U.S. patent application number 09/756647 was filed with the patent office on 2001-09-06 for pedometer.
Invention is credited to Pyles, Nathan.
Application Number | 20010019598 09/756647 |
Document ID | / |
Family ID | 22665580 |
Filed Date | 2001-09-06 |
United States Patent
Application |
20010019598 |
Kind Code |
A1 |
Pyles, Nathan |
September 6, 2001 |
Pedometer
Abstract
The pedometer having improved accuracy by calculating actual
stride lengths of a user based on relative stride rates. The
pedometer includes a waist or leg mounted stride counter, a
transmitter for transmitting data to a wrist-mounted display unit,
and a data processor for calculating necessary base units and
actual stride rates and lengths. The pedometer can also interact
with a heart monitoring device.
Inventors: |
Pyles, Nathan; (Lake Mills,
WS) |
Correspondence
Address: |
LATHROP & CLARK LLP
740 REGENT STREET SUITE 400
P.O. BOX 1507
MADISON
WI
537011507
|
Family ID: |
22665580 |
Appl. No.: |
09/756647 |
Filed: |
January 4, 2001 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
09756647 |
Jan 4, 2001 |
|
|
|
09181738 |
Oct 28, 1998 |
|
|
|
6175608 |
|
|
|
|
Current U.S.
Class: |
377/5 |
Current CPC
Class: |
G01C 22/006
20130101 |
Class at
Publication: |
377/5 |
International
Class: |
A63F 001/18 |
Claims
1. An exercise monitoring device comprising: a strap for releasably
securing the exercise monitoring device to a user; a step counter
joined to the strap; and a heart rate monitor joined to the
strap.
2. The exercise monitoring device of claim 1, and further
comprising: a data processor programmed to calculate a distance
traveled by multiplying a number of steps counted by the step
counter by a stride length that varies according to a rate at which
steps are counted.
3. The exercise monitoring device of claim 1, and further
comprising: a data processor programmed to calculate a distance
traveled by multiplying a number of steps counted by the step
counter by a stride length that varies in accordance with a stride
rate, wherein the stride length is determined with reference to a
plurality of calibrations that each calculate a stride length as a
function of a known stride rate.
4. The exercise monitoring device of claim 3, wherein the data
processor is further programmed to recalibrate the stride length as
a function of a subsequently calculted and known stride rate.
5. The exercise monitoring device of claim 4, wherein the data
processor is further programmed to recalibrate the stride length by
calculating an average stride length from the calibration stride
length and the recalibration stride length.
6. The pedometer of claim 1, and further comprising: a data
processor programmed to calculate a distance traveled by
multiplying the number of steps counted by the step counter by a
stride length that varies according to a rate at which steps are
counted, and further programmed to derive the stride length from a
range of stride lengths calculated from a range of corresponding
stride rates calculated from a plurality of calibration samples
7. A pedometer comprising: a step counter; a transmitter in
communication with the step counter to generate a step count signal
corresponding to each step and transmit the step count singal; a
receiver mountable on a user body portion to receive the step count
signal transmitted from the transmitter; and a data processor
programmed to calculate a distance traveled by multiplying a number
of steps counted by a stride length that varies according to a rate
at which steps are taken, and further programmed to derive an
actual stride length from a range of stride lengths calculated from
a range of corresponding stride rates.
8. The pedometer of claim 7, wherein the data processor is further
programmed to: use the range of stride rates to create a
corresponding range of stride lengths and compare an actual stride
rate to the range of stride rates to derive a corresponding actual
stride length.
9. The pedometer of claim 8, wherein the data processor is further
programmed to: interpolate between and extrapolate from the ranges
of stride rates and stride lengths to calculate a plurality of
additional corresponding stride rates and stride lengths.
Description
[0001] This application is a continuation of application Ser. No.
09/181,738, filed Oct. 28, 1998, the disclosure of which is
incorporated by reference herein.
FIELD AND BACKGROUND OF THE INVENTION
[0002] The present invention relates generally to pedometers having
a waist mounted stride-counting device and transmitter, and a
wrist-mounted receiver and display. The invention also relates to a
distance calculation device that calculates a distance walked or
run based on an algorithm that converts a base stride length and a
base stride rate to an actual stride length for use in calculating
the distance traveled.
[0003] Pedometers are known which include devices or algorithms for
determining the distance a person travels on foot. For example,
U.S. Pat. No. 4,371,945 discloses an electronic pedometer that
calculates distance by electronically measuring the length of each
stride taken by a user. Stride length is measured by ultrasonic
waves generated by an ultrasonic module strapped to one leg and an
ultrasonic detector worn on the other leg. A program compensates
for a variety of measurement errors and the results are displayed
on a wrist-mounted display after being transmitted by VHF waves
from the leg to the wrist.
[0004] U.S. Pat. No. 4,771,394 discloses a computer shoe with a
heel-mounted electronic device with an inertia footstrike counter,
a timer, a sound generating device, a battery, and a gate array for
counting time and footstrikes to calculate distance and running
time as a function of stride time. Although recognizing the
important relationship of stride length and foot speed, the shoe in
this patent requires data from at least 15 test runs or walks and
the data must be user-entered in pairs of footstrikes and elapsed
time to cover a predetermined distance. Further, user adjustments
of time must be performed to accommodate start and stop times, and
the number of counted footstrikes is increased one percent to
overcome inherent errors in the inertia step counter. The
shoe-mounted device is subject to damage from impact, dirt, and
water, and requires a stay-at-home computer with which to
interface. There is no means disclosed to transmit data to a
wrist-mounted display device or an "on-board" computing device that
provides "real time" data to a runner.
[0005] U.S. Pat. No. 4,855,942 discloses a pedometer and calorie
measuring device that includes a wrist-mounted step counter and a
fixed stride length to calculate distance traveled. Wrist-mounted
step counters are known to be inaccurate because they assume a step
for every arm movement. Even with error correction, such a device
will provide less accurate step counts than a leg or waist-mounted
counter. Further, fixed stride lengths do not take into account the
fact that stride length varies with rate of movement.
[0006] U.S. Pat. No. 5,117,444 discloses a pedometer and
calibration method with two calibration modes. First, a user
travels a predetermined "half-distance" for the device to count and
store the number of strides in that distance. Next, the user
travels a second distance with the step counter comparing actual
steps to the steps in memory and a current trip memory are
incremented by a tenth of a "whole unit" distance. There is no
correlation between stride length and stride rate which requires
the user to re-calibrate the device when walking as opposed to
running.
[0007] U.S. Pat. No. 5,475,725 discloses a pulse meter with
pedometer function to determine pace and pulse rate of a user. The
meter uses pulse wave base data compared to actual pulse wave data
rates.
[0008] U.S. Pat. No. 5,476,427 discloses a pace display device
utilizing a base rate for traveling pre-set distances in successive
trails. The device calculates step counts and rates, and compares
actual step count rates to display data to a user for comparison of
present running rates to previous rates.
[0009] Thus, there is a need for a simple, but highly accurate,
pedometer that displays distance traveled, pace, speed, heart rate,
and other important information on an easily read wrist-mounted
device.
SUMMARY OF THE INVENTION
[0010] The present invention overcomes problems and shortcomings in
the prior art by providing a device that includes a waist, chest,
or leg-mounted stride counting device, a transmitter, and a
wrist-mounted receiver/display device that provides highly accurate
travel distances and other information. The device includes a
computer that stores base stride length and rate data from
traveling a predetermined distance and compares that to actual
stride rate data to calculate actual distance traveled, speed, and
pace. The invention recognizes the interdependency of stride length
and stride rate and uses that relationship to provide superior
distance-calculating accuracy.
[0011] The invention also provides for improved display of relevant
data on a wrist-mounted display that receives digital signals from
devices worn on other body parts such as legs, waist, and chest.
Transmitters that can send coded signals are desirable because they
will not interfere with similar devices worn by other users in the
vicinity.
[0012] The accuracy of the device is enhanced by the use of an
algorithm that adjusts a base stride length based on actual stride
rates. The algorithm is defined as: Actual Stride Length=Base
Stride Length+Base Stride Length*(((Actual Stride Rate-Base Stride
Rate) N)/Base Stride Rate); where N is either an average value or a
derived value from a plurality of samples.
[0013] The invention also includes a method for calculating an
actual stride length including steps of: timing a first user run of
a predetermined distance; counting the total number of strides in
the user first run; dividing the first run distance by the stride
count to obtain a base stride length; dividing the stride count by
the first run time to obtain a base stride rate; counting strides
during a user's second run to obtain an actual stride rate;
calculating the actual stride length using the formula: Actual
Stride Length=Base Stride Length+Base Stride Length*(((Actual
Stride Rate-Base Stride Rate )N)/Base Stride Rate); wherein N is an
average value or a derived value.
[0014] The average value method can be refined by comparing Base
Stride Rate to Actual Stride Rate to determine a percentage
difference; and using N=1 when the Actual Stride Rate<Base
Stride Rate*1.02 and using N=3 when Actual Stride Rate>Base
Stride Rate*1.02. A preferred embodiment uses a plurality of sample
runs over known distances to derive an accurate N value for each
individual.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a schematic diagram of a pedometer in accordance
with the present invention.
DETAILED DESCRIPTION OF THE DRAWINGS
[0016] As illustrated in FIG. 1, the present invention is directed
to an improved pedometer 20 including: a waist, chest, or leg
mounted stride counter 24, and a wrist or waist mounted display
unit 26. An optional chest-mounted heart monitor 28 can be
included. All of the device components are mounted in suitable
housings. The pedometer 20 includes a data processor 30 that is
mounted in the same housing as either the step counter 24 or the
display unit 26.
[0017] The step counter 24 is an inertia device that counts the
number of steps a user takes. The number of steps is transmitted to
a data archive 32 either directly or via a transmitter 34. The data
archive 32 is mounted in the housing with the step counter 24 or
the display 26.
[0018] The transmitter 34 is mounted in the step counter housing
and is preferably an Rf telemetric signal transmitter with a 30
inches to 36 inches transmission range. Alternately, the
transmitter is a wireless or wired digital transmitter with a
coding function to limit or eliminate interference with other
similar devices. The wireless transmission range is set between 30
inches and 36 inches to provide adequate range to transmit signals
from a user's waist to wrist, but not so far as to cause
interference with other Rf or digital devices in the vicinity.
[0019] The transmitter 34 transmits either raw data or calculated
distances, pace, etc. to a wrist-mounted display unit receiver 40.
The receiver 40 relays a raw data signal to the data processor 30
or a calculated data signal directly to the display panel 42, such
as an LCD or LED.
[0020] Similarly, the heart rate monitor 28 includes a transmitter
44 that transmits heart rate data to the display unit 26. The heart
monitor transmitter 44 can transmit at the same or a different
frequency as the stride counter 24, and to the same or a different
receiver in the display unit 26. The heart rate transmitter 44 is
preferably Rf, but can be digital for the reasons stated above. The
range of the heart rate transmitter 44 should also be between 30
inches and 36 inches to ensure effective communication with the
receiver while limiting outside interference.
[0021] The data processor 30 can also include a programmable logic
controller, a personal computer, a programmable read-only memory,
or other suitable processor. The data processor 30 includes a data
archive 32 to store historic data on stride length and pace to be
used in an algorithm for calculating actual distances, speed, and
rate for real-time conversion of data to useful information for a
user.
[0022] The data processor 30 can also include closed loop or fuzzy
logic programming to continually or periodically replace the base
stride rate and length with recently calculated stride rates and
lengths so that long term conditioning trends are accommodated in
the base stride archive. Incorporating trend capabilities may
further enhance accuracy of the distance and pace calculations.
[0023] The display unit 26 also includes an operator interface 46
such as a key pad, button, knob, etc. that enables the user to
start and stop a clock 48 (or stop watch) and activate various use
modes within the pedometer, such as a sampling mode and operation
mode.
[0024] One option for using the pedometer 20, requires the user to
operate a "sampling mode" and begin walking or running a
predetermined distance such as a mile or 1600 meters, preferably on
a running track of a known size. Upon completion of the distance, a
stop button on the operator interface 46 is pushed. The data
processor 30 is programmed to then divide the distance by the
number of strides counted to calculate an average stride length.
This value is stored in the data archive 32 as the "Base Stride
Length."
[0025] Also, the data processor 30 is programmed to divide the
number of strides by the time of the run or walk as measured by the
clock 48 to arrive at a "Base Stride Rate."
[0026] The data processor 30 preferably includes programming that
queries the user about the distance to be run during the sampling
mode. By providing options or enabling the use of any distance
during the sampling mode, the pedometer 20 provides maximum
flexibility for use by people of various physical conditions, or
having access to courses of different known distances. Thus, a user
may be queried to input a distance to be used in the sampling mode
and then be given a list of options such as 400 meters, 440 yards,
1600 meters, or one mile, or be asked to simply input any distance
known to the user that will be traveled during the sampling
mode.
[0027] The present invention makes full use of the relationship
between a faster rate of travel and longer stride lengths. In other
words, the faster a user is moving, the longer will be the stride
length. Over the course of the run or walk, the user's step rate
and, therefore, stride length will change and the user will cover
more ground when moving fast and less ground when moving slow.
[0028] Clearly, using a fixed average stride length in calculating
distance traveled will result in errors using prior pedometers.
This is particularly true if a user changes pace, or improves
conditioning and speed to the point where the average stride length
over a given run increases dramatically. The error compensators in
prior devices do not adjust for changes in pace. With the old
devices, a user needed to re-calibrate periodically to be close to
getting an accurate reading, and could not change pace during a
workout without decreasing accuracy.
[0029] To make the correction, the user activates a "Use Mode" in
which the data processor 30 calculates an Actual Stride Rate based
on data from the stride counter 24 and the clock 48. For example,
an Actual Stride Rate can be calculated every five seconds without
the user doing more than activating the "Use Mode" button, while
all the calculations are performed by the data processor
automatically. The percentage change between the Actual Stride Rate
and the Base Stride Rate is then computed by the data processor 30
to determine an Actual Stride Length. Again, if the Actual Stride
Rate is greater than the Base Stride Rate, the Actual Stride Length
is longer than the Base Stride Length. If the Actual Steps Per
Second is lower than the Base Steps Per Second, the Actual Stride
Length is shorter than the Base Stride Length. The algorithm below
provides a means for comparing the Actual and Base Stride rates to
arrive at an accurate Actual Stride Length.
[0030] First, a comparison between the Actual Stride Rate and the
Base Stride Rate is made to determine whether Actual Stride Rate is
less than or equal to Base Stride Rate multiplied by 1.02. Stride
Length is calculated by:
Actual Stride Length=Base Stride Length+Base Stride
Length*(((Actual Stride Rate-Base Stride Rate)N)/Base Stride
Rate)
[0031] Where: N=1 when Actual Stride Rate is less than or equal to
Base Stride Rate multiplied by 1.02, and N=3 when Actual Stride
Rate is greater than Base Stride Rate multiplied by 1.02, although
other N values in the range of one to three can be used.
[0032] The above algorithm is accurate for heel to toe activities
such as walking or jogging, but is less accurate for sprinting (toe
only).
[0033] A third method of calculating actual stride length uses
three separate run or walk samples at three different paces. This
is the most accurate option. With this method, the N values are
unique for each individual. By deriving an N value for each
individual, this value more accurately reflects the actual change
in stride length with a change in pace. After a proper warmup, the
user completes a sample run or walk on the track at a normal pace.
This first sample S1, will establish the Base Stride and the Base
Steps Per Second.
[0034] S1 Sample:
S1 Stride=Base Stride=Distance/Number of Steps
S1 Steps Per Second or S1 Steps Per Second=Base Steps Per
Second=Number of Steps Per Second
[0035] Following completion of the first run or walk at normal
pace, the user runs or walks the same course and the same distance
at a faster run or walking pace, but not a sprinting pace. The user
should not run on his toes, but maintain the normal heel to toe
jogging style. This is the S2 sample. The purpose of the S2 sample
is to calculate an N2 value for each individual which reflects the
effect an increase in Steps Per Second has on this individual's
stride length. Some individual's steps will lengthen more than
others as Steps Per Second increases, and by finding the value for
N2, this relative increase can be quantified for a more accurate
and customized algorithm for each individual.
[0036] S2 Sample:
[0037] To find the N2 value, which will be used by the algorithm
when Actual Steps Per Second>Base Steps Per Second
N2=((S2 Stride*S1 Steps Per Second)-(S1 Stride*S1 Steps Per
Second))/(S1 Stride (S2 Steps Per Second-S1 Steps Per Second))
[0038] This value can be calculated since the distance is known,
and both a Fast Stride Length (S2 Stride) and a Fast Steps Per
Second (S2 Steps Per Second) can be calculated from the second
sample.
[0039] Following completion of the fast run or walk, the user runs
the same course and the same distance at a slower than normal run
or walking pace. This pace cannot exceed the first sample pace.
This is the S3 sample. The purpose of the S3 sample is to calculate
an N3 value for each individual which reflects the effect a
decrease in Steps Per Second has on this individual's stride
length. Some individual's steps will shorten more than others as
Steps Per Second decreases, and by finding the value for N3, this
relative decrease can be quantified for a more accurate and
customized algorithm for each individual.
[0040] S3 Sample:
[0041] To find the N3 value, which will be used by the algorithm
when Actual Steps Per Second<Base Steps Per Second.
N3=((S3 Stride*S1 Steps Per Second)-(S1 Stride*S1 Steps Per
Second))/(S1 Stride (S2 Steps Per Second-S1 Steps Per Second))
[0042] This value can be calculated since the distance is known and
both a "Slow" Stride Length (S3 Stride) and a "Slow" Steps Per
Second (S3 Steps Per Second) can be calculated from the third
sample.
[0043] Once these three samples are completed and the information
automatically calculated and stored in the data processor 30, then
the following formula can be used for the most accurate
measurements of speed and distance.
[0044] If: Actual Steps Per Second is less than or equal to Base
Steps Per Second
[0045] Then:
Stride Length=Base Stride+Base Stride*(((Actual Steps Per
Second-Base Steps Per Second)N)/Base Steps Per Second)
And N=N3 (Stored Value)
[0046] If: Actual Steps Per Second>Base Steps Per Second
[0047] Then:
Stride Length=Base Stride+Base Stride*(((Actual Steps Per
Second-Base Steps Per Second)N)/Base Steps Per Second)
And N=N2 (Stored Value)
[0048] This third option for calculating stride length, and
subsequently distance, speed, and pace, is a far more accurate
method than a fixed stride length pedometer. This device and method
are also practical, convenient, and has a relatively low
manufacturing cost. If an individual's running or walking style is
progressing with training and practice (as seen by significantly
improved times), then it may be beneficial for them to recalibrate
their device by repeating the three samples every 3 to 6 months. If
there are no significant improvements in time, then recalibration
is not necessary.
[0049] It is noted that any single stride length or pace discussed
above can in fact be an average of a plurality of stride lengths or
rates from test runs to further refine accuracy in the calculations
of actual stride data.
[0050] Other variations on this device could also incorporate an
altimeter which measures changes in elevation. The stride length
could then be adjusted (shortened) when elevation is increasing,
and lengthened when elevation is decreasing. This adjustment could
be done with an average value, as we used in setting option 2, or
with a derived value by running or walking over a known distance on
a hilly course. This device can use two batteries so that the
calibration data is not lost when the batteries are replaced one at
a time.
[0051] Once the actual stride length is calculated for a given
period of time, the value can be multiplied by the number of
strides in that period to obtain a total distance for that period
to be stored in a data archive file for that particular walk or run
and added to other actual stride lengths or distances for other
periods in which stride length was calculated. When the run or walk
is completed, the user engages the operator interface 46 to
indicate that a total distance is to be displayed on the display
unit. Preferably, there is continual display of the distance
traveled.
[0052] As a result of accurately calculating distance traveled, the
pedometer 20 also has the capability of calculating speed in miles
per hour, for example or pace in minutes per mile, including
average speed and pace over the course of that particular walk or
run. Further, the pedometer 20 can include a port for coupling to a
separate personal computer or computing device to create larger
training histories, trends, etc.
[0053] Additional features can include stop watches, day, date and
time displays, as well as, heart rate displays as discussed above.
Also, it will be understood that all distances and time periods
used above can be varied in length and units of measure (English,
metric, seconds, minutes, hours, etc.).
[0054] The foregoing detailed description is provided for clearness
of understanding only and no unnecessary limitations therefrom
should be read into the following claims.
* * * * *