Abstract:
An alarm clock is mounted above a bed and uses a thermal sensor to identify the location of each person sleeping in the bed and to direct light and sound to only one of them for the purpose of selectively waking only that individual. A platform is driven to scan across the bed, and has an infrared sensor creating a temperature profile with a thermal signature indicating the position of each occupant. Platform electronics generate a narrow beam LED light, and an array of ultrasonic speakers serves as a parametric speaker producing a narrow sound beam heard only by the targeted sleeper. At a preset time the alarm is triggered and the platform is pointed at the targeted sleeper identified by his or her infrared thermal signature. The LED light is driven from low to high to simulate dawn. Following maximum brightness, the parametric speaker emits a wake-up audio.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
     Not applicable. 
     STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     The present invention relates to alarm clocks which awaken one person without disturbing others sleepers in the same bed or same room. 
     Alarm clocks have an ancient history, the philosopher Plato (428-348 BC) was said to possess a water clock which would wake him for his early lectures. The Buddhist monk Yi Xing (683-727 AD) devised a striking clock. In 1238 AD a water-powered alarm clock that announced the appointed hours of prayer was completed in 1235. User settable mechanical alarm clocks date back to at least the 15th century in Europe. 
     The need for alarm clocks in modern times is particularly driven by current lifestyles where almost everyone is required to attend work, classes or appointments at set times. Although it is perhaps beneficial in setting the body&#39;s circadian rhythms to awake naturally to the rising sun this is not an option for the vast majority of people who sleep in a closed environment with the windows shut and the shades drawn, and for whom waking times cannot vary with the seasons. The alarm clock, then, is a sometimes painful necessity of life. If two people are sleeping in the same bed or the same room there is the additional problem of the person for whom the alarm is not intended being waken by the alarm clock. For the second person, who often does not have the same schedule, the result is interrupted sleep with its attendant loss of sleep quality, or even the loss of the ability to return to sleep and the cutting short of the second person&#39;s natural requirement for sleep of a certain number of hours which varies between people both in the number of hours and the particular schedule they may keep. 
     Vibrating alarm clocks have been developed that at least in theory have the ability to wake one person without disturbing others in the same bed or room. Such vibrating alarm clocks may be placed under or in one sleeper&#39;s pillow or strapped to the arm. Nevertheless the vibrating alarm clock can produce sufficient sound to wake others if they are light sleepers and requires wearing an awkward wrist alarm, or placement of a vibrating alarm in or under a pillow in which case the vibration may not be sufficient to be reliable without producing a level of stimulus which will wake other sleeping companions, or will itself be unpleasant to the one awoken. 
     In recent times, taking advantage of advances in electronics, alarm clocks have been developed to awake a person at a particular stage in sleep by using sensor technology such as EEG electrodes or accelerometers calculated to avoid sleep inertia or grogginess following an abrupt awakening. Another approach to mediating grogginess is to employ a dawn simulator where a bedside lamp, or a light on the alarm clock itself is slowly increased in brightness over a set period of time which also is thought to be helpful in preventing seasonal affective disorder (SAD). These technologies do not directly address the problem of undesirable waking of roommates in the same room or a spouse sleeping in the same bed. 
     What is needed is an alarm clock which can combine light and sound stimulus that wakes only one person without disturbing others who are sleeping nearby. 
     SUMMARY OF THE INVENTION 
     The alarm clock of this invention employs a combination of directed light and sound which is mounted over the bed, and uses a thermal sensor to identify the location of each person sleeping in the bed and directs light and sound to only a single person. The alarm clock has a platform which is mechanically driven to scan the platform across the width of a bed. Mounted to the scanning platform is an infrared sensor which detects the surface thermal admittance, i.e. temperature, as the infrared scan sensor is scanned across the bed from side to side near the head of the bed, i.e. in the location where the bed occupants&#39; heads rest on the pillows. The output of the scan is a temperature profile with two thermal signature in the temperature profile which reliably indicate the position of each of the bed&#39;s occupants with respect to the rotation angle of the scan platform, in near real-time. Because for couples it is nearly universal that the same person sleeps on the same side of the bed night after night, the scan in addition to identifying the position of the bed occupants, also identifies each thermal signature with the person who normally sleeps on that side. 
     The a source of an alarm signal is also mounted to the scanning platform and consists of a narrow beam LED light and an array of ultrasonic speakers which form a parametric speaker which produces a narrow beam of sound which is heard only by the targeted sleeper. When the alarm signal is triggered for a set time, the scan platform points at the person designated to receive the alarm signal as identified by the infrared thermal signature associated with that person. The LED light is driven from a low value to a high value to produce a dawn simulator, following maximum brightness, the parametric speaker targets the wake-up audio which may consist of an alarm, the playing of music, or a recorded or synthesized message. 
     The alarm clock incorporates a wireless protocol so that it can be controlled by an app on a smart phone where the time of the alarm and nature and duration of the dawn light and audio alarm may be set. Shaking the smart phone is used as a snooze button. The infrared sensor or an additional optical sensor mounted on the scan platform is used to determine when the person to whom the alarm is directed is no longer present in the bed and the alarm is to be shut off. 
     Further objects, features and advantages of the invention will be apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded perspective view of an alarm clock and mounting bracket of this invention. 
         FIG. 2  is a perspective view from below with lowermost surfaces cut away, of the alarm clock of  FIG. 1 . 
         FIG. 3  is a inverted rear elevational view of the alarm clock of  FIG. 1 . 
         FIG. 4  is a schematic view of the sensors, actuator, and electronic components of the alarm clock of  FIG. 1   
         FIG. 5  is a graph of the output of the infrared sensor of the alarm clock of  FIG. 1  which shows thermal peaks indicating the positions of two people sleeping in a bed. 
         FIG. 6  is a pictorial view of the positioning and operation of the alarm clock of  FIG. 1 . 
         FIG. 7  is a flow diagram of the program used to operate the alarm clock of  FIG. 1   
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring more particularly to  FIGS. 1-7 , wherein like numbers refer to similar parts, an alarm clock  20  is shown in  FIG. 2 . The alarm clock has two parts: a base  22  and a platform  24  rotatably mounted on the base. As shown in  FIG. 6 , the base  22  is mounted by a backplate  27  which is shown in  FIG. 1 , to a wall  26  above a bed  28 . As shown in  FIG. 1 , the backplate  27  mounts to a wall bracket  30 . The wall bracket  30  is screwed to the wall and has protruding hooks  31  which extend through mounting holes  33  in the backplate  27  and engage the backplate so that the base is hung on the wall bracket. As shown in  FIGS. 1-3 , a stepping motor  32  is mounted to a case  23  which forms the exterior of the base  22 . The stepping motor  32  has a motor shaft  34  on which a gear  36  is mounted to rotate with the shaft along an arc. The motor  32  is mounted such that the gear  36  engages a partial gear  38  which snaps onto a platform drive shaft  40  integrally formed with the platform  24 . The drive shaft  40  is mounted to rotate in a sleeve  42  on the base  22 , the sleeve is integrally formed with the base such that operation of the stepper motor  32  can be used to drive the shaft of the platform  24  to oscillate the platform back and forth through an angle α along an arc over the bed  28  as shown in  FIG. 6 . For a king size bed with the alarm clock  20  mounted 5 feet above the mattress the angle α along the arc is about 65°. The stepper motor  32  can also be driven to a particular rotation angle along the arc to point the platform  24  towards a particular position between the sides  44  of the bed as indicated by the lines  48 . 
     As shown in  FIGS. 1 and 2 , a circuit board  46  is mounted to the platform  24  and has an upper face  50  on which are mounted electrical components represented schematically in  FIG. 4 , and a lower face  52  on which are mounted an infrared (IR) sensor  54  which is at least sensitive to infrared radiation produced by objects having a temperature between room temperature e.g., 20° C., and human body temperature e.g., 37° C. The lower face  52  also mounts a visual light sensor (VER)  55 , a light emitting diode (LED)  56  and an array of ultrasonic emitters  58  as shown in  FIGS. 1 and 2 . The lower face  52  of the circuit board  46  is arranged to point towards the bed  28  such that movement of the platform  24  points an aim line  60  perpendicular to the circuit board  46  so the aim line can be scanned or pointed along the angle α as shown in  FIG. 6 . 
     On the upper surface of the circuit board are mounted electrical components which are not shown in the figures except schematically in  FIG. 4 . These include a power handling chip or chipset  62  connected to rechargeable batteries  64 , e.g., 4 NiCD AAs, positioned on the right side of the base case  23 , by a power cable which passes through an opening  68  in the platform drive shaft  40  shown in  FIG. 3 . A LED driver chip or chipset  70  is connected to the LED  56  on the bottom surface of the board. A sensor input chip or chipset  72  is connected to the IR sensor  54 , and to the VER sensor  55 . The ultrasonic emitters  58  are connected to and driven by parametric speaker drivers chip or chipset  74 . 
     The stepper motor  32  is connected to a motor driver chip or chipset  75  which supplies power to the motor, back through the same opening  68  in the platform drive shaft  40 . A parametric speaker array  57  is disposed within the platform  24  and is comprised of multiple ultrasonic emitters  58  having ultrasonic horns  84 , one for each ultrasonic emitter. The motor  32  is driven to cause the platform  24  to scan across the bed  28  or to point the platform at a selected location  82  corresponding to a person who is targeted by the platform so that the LED light  56  and the parametric speaker array  57  is pointed at the targeted person. 
     A central processing unit (CPU)  86  contains a clock and memory which can store audio files which are sent to the speaker driver  74 . The CPU  86  communicates with a wireless protocol e.g., WIFI or Bluetooth, chip or chipset  76  which is also mounted on the upper face  50  of the circuit board  46 . The upper face  50  of the circuit board  46  also has two limit switches  78  which are engaged with angled surfaces  88  of an extension  90  of the upper surface  91  of the case  23  of the platform  24  and which extend downwardly on either side of the platform drive shaft  40  through an opening  87  in the platform  24 . When the drive shaft driven by the stepper motor  32  causes the platform  24  and the limit switches  78  to rotate past a selected angle, the nonmoving angled surfaces  88  engage against one or the other of the limit switches providing a signal to the CPU  86  for calibrating the position of the platform in correspondence with each step of the stepper motor. 
     Also mounted to the platform  24  are an off switch  79 , a reset switch  81 , a USB port  83 , and a DC voltage input connector  85 . The reset switch  81 , and the USB port  83  are connected to the CPU  86 . The DC voltage input connector  85  connects a recharger power supply  89  shown in  FIG. 6  to the batteries  64  and the on/off switch is connected to interrupt power from the batteries  64 . 
     As shown in  FIG. 1 , the platform  24  has a lower cover  92  having a lower flange  94  with a central opening  96  for the LED  56 , openings  98 ,  100  on either side of the central opening for the IR and VER sensors  54 ,  55 . Overlying the bottom of the lower cover  92 , except for the lower flange  94 , is an ultrasonic speaker grill  102 . Above the speaker grill  102  the ultrasonic horns  84  form part of an array housing  104  which is screwed to the circuit board lower face  52 . A sensor and LED cover  106  is positioned above the lower flange  94  and is screwed to the circuit board lower face  52 . The cover  106  covers the IR sensor  54  and the VER sensor  55  as well as the LED  56  and its reflector  108 , as shown in  FIGS. 1 and 2 . 
     The operation of the alarm clock  20  is described with respect to  FIGS. 5-7 . In  FIG. 6  the rotation of the platform  24  on the base  22  when it is mounted to the wall  26  is illustrated. When the alarm clock  20  is turned on by the switch  79  shown as Start in  FIG. 7 , the real-time clock (RTC) of the CPU is reset and synchronized to the time of day, which can be done by a user input from a smart phone application (app) which uploads the current time, or by querying a Network Time Protocol (NTP) server, or by an “Atomic” clock of the type with a built-in radio receiver tuned to The National Institute of Standards and Technology. Then, as part of the initialization, the stepper motor  32  is driven in one direction until it hits one of the limit switches  78 , and then driven in the other direction until it hits the other limit switch and the number of steps is counted so that the position of the platform  24  can be determined by the number of steps between the limit switch the stepper motor is commanded to make. Next, or after a reset (RST) either determined by the CPU  86  or commanded through the CPU by the reset switch  81 , the stored configuration including the alarm settings are read out of nonvolatile memory forming a part of the CPU or the CPU chipset. The CPU then enters a low power idle mode alternating with periodically checking to see if an alarm interrupt has fired. The alarm interrupt is created based on a timer, based on the clock of the CPU. The alarm interrupt specifies when the alarm is going to be initiated. When the timer reaches zero, the alarm interrupt sets a condition which, when detected, directs the program in the CPU to begin an alarm program. 
     If an alarm interrupt has fired, the alarm program causes the platform  24  to be driven to scan across the bed  28  and the output of the infrared sensor  54  is recorded and analyzed to detect thermal signatures such as the thermal peaks  110  in the output curve  112  derived from the scan as illustrated in  FIG. 5 . If a thermal signature is found, which is identified as a human body, the scan cycle stops; if not, the scanning is repeated, or, if the CPU detects an error condition, the alarm clock is reset. If the output curve  112  shows two human body thermal signatures, the one to whom the alarm signal should be directed is determined by which side of the bed was selected in setting the alarm. The alarm is initiated by stepping the platform  24  to the position of the selected person&#39;s thermal signature and the LED is driven with a slowly increasing power to simulate the sun rising, over a period of approximately 15 to 30 minutes to create a gentle awakening cycle that is thought to assist with regularity of the circadian rhythm and even prevent or cure seasonal affective disorder (SAD). 
     When the LED is at full brightness an audio alarm is created by the array of ultrasonic emitters  58  which are directed by the horns  84 . The alarm may consist of natural noises, a selected recording e.g., of music, or a more classical alarm sound. The ultrasonic output, because it is at a high frequency and has a much shorter wavelength than audible sound, is very directional. The output of the ultrasonic emitters is modulated in the audio range with an audio signal taken from the audio files stored and accessed by the CPU. The ultrasonic beam which is itself inaudible because its frequency, e.g. 40 kHz, is well above the human hearing range of about 20 Hz to 20 kHz has a power level sufficient to produce an audible sound of at least about 45 db sound pressure level when the audible range modulation signal in the ultrasound beam is extracted as the beam extends to the targeted person. The result is an audible sound which is highly localized and will not be heard by a person sleeping even quite closely to the targeted person as shown in  FIG. 6 . The alarm and the light are continued and increased in strength until the IR sensor  54  or the VER sensor  55  indicates that the targeted person has moved or preferably left the bed. 
     If the person being awoken does not wish to get up immediately the person can simply shake his or her smart phone and the app on the smart phone will communicate with the CPU through the wireless protocol chipset to turn off the alarm and reset it for period of time, e.g. 10 minutes, after which the alarm will be reinitiated. Typically on the reinitiated alarm, there will be a faster rise time of the intensity of the light and perhaps also the audible alarm. 
     It should be understood that the stepper motor  32  can be replaced by any type of actuator which can cause the scanning and pointing of the platform  24 , which may include, for example, a non-stepper motor in combination with a shaft encoder, or a piezoelectric motor or actuator. 
     It should also be understood that while light and sound beams may be most efficacious in waking a person, the particular type of beam(s) and how the beam(s) is/are generated could employ various beam generating devices now known or developed in the future. 
     It should be understood that, although smart phones are widely used by the general population and are therefore likely available for controlling the alarm clock  20 , other arrangements could be used to program the wake time, and control the operation of the alarm clock as, for example, a remote device like a television remote, or controls mounted on the alarm clock itself. 
     It should also be understood that the alarm clock  20  can be located at any position which allows scanning for the location of persons in a bed and aiming a beamed signal at one or more persons in the bed. 
     It is understood that the invention is not limited to the particular construction and arrangement of parts herein illustrated and described, but embraces all such modified forms thereof as come within the scope of the following claims.