GB2545740A

GB2545740A - Heart rate and activity monitor system

Info

Publication number: GB2545740A
Application number: GB1522875.2A
Authority: GB
Inventors: Moss Alon
Original assignee: Cloudtag Inc
Current assignee: Cloudtag Inc
Priority date: 2015-12-24
Filing date: 2015-12-24
Publication date: 2017-06-28
Also published as: GB201522875D0

Abstract

A heart rate and activity monitor system has an heart rate monitor sensor package (HMRP) 1 provided with non-contact electrodes sensitive to fluctuations in an electric field induced by heart activity. The HRMP can be used by clamping it to clothing worn by a user. Clamping is achieved by a separable communications package 2 which can be attracted to the HRMP by a permanent magnet 23. In an alternative embodiment, the attachment means can be a spring 6 and clasp. The HRMP includes a power supply module 29 chargeable via inductive wireless charging. When connected to the communications package the HRMP charges a power supply in the communications package. The communications package can be disconnected from the HRMP and mounted into a frame 25 attached to a wrist strap. A motion sensor 27 and thermometer 28 in the communications package can then capture activity data from the wrist of the user.

Description

HEART RATE AND ACTIVITY MONITOR SYSTEM

Technical field

The present invention concerns a system of components and processes whereby a human or animal heart rate (pulse) and other factors indicative of metabolism can be accurately and conveniently sensed and recorded during normal and vigorous activity.

Prior Art

Conventional heart rate monitors detect used to detect a human or animal pules sense the electric field generated by the heart as it progresses through a cycle of contraction and relaxation. Conventionally the electrical potential at the skin surface is sensed via one or more “wet” conductive biosensor electrodes in intimate contact with the subject’s skin. Contact is generally achieved via a conductive gel. However, such systems suffer from a range of well-known problems ranging including a requirement for the skin to be prepared clean and free of hair, and variations in sensitivity caused by metabolic changes such as perspiration and partial or total displacement during activity.

Non-contact sensors have been researched as exemplified by the disclosure in WO2015061282A.

As remarked in WO2015061282A development in “dry” biosensor electrodes has focused on non-contact capacitive sensors in which two capacitive sensors comprising capacitor plates generate signals on two separate channels. Different input load capacitances are provided at each channel. When disposed close to the skin of a subject the input coupling capacitance of each capacitor plate can be determined from the different input load capacitances. The bio-signal can then be recovered using a digital reconstruction filter, from the coupling capacitance. The non-contact sensor, can be carried on clothing or worn on body parts with patches or bands and without requiring direct contact with the skin. Signals from the sensors are collected wirelessly, such as by a smart phone or other portable computer.

In a non-medical environment the main interest in ECG sensing is to determine pulse and hence metabolic rate and performance during exercise. A relatively accurate estimate of energy expended (calories or kilo calories) during exercise can then be calculated from the record of pulse (heart rate) over time and other characteristics of the individual such as weight and age. Non-medical or sports heart rate monitors commonly use a dry contact electrode sensor package containing the bio-electrode strapped to the chest of a user via a band. Such electrodes are susceptible to poor connectivity depending on the condition and preparation of the subjects skin. Signals from the sensor package are fed to a processing and recording device, often a wrist borne device or smart phone via a wire or wirelessly via a protocol such as ZIGBEE®, BLUETOOTH ® or WiFi. Where wireless communication is employed each of the sensor package and PRD must have separate power supplies, usually in the form of compact cells. The cells require frequent inconvenient and expensive replacement.

There is also an interest in monitoring general levels of activity and fitness, that is to say, non-exercise oriented activity throughout a user’s day.

The present invention aims to address at least one of the technical problems described above in a heart rate and activity monitoring system.

Statement of Invention

According to the present invention there is provided a heart rate and activity monitor system comprising: an heart rate monitor package sensor package; a communications package; and wherein the heart rate monitor package contains, a non-contact sensor system capable of sensing changes in a bio-electric field indicative of heart activity, and a rechargeable power supply, and a charge transfer module; the communications package comprising a wireless communications module and a communications package rechargeable power supply; and means to separably connect the wireless communication module to the heart rate monitor package whereby the charge transfer module will transfer charge to the communications package power supply to recharge the communications package power supply.

The main non-contact sensor system present in the heart rate monitor package will advantageously be a pair of capacitance electrodes sensitive to the electric field generated by the heart activity of a user. The heart rate monitor package power supply may include at least one storage cell, to power the systems in the heart rate monitor package such as the sensor electrodes, analogue and digital filters and communication of data, especially heart rate data to the communications package.

The charge transfer module will include means to receive a charge from an external power supply and transfer the charge onto the heart rate monitor package power supply. An external power supply may be any source of electric charge and will preferably be transferred via an inductive charging external power supply to an inductive charging module having a charge storage cell within the heart rate monitor package power supply.

Each capacitance electrode will preferably be protected from external interference by means of an active shield guard ring forming a faraday cage. The capacitance electrodes will receive electric field signals generated by all the subject’s active muscles, not solely the heart. The most consistent activity will be from the subject breathing. Preferably analogue and/or digital filters will operate to isolate signals generated from the heart activity from other electrical signals generated by other muscle activity such as respiration and voluntary muscle activity. In particular the received signals may be amplified by differential amplifiers tuned to filter out noise signals outside the frequency range of the heart generated signals to eliminate motion generated noise. A Driven right Leg (DRL) and/or an active body ground to further reduce motion artefacts, and DC noise generated from the capacitive connection. A fast test signal outside the frequency range of interest to evaluate quality of body connection. An adaptive filter responsive to feedback from the fast test signal to further filter out noise. An adaptive filter based on amplitude to remove poor signals.

The means to separably connect the heart rate monitor package to the communications package power supply will advantageously comprise a permanent magnet arranged to attract a permanent magnet disposed within the communications package. The means to separably connect may further comprise a flexible strap or “U” shaped spring supporting conductors and connectors to electrically connect the heart rate monitor package to the communications package. Where a flexible strap is used the magnetic attraction between the heart rate monitor package and the communications package will be sufficient to enable a span of clothing to be firmly clamped between the heart rate monitor package and the communications package thus securing the combined heart rate monitor package and communications package to the user. The connected heart rate monitor package and communications package can conveniently be clamped around the edge of a sports bra or the collar of a shirt close to the chest and underlying heart.

Charging of the communications package is achieved from the heart rate monitor package while connected.

While connected the signals acquired by the heart rate monitor package are transmitted to the communications package. The communications package then retransmits the signals to a processing and readout device such as an application equipped smartphone or any other computer to be recorded processed and stored.

When the heart rate monitor package is not in use it may be stored connected to a charger, preferably an inductive charger.

The communications package may contain additional sensors such as a temperature sensor or acceleration sensor. The communications package may be adapted to be coupled to a body fastening such as a wrist band, finger ring, brooch, thigh band, ankle band, belt, or headband whereby it can be secured to a subjects wrist, finger, leg, lower torso, neck or forehead to capture data from the movement and general activity of the user.

Brief Description of the Figures

An embodiment of a heart rate and activity monitor system constructed in accordance with the present invention will now be described, by way of example only, with reference to the accompanying illustrative figures, in which:

Fig 1 is an isometric view of an heart rate monitor package and communications package separated, to be brought into contact;

Fig 2 is an isometric view of the heart rate monitor package and communications package coupled together for use during exercise;

Fig 3A is an isometric view of the heart rate monitor package with the cover removed to show some internal details;

Fig 3B is a side elevation of the communications package;

Fig 3C is a bottom view of the communications package:

Fig 4 is a sketch of the connected heart rate monitor package and communications package clamped to a sports bra during use;

Fig 5A is an isometric view of a wrist band and mount for the communications package;

Fig 5B is an isometric view of a wrist band with the communications package mounted; and

Fig 6 is a block diagram of the system components.

Detailed Description

The system of the embodiment shown comprises an heart rate monitor package 1 sometimes known as a Smartag ™ a communications package 2 sometimes known as the Pill ™ and a wrist band 3. The heart rate monitor package 1 comprises a rear or skin side housing part 4 intended to sit next to the skin of a user. A front housing part 5 is secured by screws to the rear housing part 4 to form a sealed hollow enclosure. A “U” shaped spring 6 extends from a base of the HRMP 1 to support a clasp 7 having two resiliently deformable arcuate horn shaped elements 8 adapted to engage in a groove 9 extending around the periphery of the communications package 2.

Conductors (not shown) run through the spring 6 from the electronics in the heart rate monitor package 1 to connectors 10 which couple with corresponding connectors 11 formed in the underside of the communications package 2.

Figure 6 illustrates the electronics in the HRMP 1 and communications package 2.

The electronics in the HRMP 1 is powered by a heart rate monitor package power supply 29 comprising a rechargeable chemical cell and an inductive charging module In the HRMP 1 the electric field generated by a heart pulse is sensed by a pair of non-contact capacitance sensors 12. The sensors are shielded from external electric fields by an active shield 13. Signals received from the capacitance sensors 12 are filtered by a low and high pass differential amplifier 14 to isolate signals with the frequency appropriate to a heart pulse, ie approximately 0.6Hz to 3.3 Hz. A high frequency fast test signal is generated by the module 15 and emitted from the sensors 12. The response is sensed by the sensors 12 to confirm reliable sensor coupling with the body’s electric field and to control a further active filter 16 responsive to the coupling from the fast test filter. Finally an amplitude band filter 17 removes signals with an amplitude exceeding or below the amplitude expected from a heart.

The filtered signals are fed to a communications module and transmitted via conductors in the spring 6 to the communications package 2.

Communications package 2 includes an input module 18 to communicate signals received from the HRMP 1 to wireless communications module 19 which transmits the data signals to a recording and processing device such as a smart phone (not shown). The communications package 2 includes a communications package power supply 20 including a power storage cell charged by charge received from the HRMP power supply 21 during connection over two or more of the conductors in the spring 6.

In use the communications package 2 is mounted into the clasp 7 which is then clamped around the edge of an item of clothing such as the bottom of the sports bra 22 as shown in figure 4. A magnet 23 is disposed in the HRMP 1 and works in concert with a magnet or ferromagnetic material (not shown) provided in the communications package 2 to close the gap between the front of the HRMP 1 and the back of the communications package 2. To further enhance the grip of the system on the fabric ribs 24 are formed on the front of the HRMP 1.

When the communications package 2 is charged and recordal of an accurate heart rate is not desired the communications package 2 can be separated from the clasp 7 and secured in a frame 25 attached to a wrist strap 26 as shown in figure 5A and 5B.

In this condition sensors such as an accelerometer 27 and thermometer 28 are able to sense motion and temperature of the user and produce an indication of activity throughout the day.

When not in use to determine heart rate the HRMP can be charged using a substantially conventional inductive charger communications package 2 is retained in the frame 25 by means of a spring loaded latch 26. Depressing the latch releases the communications package 2.

Claims

1. A heart rate and activity monitor system comprising: a heart rate monitor sensor package (1); a communications package (2); wherein the heart rate monitor package (1) contains, a dry sensor system capable of sensing changes in an electric field generated by heart activity, and a rechargeable power supply (29), and a charge transfer module; the communications package comprising a wireless communications module (19) and a communications package rechargeable power supply (20); and means to separably connect the wireless communication module to the heart rate monitor package whereby the charge transfer module (31)will transfer charge to the communications package power supply to recharge the communications package power supply.

2. A system according to claim 1 wherein the dry sensor is a capacitive non-contact sensor.

3. A system according to claim 1 or claim 2 wherein the charge transfer module (30) comprises an inductive charging sub-system to receive charge from an inductive charger.

4. A system according to claim 1 or 2 where in the means to connect comprises a spring (6).

5. A system according to any one of the preceding claims wherein the means to separably connect the wireless communication module (19) to the heart rate monitor package (1) comprises conductors in the spring (6).

6. A system according to any one of the preceding claims wherein at least one of the HRMP (1) and the communications package (2) contains a permanent magnet (23) to attract a corresponding permanent magnet or ferromagnetic element in the other of the HRMP (1) and communications package (2) to facilitate clamping the system to the fabric of a garment captured between the HRMP (1) and communications package (2).

7. A system according to any one of the preceding claims wherein the communications package (2) contains additional sensors selected from any of: (a) motion sensor (27) or (b) a thermometer (28).

8. A system according to claim 7 wherein the communications package (2) can be detached from the spring (6) and secured into a frame (25) to be worn or carried elsewhere on the body.

9. A system according to claim 8 wherein the frame is carried on a wrist strap.

10. A system according to any one of the preceding claims wherein a clasp (7) is provided to separably secure the communications package (2) to the spring (6) in order to form a resilient clamp.

11. A heart rate and activity monitor system comprising: an heart rate monitor package sensor package (1); a communications package (2); and wherein the heart rate monitor package (1) contains, a dry sensor system capable of sensing changes in an electric field generated by heart activity, and means to separably connect the HRMP (1) to the communications package (2) to form a clamp capable of gripping fabric between the HRMP (1) and the communications package (2) in order to secure the HRMP (1) against a body and sense electric field emissions indicative of a heart pulse.

12. A system according to claim 11 wherein the means to separably connect comprises a permanent magnet (23) in one of the HRMP (1) or the communications package (2) and a permanent magnet or ferromagnetic structure in the other of the HRMP (1) or communications package (2).

13. A system according to claim 11 or claim 12 wherein the means to connect comprises a spring (6) and a clasp (7) whereby the communications package (2) can be separably attached to the clasp (7).

14. A system according to any one of claims 11 to 13 wherein the communications package (2) provides a wireless communications module (19) to communicate data captured by the HRMP (1) to an external recorder.