Abstract:
An exercise monitoring pedometer for pets is directed toward measuring a pet&#39;s exercise over some, period of time, such as a day or week or month. The pet pedometer includes a solid state three-axis accelerometer, a signal processing unit, a CPU, a memory chip and a display with settable controls, and may include a voice recorder/player; or these functions may reside mainly on an application specific integrated circuit. The settable controls are directed toward providing a setting for pet stride size for conversion for walking and running, and for manual resetting. The pet pedometer auto-selects automatically for a pet&#39;s stride both a walking stride and a running stride. The present invention may also contain a recorder, typically a solid state recorder, which provide for a recording of the pet “owner&#39;s” voice, or selected music, so that the owner may record encouragement, etc., to his/her pet.

Description:
FIELD OF THE INVENTION 
   This invention relates to animal accessories, such as accessories for pets, in general. This invention relates to pet accessories for dogs. 
   This invention relates to pedometers where there are additional sources of the impact of a subject wearing the pedometer device other than that induced by the walking or running motion of the subject 
   BACKGROUND OF THE INVENTION 
   Pedometers, in general, have a long history, with continued patented improvements appearing from time-to-time. For example, “Pedometer with game mode”, (U.S. Pat. No. 6,302,789, Harada, et al., Oct. 16, 2001) is designed for getting children to get exercise by walking and running. 
   The “Exercise support instrument,” (U.S. Pat. No. 6,705,972, Takano, et al., Mar. 16, 2004), is designed to enhance a person&#39;s exercise program. A display for this device may contain a virtual animal, such as a dog; however, this is only a representation of a level of exercise achievement. 
   In “Pedometer for detecting vibrations in the motion direction,” (U.S. Pat. No. 6,836,524, Lee, Dec. 28, 2004), a vibration detector uses frequency filtering to filter out unwanted frequency vibrations of pace detector, while set to detect low level signals. 
   Takenaka (U.S. Pat. No. 6,254,513, Jul. 2, 2001) describes the use of two piezo-electric sensors suspended on levers, together with an angle of inclination sensor. 
   Lynch (U.S. Pat. No. 6,698,381, Mar. 2, 2004 describes the use of a sound chip and a speaker to have “Pet Accessories” emit prescribed sounds interactively, upon a pet completing an electrical circuit in pet accessory. 
   In the case of providing a measuring pedometer for a pet, such as a dog, there are additional considerations. First, one wishes to measure the exercise obtained by the pet while walking and running, but not by other motions which might otherwise register as a “step” on a pet pedometer. Second, pets, such as dogs, have different sizes, such as small, medium and large; it would be desirable to have one pet pedometer which can be set for different size pets. Third, it is desirable to have a lightweight, low cost, rugged pet pedometer. An additional desirable feature might include a recording of the pet “owner&#39;s” voice, to encourage or direct the pet, such as a dog, in its exercise activities. 
   SUMMARY OF THE INVENTION 
   The present invention, an exercise monitoring pedometer for pets, such as dogs, is directed toward measuring a pet&#39;s exercise over some, period of time, such as a day or week or month. 
   The pet pedometer comprises a solid state three-axis accelerometer, a signal processing unit, a CPU, a memory chip and a display with settable controls, and may comprise a voice recorder/player; or these functions may reside mainly on an application specific integrated circuit. 
   The settable controls are directed toward providing a setting for pet stride size for conversion for walking and running, and for manual resetting. The pet pedometer auto-selects automatically for a pet&#39;s stride both a walking stride and a running stride. The data may be retained for a longer period of time as a recallable data set, so that for a period of one day, the pet pedometer may reset itself after each day, for example at midnight, but have the previous n days recallable, where n may be 3, 5, 7, 14 or the previous weeks&#39; averages or monthly averages going back for a year which may be selected for display on a display unit, such an LCD display. 
   The present invention performs the functions of selecting a virtual vertical axis and selecting out, from the pet&#39;s actual walking and running, dominant frequencies applicable when the pet is walking and running. 
   The present invention may also contain a recorder, typically a solid state recorder, which provide for a recording of the pet “owner&#39;s” voice, or selected music, so that the owner may record exercise directions, encouragement, or a soothing reassurance to his/her pet, such as dog. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which: 
       FIG. 1   a  shows the pet pedometer with an attachable device shown as attached to a pet&#39;s collar. The pet is shown in outline and is not part of the invention; 
       FIG. 1   b  shows the pet pedometer integrated into a pet collar. The pet is shown in outline and is not part of the invention; 
       FIG. 1   c  shows the pet pedometer mounted on a pets front paw or front leg; 
       FIG. 2   a  shows a functional block diagram with exemplary functions; activities; 
       FIG. 2   b  shows a functional block diagram of the pet pedometer with exemplary functions; 
       FIG. 2   c  shows exemplary physical functions which the pet pedometer may perform; 
       FIG. 3   a , PRIOR ART, shows an exemplary single axis accelerometer; 
       FIG. 3   b , PRIOR ART, shows an exemplary micro-machined silicon accelerometer structure; 
       FIG. 3   c , PRIOR ART, shows an exemplary micro-machined silicon mass structure; 
       FIG. 4  shows analog signal output from the 3-axis accelerometer processed to yield dominant walking and running frequencies; and 
       FIG. 5  shows an application specific integrated circuit encompassing major functional areas for the pet pedometer. 
   

   DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
   The following description is of preferred embodiments presently contemplated for carrying out the invention. This description is not to be taken in a limiting sense, but is merely made for the purpose of describing the general principles of the invention. 
     FIG. 1   a  shows a preferred embodiment of the pet pedometer in its case  101  with a display  102  and settable controls  103 . The pet pedometer case  101  is disposed to receive an attaching device  104  which allows for attaching the pet pedometer to a pet collar  105 . The pet is shown in outline and is not part of the invention. 
     FIG. 1   b  shows a preferred embodiment of the pet pedometer integrated into a pet collar  151 , where the display  152  and settable controls  153  may be on the “top” of a pet collar  151  with a microphone/speaker unit  156  and the remainder of the pet pedometer, including accelerometer unit  157 , sensor, digital signal processing/CPU unit  158 , memory unit  159 , remainder of control unit  160  and sound recording unit  161 , are electrically connected by wires  162  embedded into the pet collar  151 . The pet is shown in outline and is not part of the invention. 
     FIG. 1   c  shows a preferred embodiment of the pet pedometer placed on the paw or front leg of the pet, such as a dog. This embodiment of the pet pedometer is shown in its case  101  together with its display  102  and settable controls  103 . Attaching means  171 , such as elastic bands, for example, act to secure the pet pedometer  101  in place on a pet&#39;s leg or on top of the pet&#39;s paw. 
     FIG. 2   a  is a block flow diagram for an embodiment of the pet pedometer. The sensor part of the pedometer is a three-axis accelerometer  201 . The analog output from the three-axis accelerometer  201  is amplified and conditioned by the signal amplifier and signal conditioner  202 . 
   The signal conditioner  202  also performs analog to digital (A/D) conversion. The digitized output from the signal conditioner/amplifier/digitizer  202  is input to a digital processor (CPU/controller)  203  which processes the digitized data from the 3-axes accelerometer  201 . 
   The CPU  203  performs fast Fourier transforms (FFT&#39;s), in one embodiment, on the three-axes accelerometer  201  output data, and ranks the largest amplitude components, while a pet is walking, and then when a pet is running. By ranking the amplitudes, a largest amplitude may be selected out as the amplitude to be associated with walking and with running. For the case where the pet may be rolling around, then the CPU  203  detects additionally sporadic much higher or much lower frequencies from the accelerometer, so that no record of a step by the pet is made. Similarly, when the “walking” frequency is detected, a stride length is associated with that “walking” step. When a “running” frequency is detected, a stride length is associated with that “running” step. Thus an auto-selection, independent of any a priori knowledge of pet size, is performed by a preferred embodiment of the pet pedometer. 
   The Display Functions  204  includes automatic functions such as displaying the up-to-present number of steps, or distance, or both, traveled since last reset; and may include automatic resetting of the display to a zero display every 24 hours, at midnight, for example. In an embodiment, display functions  204  also include manual functions  205 , such as a manually controlled review of the daily steps/distance from the previous 7 or 14 days. Similarly an embodiment provides for a manual review of monthly averages of the past 12 months, month-by-month. The monthly averages are computed automatically and are stored for display; a manual operation displays these automatically obtained monthly averages. 
   Manual control functions  205 , in an embodiment, as examples, include setting up of the pedometer display, zeroing the pedometer display, reviewing previously acquired data, setting date and time, manually operating a recording of an owner&#39;s, or other&#39;s voice, and setting playback options for the owner&#39;s voice. Other manual functions are incorporated into other embodiments of the invention. The manual functions mentioned above are exemplary and may be supplemented. 
   Memory Functions  206  include string fixed parameters, storing acquired parameters and storing voice recordings of the pet owner&#39;s, or others, voice, or music. 
   Voice Functions  221 , in an embodiment, include digital recording  222 , utilizing a recording transducer function  224 , a playback function utilizing a playback transducer function  FIG. 225 . In one embodiment, the voice function includes an analog to digital conversion function  221  for recording and a digital to analog conversion  221  for playback. In another embodiment, the voice functions  221  are carried out as part of the digital [processing functions  203 , as indicated by the heavy dit-dash double ended arrow between voice functions  221  and digital processing/control functions. Similarly, in an embodiment, the voice recording storage voice function is carried out as part of the memory function  206 , as indicated by the heavy dit-dash double ended arrow between voice functions  221  and memory functions  206 . 
     FIG. 2   b  represents an activity flow diagram for an embodiment of the pet pedometer. The pet pedometer activity is activated by a motion induced into the pet pedometer by the walking or running  251  of the pet. The pet and its motions are not part of the pet pedometer invention; the pet&#39;s motion is detected by the first part of the invention, viz., a motion sensor which performs the motion sensing activity  252 . The motion sensed by the motion sensing activity  252  is subjected to frequency analysis  253 . A select main frequency activity is carried out on the motion-induced frequencies along three orthogonal axes, denoted x, y, and z. The dominant amplitude along the z-axis is determined by a comparison of the amplitudes associated with each frequency, as analyzed by the frequency analysis activity. 
   In an embodiment of the pet pedometer, the frequency analysis  253  is developed by utilizing a fast Fourier transform (FFT), either by a general purpose central processing unit (CPU), or by a more specialized area of an application specific integrated circuit (ASIC). 
   Once a dominant frequency for walking and running is auto-selected for the z-axis, the amplitudes corresponding to this dominant frequency are examined on the x-axis and the y-axis, where x-, y-, and z-axis form an orthogonal rectangular coordinate system. Utilizing the dominant frequency as determined by the z-axis Fourier analysis, a resultant vector at this dominant frequency is formed from the amplitudes on the x, y, and z-axes. This is the virtual vertical, for an embodiment of the pet pedometer. This is a vertical which accounts for any shift in the true virtual z-axis from the orientation of the z-axis in the 3-axis accelerometer. This virtual z-axis is the axis for accounting of steps, regardless of the actual orientation of the pet pedometer and so allowance is made if the actual pedometer is not in exact alignment, with z in the opposite direction to the Earth&#39;s gravitational field and the x and y axes are not in exact alignment in a plane perpendicular to the direction of the Earth&#39;s gravitational field. 
   The dominant or main frequency, as well as the direction of the virtual z-axis, relative to the three axes of the accelerometer, is stored by the store main frequency/main axis activity  256 . 
   The accelerometer switches between a “walking mode” and a “running mode”, depending upon which dominant frequency is detected. The distance traversed is then calculated by the number of steps times the walking stride length or the running stride length, depending upon the dominant mode detected. 
   After the store main frequency/main axis occurs, the motion sensor output is directed  265  to record number of steps  257  and to display the current number of steps  258 . 
   The step display includes steps and distance in an embodiment of the pet pedometer. The number of steps/distance is recorded cumulatively  259  with conversion of steps to distance  263 , while an auto-reset  261  or manual control  261  activity resets the cumulative counter, as desired. In an embodiment of the pet pedometer, steps/distances are recorded by day for two weeks  260 . A manual scroll control  262  allows for scrolling through the current two-week running period. An auto-reset activity  264  deletes the trailing (oldest) day after 14 days of step/distance are accumulated. In an embodiment of the pet pedometer, a monthly steps/distance average is kept for a running 12 months, and a manual scroll control gives access to these saved monthly averages. 
     FIG. 2   c  shows the analog amplification  282  of the three analog accelerometer signals generated by the three-axes accelerometer. These signals are amplified  282  and converted to digital signals  283  by an analog to digital converter (A/D chip or A/D region on an ASIC). The fast Fourier transform  284  of the output from the digitized signal  283  is used to isolate the dominant frequency  285  in the z-direction (vertical) by ranking frequency amplitudes and selecting the largest or dominant or main frequency  285  for a walking pet and a running pet. The x- and y-main frequencies  285  are also determined so as to prevent a step being recorded if these x- and y-frequencies differ too much from the x- and y-main frequencies. 
   A review of how an accelerometer works indicates the feasibility of achieving a small, on chip, CMOS process, or silicon micro-machined accelerometer 
   The applied acceleration of the casing causes the mass to move, and this motion can be used to determine the magnitude of the acceleration. 
   Examining  FIG. 3   a , PRIOR ART, let x  301  be the displacement of the mass m  302  relative to the casing  303 . When the casing  303  has acceleration a, the equation of motion for the mass  302  is
 
 m{umlaut over (x)}+β{dot over (x)}+kx=−ma,  
 
   The behavior of this dynamic system is determined by two parameters: the natural frequency ω n =√{square root over (k/m)}, and damping ratio ζ=β/√{square root over (4mk)}. Using these parameters, the equation of motion becomes
 
 {umlaut over (x)}+ 2ζω n   {dot over (x)}+ω   n   2   x=−a.  
 
   The solution to this equation consists of a transient response which depends on the specific initial conditions, and a steady-state response, which is independent of initial conditions. If the response of the system is sufficiently fast, it is reasonable to ignore the transient response. Focusing on the steady state response, we introduce two important performance parameters as follows. 
   Minimum detectable acceleration. Let the applied acceleration be a constant. The steady state response is then x=a/ω n   2 . In other words, the steady-state net stretch or compression of the spring is directly proportional to the applied acceleration. Suppose that the minimum measurable spring deflection is x min , then the minimum detectable acceleration of the accelerometer is given by
 
 a   min   =x   min ω n   2 .
 
   Bandwidth. Let the applied acceleration be a sinusoid with circular frequency ω, i.e., a=a 0  cos(ωt). The steady-state deflection of the spring is of the form x=x 0  cos(ωt+φ). The deflection magnitude x 0  is related to the magnitude of the applied acceleration a 0  by 
   
     
       
         
           
             
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   As indicated by the notation, x 0  depends on the driving frequency ω. In particular, x 0  becomes diminishingly small when ω is sufficiently large, and the accelerometer will cease to be useful for accelerations at such a frequency. In practice, the bandwith within which the accelerometer is useful is given by the cutoff frequency ω c . This frequency is defined by the equation x 0  (ω c )/x 0 (0)=1/√{square root over (2)}, and is given by
 
ω c =γω n  
 
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   As an example, we consider a micro accelerometer structure. The accelerometer has a configuration shown in  FIG. 3   b , PRIOR ART, (top and cross-sectional views). Using micromachining technology, the silicon mass  351  is shaped like a truncated pyramid  375 , as shown in  FIG. 3   c , PRIOR ART. Note that the mass  375  is shown upside down for convenience in visualization. 
   By the nature of the micromachining process used, the edge lengths of the two horizontal surfaces of the silicon mass are a 1  and a 2 =a 1 −t/√{square root over (2)}, where t is the thickness of the mass. The mass can be calculated from the formula 
   
     
       
         
           
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   where ρ=2300 kg/m 3  is the density of silicon. As shown in  FIG. 2   b , the mass  351  is suspended by eight beams  352 , which are also fabricated from silicon. Integrated strain gauges  353  are fabricated on the surface of each beam (at the end of the beam where strain due to bending achieves a maximum), and are used to measure the deflection of the beam. The damping in the sensor mainly arises from squeeze-film effects in the air gap between the silicon mass and the bottom encapsulation. 
   We can assess a micro accelerometer performance. As an example only, an accelerometer is to be designed to satisfy the following specifications: (1) the minimum detectable acceleration should be smaller than 0.02 g, where g is gravitational acceleration. We assume that the minimum measurable strain of the silicon beams allowed by the strain gauges is ε min =5×10 −7 ; and (2) the bandwidth, given by the cutoff frequency for sinusoidal accelerations, should be greater than 4 kHz. Thus, the damping ratio should be in the range 0.6≦ζ≦1.1 so that the transient response of the accelerometer has desired characteristics. 
   We can choose, as an example only, some micro accelerometer design parameters which involve the selection of the following parameters. The dimensions of the silicon mass (a 1 ), the dimensions of the silicon beams (l, b, and h), and the depth (d) of the air gap between the silicon mass and the bottom encapsulation. These design parameters are to be chosen from the following practical ranges allowed by micromachining technology: 
   1 mm≦a 1 ≦5 mm, 300 μm≦l≦600 μm, 100 μm≦b≦300 μm, 2 μm≦h≦10 μm, 5 μm≦d≦40 μm. Note that the thickness t of the silicon mass is given by that of the silicon wafer (525 μm) from which the accelerometer is fabricated. 
     FIG. 4  shows an exemplary pet pedometer, in an embodiment of the pet pedometer, composed of a three-axes accelerometer unit  401 , with amplifier chips  402 , feeding into A/D chips  403 , which in turn feeds a CPU  404  with both a read only memory ROM  405  and a rewritable memory  406 , such as a RAM, or an EEPROM, or other solid state rewritable memory  406 . A battery power source is present but not shown. 
     FIG. 5  shows an analogous version of a pet pedometer, in an embodiment of the pet pedometer, as different functional areas on an ASIC chip which is specifically designed to express most of the pet pedometer functions on a single application specific chip (ASIC). In  FIG. 5 , the x-axis  501 , y-axis  502 , and z-axis  503  accelerometers are shown as CMOS accelerometers, with signal conditioning  504 , which includes amplification and digitization, a CPU/control area  505 , together with a memory area  506 , voice functions  507  (including voice storage and playback) and an input/output area (I/O)  508 . A battery power source is present but not shown. 
   Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means and methods. The following description is of the best mode presently contemplated for carrying out the invention. This description is not to be taken in a limiting sense, but is merely made for the purpose of describing the general principles of and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention.