Opposing accelerometers for a heart rate monitor
A heart rate monitor ( 40 ) for detecting a pulse of a person ( 10 ) employs a platform ( 43 ), a plurality of multi-axis accelerometers ( 41 R, 41 L) and a pulse detector ( 44 ). The multi-axis accelerometers ( 41 R, 41 L) are adjoined to the platform ( 43 ) to generate differential mode signals (A ZR , A ZL ) indicative of a sensing by the accelerometers ( 41 ) of physiological motion ( 12 ) of the person ( 10 ) relative to acceleration sensing axes ( 42 R, 42 L) and to generate common mode signals (A XR , A XL , A YR , A YL ) indicative of a sensing by the accelerometers ( 41 R, 41 L) of extraneous motion by the person ( 10 ) relative to the acceleration sensing axes ( 42 R, 42 L). The pulse detector ( 44 ) is operably connected to the multi-axis accelerometers ( 41 R, 41 L) to generate a pulse signal (PS)as a function of a vertical alignment of the acceleration sensing axes ( 42 R, 42 L) combining the differential mode signals (A ZR , A ZL ) and cancelling the common mode signals (A XR , A XL , A YR , A YL ).
1. A method for a pulse detection of a person by a heart rate monitor including a plurality of multi-axis accelerometers adjoined to a platform at different angular orientations with respect to each other, each multi-axis accelerometer having acceleration sensing axes including a vertical axis and at least one of a lateral axis and a longitudinal axis, the method comprising:
spatially mounting, via the platform, the multi-axis accelerometers at the different angular orientations of the multi-axis accelerometers with respect to each other on respective opposing body surfaces of the person, wherein the relative angular orientation of the accelerometers is rigidly maintained by the body surfaces;
generating, via the multi-axis accelerometers as mounted on the person, differential mode signals indicative of a sensing by the multi-axis accelerometers of a physiological motion of the person relative to the vertical axes of the multi-axis accelerometers normal to a body surface of the person;
generating, via the multi-axis accelerometers as mounted on the person, common mode signals indicative of a sensing by the multi-axis accelerometers of an extraneous motion by the person relative to the at least one of the lateral axes and the longitudinal axes of the multi-axis accelerometers parallel to the body surface of the person;
aligning, via the heart rate monitor, the vertical axes of the multi-axis accelerometers relative to an additional baseline axis to combine the differential mode signals and cancel the common mode signals; and
generating, via the heart rate monitor, a pulse signal from the combining of the differential mode signals and the cancelling of the common mode signals as a function of the alignment of the vertical axes of the multi-axis accelerometers.
2. The method of claim 1 , wherein the platform is one of a nose clip, a headband or a head strap.
3. The method of claim 1 , further comprising:
displaying, via a display, a pulse of the person responsive to the pulse signal.
4. The method of claim 1 ,
wherein the vertical axis of each multi-axis accelerometer is normal to the platform; and
wherein the at least one the lateral axis and the longitudinal axis is parallel to the platform.
5. A heart rate monitor for detecting a pulse of a person, the heart rate monitor comprising:
a platform;
a plurality of multi-axis accelerometers adjoined to the platform and having different angular orientations at opposing body surfaces, each of the multi-axis accelerometers having a vertical axis to generate a respective differential mode signal indicative of a sensing by the multi-axis accelerometers of a physiological motion normal to a body surface of the person and a longitudinal axis and a lateral axis parallel to the body surface to generate common mode signals indicative of a sensing by the multi-axis accelerometers of an extraneous motion by the person relative to the at least one of the lateral axes and the longitudinal axes of the multi-axis accelerometers, wherein, in use, the relative angular orientation of the multi-axis accelerometers is rigidly maintained by the body surfaces; and
a pulse detector operably connected to the multi-axis accelerometers to generate a pulse signal as a function of an alignment of the vertical acceleration sensing axes combining the differential mode signals and cancelling the common mode signals.
6. The heart rate monitor of claim 5 ,
wherein the platform is one of a nose clip, a headband or a head strap.
7. The heart rate monitor of claim 5 , further comprising:
a display operably connected to the pulse detector to display the pulse of the person responsive to the pulse signal.
8. The heart rate monitor of claim 5 ,
wherein the vertical axis of each multi-axis accelerometer is normal to the platform; and
wherein the at least one the lateral axis and the longitudinal axis is parallel to the platform.
9. A cardiac therapy device, comprising:
a heart rate monitor according to claim 5 ; and
a pulse monitor operably connected to the pulse detector to monitor the pulse of the person responsive to the pulse signal.
10. The cardiac therapy device of claim 9 , wherein the platform is one of a nose clip, a headband or a head strap.
11. The cardiac therapy device of claim 9 , further comprising:
a display operably connected to the pulse detector to display the pulse of the person responsive to the pulse signal.
12. The cardiac therapy device of claim 11 , wherein the pulse monitor incorporates the display.
13. The cardiac therapy device of claim 9 ,
wherein the vertical axis of each multi-axis accelerometer is normal to the platform; and
wherein the at least one the lateral axis and the longitudinal axis is parallel to the platform.