Abstract:
Method and apparatus for transitioning an electronic device operable in a reduced power consumption mode from the reduced power consumption mode to a full power mode immediately before a user attempts to operate the device is disclosed. A hand held intelligent data entry unit (IDEU) of the present invention is provided with a noncontact sensor for detecting the prepense of a user&#39;s hand within an predefined actuation region of the IDEU while the IDEU is operating in a low power consumption mode. Responsive such detection, the sensor generates a wake up signal to a microprocessor of the IDEU for causing the IDEU to transition from the low power consumption mode to a full power mode.

Description:
TECHNICAL FIELD 
     The invention relates generally to devices that are capable of operating in a reduced power consumption mode and, more particularly, for providing such devices with a noncontact sensor for use in causing the device to transition from the reduced power consumption mode to full power mode. 
     BACKGROUND OF THE INVENTION 
     Over the years, many attempts have been made to reduce the power consumption of battery powered electronic devices, thereby yielding longer battery operation. For obvious reasons, many of these attempts have focused on reducing the amount of power consumed by such devices while the device is on, but not in use. Hence, a reduction in power consumption has been achieved by slowing or stopping certain components of the device after the device or devices have been inactive for a predetermined period of time, which may or may not be set by the user. Clearly, therefore, it is critical to maintaining proper device performance accurately to determine when to slow or power down the device without disrupting the user&#39;s work, until further operation is needed. 
     For example, in the field of portable personal computers, when a computer&#39;s disk drive has not been accessed for a predetermined amount of time, for example, two minutes, the drive is powered down or caused to operate in a reduced power consumption mode, often referred to as “standby mode,” such that the drive consumes less power, thereby reducing the overall power consumption of the computer. Thereafter, when a drive access is attempted, full power is reapplied to the drive and the drive spins up and is ready to be accessed. 
     Another example of a device capable of operation in a reduced power consumption mode is a device known as a radio mouse. Typically, after expiration of a predetermined amount of time in which the mouse has not been used, a microcontroller included in the mouse causes the mouse to operate in a reduced power consumption mode. This may be accomplished, for example, by writing the contents of a volatile memory device within the microcontroller, which is accessed by the microcontroller during operation of the mouse, to a nonvolatile memory device, which is slower than the microcontroller&#39;s volatile memory device. Power is then removed from the volatile memory device and is removed from or reduced to other components of the mouse. When the user is again ready to use the mouse, the user must move the mouse or click a mouse button provided thereon, at which point a signal is sent to wake up the mouse. 
     Although the above-described methods accomplish their primary goal, that is, to reduce in the amount of power consumed by the device, they suffer certain deficiencies, the most obvious of which is the time delay experienced by the user in waiting for the device to return to full power mode so that it can be used for its intended purpose. Referring to the disk drive example, the user must wait for power to be reapplied to the drive and the drive to spin up before access can be made thereto. With regard to the radio mouse, because the wake up signal is not sent until the user actually attempts to use the mouse to input data, the user may experience a delay of up to several seconds in inputting the data while the necessary operations for awakening the mouse are performed. 
     Hence, although it is possible for a user to wait for a device to return to full power state when he or she is again ready to use the device, it is not particularly desirable to require him or her to do so. On the other hand, there are inherent limits on the speed with which a device can be transitioned from a reduced power consumption to a full power mode. 
     Therefore, what is needed is a means for causing a device operating in a reduced power consumption mode to return to a full power mode immediately before the user is ready to use the device, such that the device has already returned to the full power mode by the time the user attempts to operate the device. 
     SUMMARY OF THE INVENTION 
     The foregoing problems are solved and a technical advance is achieved by a method and apparatus for transitioning an electronic device operable in a reduced power consumption mode from the reduced power consumption mode to a full power mode immediately before a user attempts to operate the device. In a departure from the art, a hand held intelligent data entry unit (IDEU) is provided with a noncontact sensor for detecting the presence of a user&#39;s hand within an actuation region of the IDEU during operation of the IDEU in the reduced power consumption mode and for sending a signal responsive to such detection for causing the IDEU to operate in full power mode. 
     In a preferred embodiment, the IDEU of the present invention comprises a microcontroller connected to one or more input devices, a nonvolatile memory device, a power supply comprising one or more batteries and a noncontact sensor, such as a capacitive sensor. In accordance with a feature of the present invention, the IDEU is operable in a full power, or active mode, in which all of the IDEU components are operating at normal levels, and in a reduced power consumption mode, in which the IDEU consumes significantly less power than it does during operation in the active mode. Accordingly, the microcontroller further includes a timeout timer, which, in the preferred embodiment, is a count-down timer that is initially set to expire after a predetermined amount of time, for example, 5 minutes, has elapsed and is reset responsive to input received by the microcontroller from one of the input devices. Upon the expiration of the predetermined amount of time without receipt of input from the devices, the timeout timer generates a “timeout” signal, causing the microcontroller to perform the operations necessary to place the IDEU in the reduced power consumption mode. 
     The capacitive sensor is arranged to detect the presence of a user&#39;s hand within a predefined “actuation region” of the IDEU and generate a “wake up” signal to the microcontroller responsive to the detection. The actuation region is ideally defined based on the amount of time required to wake up the computer, such that the IDEU can be caused to be ready to accept data via the input devices  22  as soon as the user picks up the IDEU. 
     A technical advantage achieved with the present invention is that it prevents the user from experiencing time delays typically associated with transitioning a device from a low power consumption mode to a full power mode. 
     A further technical advantage achieved with the present invention is that it can be used in connection with any number of different types of portable hand held electronic devices, such as intelligent remotes, radio mouses and the like. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a block diagram of a host system and associated hand held intelligent data entry unit (IDEU) embodying features of the present invention. 
     FIG. 2 is a state diagram of the operation of the IDEU of FIG.  1 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIG. 1, a hand held intelligent data entry unit (IDEU) embodying features of the present invention is designated by reference numeral  10 . The IDEU  10  is connected to a host system  12 , via a data communications link  14  and first and second interfaces  16  and  18 , respectively, for receiving data from and transmitting data to the host system  12 . In one embodiment, the data communications link  14  is a wireless link, such as a radio frequency (RF) or infrared (IR) link. In an alternative embodiment, the data communications link  14  is a physical link, such as a coaxial cable or other wiring means. In either case, it should be understood that the interfaces  16  and  18  will be of a type known in the art for enabling the selected mode of data transmission. 
     The IDEU  10  comprises a microcontroller  20  connected to one or more input devices, designated collectively by reference numeral  22 , nonvolatile memory device  24 , a power supply  26  comprising one or more batteries (not shown) and a capacitive sensor  28 . The host system  12  comprises at least a microprocessor  30  connected to a plurality of I/O devices, designated collectively by reference numeral  32 , and memory  34 . 
     In accordance with a feature of the present invention, the WDEU  10  is operable in a full power, or active, mode, in which all of the IDEU  10  components are operating at normal levels, and in a reduced power consumption mode, in which the IDEU  10  consumes significantly less power than it does during operation in the active mode. Accordingly, the microcontroller  20  further includes a timeout timer  36  and volatile memory, such as a static random access memory (SRAM)  38 . It should be understood that dynamic random access memory (DRAM) may also be used without departing from the scope of the present invention. In a preferred embodiment, the timeout timer  36  is a count-down timer that is initially set to expire after a predetermined amount of time, for example, 5 minutes, has elapsed and is reset responsive to input received by the microcontroller  20  from one of the input devices  22  via a line  40 . As is typically the case with devices that are operable in a low power consumption mode, upon expiration of the predetermined amount of time without receipt of input from the devices  22 , the timeout timer  36  generates a “timeout” signal. Responsive to the timeout signal, the microcontroller  20  performs the operations necessary to place the IDEU  10  in a reduced power consumption mode. 
     It should be understood that there are many methods known in the art for operating a device, such as the IDEU  10 , in a reduced power consumption mode; however, in an illustrative embodiment, this may be at least partially accomplished by the microcontroller&#39;s  20  writing the contents of the SRAM  38  to the nonvolatile memory device  24  and then removing power from the SRAM  38 , as well as other devices, if desired. The IDEU  10  remains in the reduced power consumption state until a “wake up” signal is received by the microcontroller  20  from the capacitive sensor  28  on a line  42 , as will be described below. 
     In a preferred embodiment, the capacitive sensor  28  is configured to sense an increase in the voltage drop across a reference capacitor (not shown) resulting from the presence of a user&#39;s hand within a predefined “actuation region” of the IDEU  10  and generate a “wake up” signal to the microcontroller  20  when the sensed voltage drop exceeds a preset threshold voltage. The threshold voltage is selected based on the amount of time needed to perform the operations necessary to return the IDEU  10  to full power mode, such that the more time required to awaken the IDEU  20 , which in the illustrative embodiment described above comprises at least reapplying power to the SRAM  38  and writing the contents of the nonvolatile memory device  24  back to the SRAM  38 , the lower the threshold voltage should be set, thereby to allow more time to awaken the IDEU  20 . In this manner, the IDEU  10  can be made ready to accept data via the input devices  22  as soon as the user picks up the IDEU  10 . 
     In one embodiment, the IDEU  10  is a radio mouse, in which case the input devices  22  include a trackball and mouse keys. In alternative embodiments, the IDEU  10  is an intelligent remote control unit, in which case the input devices  22  comprise a plurality of keys or toggle switches, or a joystick or other known pointing device. 
     In an extension of the present invention, the wake up signal generated by the capacitive sensor  28  on the line  42  may also be transmitted to the microprocessor  30  of the host system  12  (via the interface  16 , the data communications link  14  and the interface  18  to return the host system  12  to a full power mode from a reduced power consumption mode. 
     FIG. 2 is a state diagram of the operation of the IDEU  10  (FIG.  1 ). The IDEU  10  is operable in three states, including a reduced power consumption state  200 , an active, or full power, state  202 , and an inactive state  204 , which corresponds to a condition of the IDEU  10  in which batteries (not shown) comprising the power supply  26  (FIG. 1) have been removed or are depleted. 
     In the preferred embodiment, the IDEU  10  powers up in and is reset to the reduced power consumption state  200 , it being understood that this is a design choice only, and that the IDEU  10  could just as feasibly power up in and/or reset to the active state  202 . When the IDEU  10  is in the reduced power consumption state  200  and the capacitive sensor  28  (FIG. 1) generates a wake up signal to the microcontroller  20  (FIG.  1 ), the IDEU  10  transitions to the active state  202 , as indicated by an arrow  208 . When the IDEU  10  is in the active state  202  and the timeout timer  36  (FIG. 1) generates a timeout signal, the IDEU  10  transitions to the reduced power consumption state  200 , as indicated by an arrow  210 . When the IDEU  10  is in either the reduced power consumption state  200  or the active state  202  and the batteries (not shown) comprising the power supply  26  are removed or depleted, the IDEU  10  transitions to inactive state  204 , as indicated by arrows  212  and  214 , respectively. When the IDEU  10  is in the inactive state  204  and fresh batteries are inserted, the IDEU  10  transitions to the reduced power consumption state  200 , as indicated by an arrow  216 . 
     It is understood that the present invention can take many forms and embodiments. The embodiments shown herein are intended to illustrate rather than to limit the invention, it being appreciated that variations may be made without departing from the spirit or the scope of the invention. For example, any number of different types of “noncontact sensors,” including optical sensors, ultrasonic sensors, and passive infrared intrusion sensors, may be used in place of the capacitive sensor for sensing the approach of a user&#39;s hand toward the IDEU  10 . In addition, the wake up signal generated by the capacitive sensor  28  may also be provided to the microprocessor  30  for transitioning the host system  12  from a reduced power consumption mode to a full power mode. 
     Although illustrative embodiments of the invention have been shown and described, a wide range of modification, change, and substitution is intended in the foregoing disclosure and in some instances, some features of the present invention may be employed without a corresponding use of the other features. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention.