130may be any of several types of bus structures including a memory bus or memory controller, a peripheral bus, and a local bus using any of a variety of bus architectures. The system memory120may include read only memory (ROM)140and random access memory (RAM)150.

A basic input/output system160(BIOS), containing the basic routines that help to transfer information between elements within the computer100, such as during start-up, is stored in the ROM140. The computer100also may include a hard disk drive170for reading from and writing to a hard disk (not shown), a magnetic disk drive180for reading from or writing to a removable magnetic disk190, and an optical disk drive191for reading from or writing to a removable optical disk199, such as a CD ROM or other optical media. The hard disk drive170, the magnetic disk drive180, and the optical disk drive191are connected to the system bus130by a hard disk drive interface192, a magnetic disk drive interface193, and an optical disk drive interface194, respectively. These drives and their associated computer-readable media provide nonvolatile storage of computer-readable instructions, data structures, program modules, and other data for the personal computer100. It will be appreciated by those skilled in the art that other types of computer-readable media that can store data that is accessible by a computer, such as magnetic cassettes, flash memory cards, digital video disks, Bernoulli cartridges, random access memories (RAMs), read only memories (ROMs), and the like, may also be used in the example operating environment.

A number of program modules can be stored on the hard disk drive170, the magnetic disk190, the optical disk199, the ROM140, or the RAM150, including an operating system195, one or more application programs196, other program modules197, and program data198. A user can enter commands and information into the computer100through input devices, such as a keyboard101and pointing device102(such as a mouse). Other input devices (not shown) may include a microphone, joystick device, game pad, satellite dish, scanner, or the like. These and other input devices are often connected to the processing unit110through a serial port interface106that is coupled to the system bus130, but they also may be connected by other interfaces, such as a parallel port, game port, BLUETOOTH or other wireless connections, or a universal serial bus (USB), and the like. Further still, these devices may be coupled directly to the system bus130via an appropriate interface (not shown).

A monitor107or other type of display device also may be connected to the system bus130via an interface, such as a video adapter108. In addition to the monitor107, personal computers typically include other peripheral output devices (not shown), such as speakers and printers. In one example, a pen digitizer165and accompanying pen or stylus166are provided in order to digitally capture freehand input. Although a connection between the pen digitizer165and the serial port interface106is shown inFIG. 1, in practice, the pen digitizer165may be directly coupled to the processing unit110, or it may be coupled to the processing unit110in any suitable manner, such as via a parallel port or another interface and the system bus130as is known in the art. Furthermore, although the digitizer165is shown apart from the monitor107inFIG. 1, the usable input area of the digitizer165may be co-extensive with the display area of the monitor107. Further still, the digitizer165may be integrated in the monitor107, or it may exist as a separate device overlaying or otherwise appended to the monitor107.

The computer100can operate in a networked environment using logical connections to one or more remote computers, such as a remote computer109. The remote computer109can be a server, a router, a network PC, a peer device or other common network node, and it typically includes many or all of the elements described above relative to the computer100, although for simplicity, only a memory storage device111has been illustrated inFIG. 1. The logical connections depicted inFIG. 1include a local area network (LAN)112and a wide area network (WAN)113. Such networking environments are commonplace in offices, enterprise-wide computer networks, intranets, and the Internet, using both wired and wireless connections.

When used in a LAN networking environment; the computer100is connected to the local area network112through a network interface or adapter114. When used in a WAN networking environment, the computer100typically includes a modem115or other means for establishing a communications link over the wide area network113, such as the Internet. The modem115, which may be internal or external to the computer100, may be connected to the system bus130via the serial port interface106. In a networked environment, program modules depicted relative to the personal computer100, or portions thereof, may be stored in the remote memory storage device.

Although theFIG. 1environment shows an illustrative environment, it will be understood that other computing environments also may be used. For example, one or more examples of the invention may use an environment having fewer than all of the various aspects shown inFIG. 1and described above, and these aspects may appear in various combinations and subcombinations that will be apparent to one of ordinary skill.

Input Device Structure

With reference toFIG. 2, the keyboard101is depicted individually as having a housing201and a plurality of activatable keys203that are accessible from an exterior of the keyboard101. As is well-known in the art, one purpose of the keyboard101is to selectively enter data, which generally takes the form of a plurality of characters, such as alphabetic characters, numerals, punctuation marks, or one of the various symbols that are commonly utilized in written text (e.g., $, #, %, &, or @). In addition, the keyboard101may perform various functions, such as executing software applications, controlling power states in the computer100, or controlling the position of a pointer or cursor, for example. By depressing or otherwise activating the various keys203, the user may enter characters or perform the various functions.

The housing201defines various edges that include a forward edge205a, a rearward edge205b, and a pair of opposite side edges205c. Although the keyboard101may be oriented in a variety of ways relative the user, conventionally the forward edge205ais positioned proximal the user during use of the keyboard101and the rearward edge205bis positioned away from the user during use of the keyboard101. In addition, the side edges205cextend between the forward edge205aand the rearward edge205b.

The housing201encloses various components that include a key sensor207, various light sources209, a transceiver211, a presence sensor213, a power source215, and a microprocessor217, as depicted schematically in the cross-section ofFIG. 3. In addition to these components, the housing201may also enclose other elements, including a pointing device (e.g., touchpad or trackball assembly) for moving a pointer on the monitor107, a mechanical system for modifying the orientation of the keyboard101relative to the user, and an activation (i.e., on/off) switch for the keyboard101. Accordingly, the keyboard101may include a variety of relatively conventional elements not specifically discussed herein.

Key sensor207extends under each of the keys203and detects activations of the various keys203. More particularly, when the keys203are depressed or otherwise activated, the key sensor207detects the actuations and transmits a corresponding signal to microprocessor217. The key sensor207may have the configuration of a conventional membrane sensor system, as disclosed in U.S. Pat. No. 6,323,445 to Yee. Alternately, the key sensor207may have the configuration of a capacitive sensor that detects activations of the various keys203, or other suitable sensor systems may be employed.

The light sources209are located under the keys203and provide backlighting that illuminates the keys203. When utilizing the keyboard101in a darkened environment, light sources209permit the user to visually-distinguish the various keys203from each other and also determine the characters or functions associated with the keys203. As an example, the keys203may be at least partially transparent such that illumination from the light sources209passes through the keys203and permits the user to see the character or function identifiers associated with the keys203. Although the light sources209are depicted as being positioned below the key sensor207, the light sources209may also be located between the keys203and the key sensor207. In addition to illuminating the keys203, the light sources203may provide visual queues as to whether various functions are activated, such as CAPS LOCK, SCROLL LOCK, and NUMBER LOCK, for example, or the light sources203may indicate whether the keyboard101is turned on or otherwise active. In some configurations of the keyboard101, the light sources209may be omitted or utilized for other functions. In further configurations, the degree to which the light sources209illuminate may be related to the amount of light around the keyboard101, as detected by the presence sensor213or another sensor.

The transceiver211has a generally conventional configuration that wirelessly transmits data to the computer100and may also receive data from the computer100. For example, when one of the keys203is activated, the transceiver211wirelessly sends a corresponding signal to the computer100indicating that a particular character should be entered or that a particular function should be performed. In some configurations of the keyboard101, a conventional cord-style connection that carries both power and data may replace the transceiver211. In some configurations, transceiver211may have the configuration of a transmitter, with a receiver being a separate component. In further configurations, the keyboard101may only include a transmitter.

The presence sensor213detects changes in the environment due to the presence of the user proximal to the keyboard101. Accordingly, the presence sensor213may detect changes in the electric field, magnetic field, electromagnetic field (e.g., light), sound; and temperature, for example. As discussed in greater detail below, the keyboard101may employ various power management states that conserves energy in the power source215. More particularly, the light sources209and the transceiver211may be deactivated after a period of inactivity to increase the length of time that the power source215may be utilized between recharging or replacement. When the presence sensor213detects movement of the user, the light sources209and the transceiver211may be activated to provide the user with illumination of the keys203and a connection between the keyboard101and the computer100. Although the presence sensor213is depicted as being a separate sensor than the key sensor207, the presence sensor213and the key sensor207may be a single sensor or sensor array in some configurations of the keyboard101.

With reference toFIG. 4, the presence sensor213is depicted as having a first portion219aand a second portion219bthat are joined by a connecting portion219c. First portion219aincludes a sensing region221a, and second portion219bincludes a pair of sensing regions221b. The presence sensor213may be formed from a film of polymer material that includes various conductive leads223extending from the sensing regions221aand221bto a connector225, which electrically-connects the presence sensor213to the microprocessor217. Accordingly, the sensing regions221aand221btransmit signals to the microprocessor217through the leads223. The sensing regions221aand221bare capacitive sensors that may detect the presence of the user without physical contact between the user and the keyboard101. Although the range of the sensing regions221aand221bmay vary significantly, the sensing regions221aand221bmay detect when a portion of the user (e.g., the user's hand) is within four inches, for example, of the keyboard101through changes in capacitance. In addition to capacitive sensors, the sensing regions221aand221bmay be infrared sensors, ultrasonic sensors, or acoustic sensors, for example. Accordingly, a variety of sensor types may be utilized for the presence sensor213.

The presence sensor213is located within the housing201such that the sensing region221ais proximal to the forward edge205aand the sensing regions221bare proximal to the side edges205c. More particularly, the first portion219aand the second portion219bare folded relative to each other at the connecting portion219c, as depicted inFIG. 3. This configuration locates the first portion219aadjacent an upper area of the housing201and proximal to the forward edge205a. In addition, the second portion219blays adjacent a lower area of the housing201such that portions including the sensing regions221bextend rearward and along the side edges205c. In general, therefore, the sensing regions221aand221bare respectively located adjacent the edges205aand205c, which form a portion of a periphery of the keyboard101.

The power source215is located within the housing201and provides energy to each of the key sensor207, the light sources209, the transceiver211, the presence sensor213, and the microprocessor217. The power source215may be either rechargeable batteries or replaceable, non-rechargeable batteries, for example. In configurations wherein a conventional cord-style connection that carries both power and data is utilized, the power source215may be absent from the keyboard101.

The microprocessor217effectively controls the operation of the keyboard101. With reference toFIG. 5, the manner in which the keyboard101operates will be discussed in greater detail. In general, the microprocessor217receives input from both the key sensor207and the presence sensor213, and the microprocessor217directs operation of the transceiver211and the light sources209based upon this input. In addition, the transceiver211is wirelessly connected to the computer100and transmits data to the computer100and may receive data from the computer100.

Power Management States

The transceiver211and the light sources209require energy and may deplete the power source215, thereby requiring that the power source215be replaced or recharged. In order to reduce depletion of the power source215, power management states are utilized to conserve energy by disabling various power-consuming functions associated with the keyboard101. For example, one or both of the transceiver211and the light sources209may be deactivated following a time period in which neither the key sensor207nor the presence sensor213provide input to the microprocessor217. That is, after a period of inactivity by the user, the microprocessor217may (a) disable the wireless connection between the transceiver211and the computer100and (b) turn off the light sources209to conserve energy in the power source215.

Based upon the above discussion, the keyboard101includes at least two power management states. When the keyboard101is in a high power state, both the transceiver211and the light sources209receive energy and are activated. When the keyboard101is in a low power state, however, neither the transceiver211nor the light sources209receive energy and are effectively deactivated. In addition to the high power state and the low power state, the keyboard101may have various intermediate power states wherein one of the transceiver211and the light sources209are activated, or the light sources209may be dimmed, for example.

As an example of the manner in which the keyboard101operates, assume that the keyboard101is in the high power state and both the transceiver211and the light sources209receive energy and are activated. This may occur immediately following activation of the keyboard101(e.g., by turning the keyboard101on) or while the user is typing on the keyboard101. In the high power state, the transceiver211wirelessly connects the keyboard101to the computer100and the light sources209illuminate the keys203. If the user activates one of the keys203, the microprocessor217receives input from the key sensor207and directs the transceiver211to send data to the computer100. As discussed above, the data may direct that various characters be entered or that various functions be performed, depending upon the specific keys203or combinations of keys203that are activated. Also, if the user activates one of the keys203, the microprocessor217receives input from the presence sensor213based upon the proximity of the user (e.g., the user's hands) to the keyboard101.

Following a period of inactivity wherein the microprocessor217does not receive input from either of the key sensor207and the presence sensor213, the keyboard101may convert from the high power state to the low power state to conserve energy in the power source215. More particularly, the microprocessor217may (a) disable the wireless connection between the transceiver211and the computer100and (b) turn off the light sources209. As long as the microprocessor217does not receive input from either of the key sensor207and the presence sensor213, the keyboard will remain in the low power state.

While in the low power state, if the microprocessor217receives input from either of the key sensor207and the presence sensor213, then the microprocessor217activates both of the transceiver211and the light sources209. Accordingly, the transceiver211will wirelessly connect with the computer100and the light sources209will illuminate. One disadvantage in the use of power management states relates to time delays. More particularly, a delay occurs between the time when the keyboard101detects user interaction and the time when the connection with the computer100is reestablished. When the user attempts to utilize the keyboard101, the user's hands will generally move toward the keyboard101and will likely be detected by the presence sensor213. The presence sensor213will, therefore, provide input to the microprocessor217indicating that the user is present before physical contact is made between the user and the keyboard101. As noted above, the sensing regions221aand221bof the presence sensor213are respectively located adjacent the edges205aand205c, which form a portion of a periphery of the keyboard101. The sensing regions221aand221bare positioned, therefore, to detect the presence of the user as the user's hands approach the keyboard101. Accordingly, the time delay may be minimized by positioning sensing regions221aand221bat locations that detect the presence of the user at a relatively early time.

Upon detecting the presence of the user with the presence sensor213, the microprocessor217activates both of the transceiver211and the light sources209. Although the transceiver211may be activated, the wireless connection with the computer100may be delayed as the connection is reestablished. The light sources209may be utilized to provide feed back to the user regarding the state of the connection between the input device and the computer. Although the light sources may be immediately illuminated by the microprocessor211, illumination may be delayed until the connection with the computer100is reestablished so that the user does not activate the keys203prior to establishment of the connection. As an alternative, the illumination from the light sources209may be gradually increased during the time delay so that full illumination of the light sources209coincides with establishment of the connection.

Once the transceiver211establishes a connection with the computer100and the light sources209are illuminated, the keyboard is returned to the high power state. The user may then activate the keys203to enter characters or perform functions. If a period of inactivity follows, however, the keyboard101may return to the low power state. Accordingly, the keyboard101changes between the high power state and the low power state depending upon whether input is received by the microprocessor217from the key sensor207and the presence sensor213. In this manner, energy associated with the power source215may be conserved.

In addition to reducing time delays, the keyboard101may also assist the user in various darkened or low light environments. For example, the user may not be able to distinguish between individual keys203. By moving a hand proximal to the keyboard101, light sources209are illuminated to assist the user with seeing the keys203. That is, the system discussed above for the keyboard101may be utilized to assist users in seeing the keys203. before having to depress the keys203while typing or otherwise utilizing the keyboard101.

Flow Diagram Discussion

An enhanced understanding of the system discussed above may be gained through reference toFIG. 6, which discloses a flow diagram illustrating steps performed in executing various aspects of the invention. Initially, the keyboard101is activated (Step301), which may occur when the keyboard101is turned on or when power source215is installed, for example. The wireless connection between the keyboard101and the computer100is then established (Step303). Upon receiving power, the transceiver211sends a signal to the computer100that establishes the connection between the computer100and the keyboard101, thereby permitting data from activating keys203to be transmitted to the computer100. In addition to establishing the connection between the keyboard101and the computer100, light sources209are illuminated (Step305).

At this stage of the process, the keyboard101is in the high power state. Following a period of inactivity, however, the keyboard101converts to the low power state. The period of inactivity that precedes the conversion from the high power state to the low power state may be predetermined or set by the user. A counter is set, however, to the period of inactivity (Step307) and begins counting down. If input is received from the key sensor207(Step309), then data associated with the input is transmitted (Step311). More particularly, when microprocessor217receives input from the key sensor207due to activation of one of the keys203by the user, the microprocessor directs the transceiver211to send data associated with the activation to the computer100. Because the receipt of input from the key sensor207indicates user interaction with the keyboard101, the counter (from Step307) is reset to begin the period of inactivity. If input is received from the presence sensor213(Step313), the counter (from Step.307) is again reset to begin the period of inactivity. Accordingly, either input from the key sensor207or the presence sensor213resets the counter. In some configurations of the keyboard101, only input from the presence sensor213will reset the counter.

If input is not received from the key sensor207or the presence sensor213, then the microprocessor217determines whether the counter has reached zero (Step315). In circumstances where the counter has not reached zero, the microprocessor continues to seek input from the key sensor207or the presence sensor213. If, however, the counter has reached zero, the microprocessor217disables the wireless connection by reducing power to the transceiver211and also disables the light source209(Step317). More particularly, the keyboard101converts from the high power state to the low power state. In effect, therefore, when the period of inactivity expires, the keyboard101converts from the high power state to the low power state to conserve energy in the power source215.

When in the low power state, the microprocessor continues to seek input from the key sensor207or the presence sensor213(Step319). If no input is received, the keyboard101remains in the low power state. If input is received, however, from either of the key sensor207or the presence sensor213, then the microprocessor217enables the wireless connection, illuminates the light source209, sets the counter, and the process continues as discussed above.

Based upon the above discussion, the keyboard101remains in the high power state until a period of inactivity expires. Following the period of inactivity, the keyboard101converts to the low power state until input is received from either of the key sensor207or the presence sensor213. If no input is received, the keyboard101remains in the low power state. When input is received, the keyboard101converts back to the high power state so that activations of the various keys203result in data being transmitted to the computer100.

Increasing Illumination

A time delay occurs between the time when the microprocessor217directs the transceiver211to establish a connection with the computer100and the time when the connection is fully established. If the user activates keys203during this time delay, characters or functions associated with the activations may not be immediately transmitted to the computer100, which results in undesirable latency. In order to provide the user with feedback on whether the connection has been established, the illumination from the light sources209may be gradually increased during the time delay so that full illumination of the light sources209coincides with establishment of the connection. Accordingly, the user will learn to wait until the light sources209have reached full illumination prior to activating the keys203. Given that the presence sensor213detects the presence of the user prior to physical contact between the user and the keyboard101, light sources209may begin to illuminate before physical contact is made.

The time delay may range from fractions of a second to multiple seconds, depending upon various factors. In order to effectively time the gradual increase in illumination of light sources209, the delay may be predetermined based upon averages for various systems or the keyboard101may calculate the time delay, for example. Once the delay is determined and presence of the user proximal the keyboard101is detected, the intensity of the light source209may be increased during a time period substantially equal to the time delay. As noted above, the increasing illumination provides the user with feedback on whether the connection has been established.

Additional States

The keyboard101is discussed above as having the high power state and the low power state. Other configurations of the keyboard101may have an intermediate state wherein the light sources209are deactivated, but the transmitter remains activated. For example, if no input is received from the key sensor207or the presence sensor213, the keyboard101converts to the intermediate power state wherein the light sources209are deactivated to conserve energy that would be utilized to illuminate the power sources209. In the intermediate power state, the transceiver211remains activated and the connection with the computer100remains. After a further delay, however, the transceiver211is deactivated. That is, if no input is received from the key sensor207or the presence sensor213after a further delay, then the keyboard101may convert to the low power state.

With reference toFIG. 7, a state diagram illustrating various additional states for the keyboard101is depicted. In each of the states, various degrees of power are utilized. A dormant state401is substantially similar to the low power state discussed above. In the dormant state401, the light sources209and the transceiver211are in low power operation, and the key sensors207may also be in low power operation. The dormant state401may have multiple sub-states where the level of activity (and power consumption) may increase temporarily. For example when an initial change in the presence sensor213is observed, the sample rate may increase in order to provide a better discrimination of true user presence and background noise. Input from the presence sensor213indicating user presence may be qualified by the number of times that the presence sensor213has detected user presence (from a user absent state) without having the user actually use the keyboard101. For example, if more than three detections of user presence have occurred without the user actually using the keyboard101, the presence event may be ignored. This would assist in the event that the presence sensor213indicates false presence due to noise in the environment. Other events that would qualify for exiting of the dormant state401include input from key sensor207or other positive interaction with the keyboard101.

Once input from the key sensor207or the presence sensor213is received, the keyboard101enters a start radio link state403. In this state, the wireless connection with the computer100is established. Start radio link state403corresponds, therefore, with step303discussed above.

Following the start radio link state403, the keyboard101may enter an update schedule state405, in which intervals for activation of the key sensor207, the light sources209, and the transceiver211are established. That is, the time periods during which the key sensor207, the light sources209, and the transceiver211remain active are determined and may be reflected in step307of the flow diagram. The time periods may depend on what types of events have been detected (i.e., user presence, key or button press or release, other sensors) as well as the status of the wireless connection, whether a cable connection is utilized to connect the keyboard101to the computer100, or the state of the power source215(i.e., is it being charged or running on batteries). The time periods may be updated on the occurrence of appropriately qualified events that include user interactions with the keys203, input from the key sensor207and the presence sensor213, user presence or absence changes, changes in the power source215, or changes in the wireless connection state.

The degree to which the keys203are illuminated by the light sources209depends upon whether the keyboard101is in a max backlight state407, a reduced backlight state409, or a no backlight state411. Following positive interaction between the user and the keyboard101, for example, the keyboard101may convert to the max backlight state407to provide maximum illumination for the keys203. After an interval of inactivity, the keyboard101may convert to the reduced backlight state409, wherein the keys203are illuminated to a lesser degree. After a longer period of inactivity, the keyboard101may convert to the no backlight state411. The time periods for each of states407,409, and411may be determined during the update schedule state405based upon the various events discussed therein.

The time period during which the transceiver211retains the wireless connection with the computer100may also be determined during the update schedule state405based upon the various events discussed therein. Following a period of inactivity, the keyboard101may enter a break radio link state413, which effectively returns the keyboard101to the dormant state401. That is, after a sufficient period of inactivity, the keyboard101enters the low power state, wherein energy is conserved.

Pointing Device Configurations

With reference toFIG. 8, a pointing device500having the configuration of a mouse is depicted. The pointing device500includes a primary key501aand a secondary key501bthat are located on opposite sides of a scroll wheel503. In addition, a conventional tracking assembly (not depicted) that may include a roll ball or optical tracking system is incorporated into the pointing device500. As with keyboard101, the pointing device500may be a wireless input device that incorporates a presence sensor and a light source. The pointing device500may also include a power source that benefits from various power management states. Accordingly, the pointing device500may have a high power state wherein the wireless connection and the light sources are activated, and the pointing device500may have a low power state wherein the wireless connection and the light sources are deactivated. In addition to a mouse, a trackball pointing device may include similar features.

Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims. Numerous other embodiments, modifications and variations within the scope and spirit of the appended claims will occur to persons of ordinary skill in the art from a review of this disclosure.