GB2509945A

GB2509945A - Swimming Performance Monitoring Device

Info

Publication number: GB2509945A
Application number: GB1300919.6A
Authority: GB
Inventors: David William Baddeley; Kieran James Sloyan; Philip John Maxwell
Original assignee: 222 SPORTS Ltd
Current assignee: 222 SPORTS Ltd
Priority date: 2013-01-18
Filing date: 2013-01-18
Publication date: 2014-07-23
Also published as: GB201300919D0

Abstract

A swimming performance monitoring device 10 which monitors a swimmers progress and can output a number of swimming performance statistics. The monitoring device is housed in a watertight enclosure 12, which includes a means for attaching the device onto the user, and a number of sensors that can be used to derive performance information. The device contains a processing system which uses the data supplied by a capacitance sensor 13, to determine when the swimmer is engaged in swimming activity, and disregard activity outside the swimming pool. Preferably the device is mounted by a strap 11 to a users wrist.

Description

Swimming Performance Monitoring Device [1] This invention relates to a sports performance monitoring device particularly although not exclusively for use in a swimming pool.

[2] Particularly but not exclusively the invention relates to a watertight wristband that records and / or displays the number of lengths, pace, distance, stroke type, stroke rate and any number of performance parameters that can be calculated using the data recorded during swimming activity.

Background of Invention

[3] Swimmers interested in performance related information are also keen to focus on their swimming and technique, and do not want to be concerned with the need to interact with a performance monitoring device while swimming.

[4] Swimmers that wish to wear a performance monitoring device are also concerned with its physical size and reliability, especially as it needs to operate in a harsh environment.

[5] Many popular swimming watches such as the Speedo® Aquacoach® gonoratc swimming porformancc rosults whilo swimming, however the swimmer is required to start and stop the device manually. The major disadvantage or problem associated with such devices is the need to physically interact with the device using these buttons, which are required to avoid non-swimming activity being recorded, which would reduce the accuracy of the swimming performance data generated.

[6] The addition of buttons to facilitate a user interface and associated waterproofing of those buttons also adds to the complexity, cost and enclosures size thus increases the drag associated with the device when swimming.

[7] The invention aims to eliminate or reduce such problems by providing a new swimming performance monitoring device that requires no interaction during exercise to operate, and does not require any buttons to operate.

Summary of the Invention

[81 According to the invention there is a swimming performance monitoring device which consists of a watertight enclosure containing a processing unit, a capacitance sensor and other motion sensors, that can be used to derive performance statistics regarding the swimmers activity. The output signal from the capacitance sensor changes as the swimmer enters and exits the swimming pool thus the period over which swimming activity has occurred can be determined.

[9] Preferably the performance monitoring device attachment mechanism is via an adjustable strap which enables the device to be attached to a swimmers wrist, thus allowing strokes where the swimmers hand enters and exits the water to be detected by the capacitance sensor.

[10] Preferably one of the motion sensors is a three axis accelerometer, the output data from which can be used to determine the swimmers stroke type.

[11] The invention may include a display on the enclosure that allows swimming performance statistics to be displayed while the swimmer is in the swimming pool.

[12] In a preferred embodiment the swimming performance monitoring device logs all the data from the capacitance and motion sensors so that it can be analysed after the swimming activity has taken place. This post analysis capability enables the device to function with or without a built in display, thus further reducing the burden on the swimmer and reducing the devices complexity.

[13] In a preferred embodiment the swimming performance monitoring device includes an interface to enable the device to be connected to a computer with access to the internet, thus allowing the swimmer to retrieve swimming statistics which can then be analysed via software operating on a remote and / or local computer system.

[14] In a preferred embodiment the swimming performance monitoring device processor is programmed to determine if changes in the capacitance sensors output cross pre-set upper and lower thresholds, to indicate if the device is under water or out of water and to determine if a signal in the capacitance sensors output represents swimming strokes.

[15] In a preferred embodiment the capacitance sensor is calibrated so that the underwater output level is only triggered when the device is submerged, and not when it is in proximity to small quantities of water.

[16] In a preferred embodiment the capacitance sensor is calibrated so that the out of water output level is only triggered when the device is not completely submerged, but may be in proximity to small quantities of water.

[17] In a preferred embodiment the device includes a means to determine the time which has elapsed during a swimming session.

Brief Description of Drawings

[18] The invention will now be described by way of example only, with reference to the following drawings, in which; [19] Figure 1 is a front view of an embodiment of a swimming performance monitoring device, where the device enclosure is mounted to the swimmer by means of a wrist strap.

[20] Figure 2 is a chart that shows the typical output waveform from the capacitance sensor entering and exiting a swimming pool, when the swimming performance monitor is worn on a swimmers wrist.

[21] Figure 3 is a chart that shows the typical output waveform from the capacitance sensor, when the swimming performance monitor is worn on a swimmers wrist that is performing freestyle.

[22] Figure 4 is a functional block diagram of the swimming performance monitor including a capacitance sensor.

[23] Figure 5 is a flow chart that shows how the swimming performance monitor determines when to start and stop generating swimming statistics and / or recording swimming data, based on the output from the capacitance sensor.

Detailed Description of the Preferred Embodiment

[24] Referring to figure 1 of the drawings there is shown a swimming performanoe monitoring device 10 for use by a swimmer, which consists of a watertight enclosure 12 containing the processing unit and capacitance senscr 13. An adjustable strap 11 attaches the watertight enclosure to the wrist or ankle of the swimmer.

[25] The means of attachment of the device 12 could be adapted to fit around another part of the swimmer. In a different embodiment the device 12 may be attached using a belt so that the swimming performanoe monitoring device could be attached to the swimmer waist. Alternatively a mechanism may be used so the device 12 can be attached to a swimmers head cap, goggles or other clothing and accessories.

[26] The swimming performance monitoring device 10 is controlled by an electronic circuit based around a microcontroller 60 which is programmed to carry out all the device functions.

[27] A communications interface 14 forms part of the swimming performance monitoring device 12. This is connected to and controlled by the microcontroller 60, which enables the device to communicate with external computers and / or mobile handheld devices. This enables the swimmer to analyse their swimming performance data on any number of different technology platforms. In the preferred embodiment this is a USB (Universal Serial Bus) communication link, but could be an alternative electrical and / cr radio and /or cptical based communications interface.

[28] A capacitance sensor 13 is housed within the swimming performance monitoring device enclosure 12. This is connected to the microcontroller 60, allowing capacitance readings to be taken by the microcontroller. The capacitance sensor 13 consists of a sensing element that is positioned close to the top of the enclosure 12, so that water surrounding the performance monitoring device 10 has the effect of increasing the capacitance reported by the device since the permittivity of the water is far greater than that of surrounding air.

[29] An accelerometer 63 is connected to the microcontroller 60, allowing additional swimming performance data to be sampled by the microcontroller.

[30] A solid state Flash memory device 61 is connected to the microcontroller 60. In an alternative embodiment of the device an alternative storage medium may be used. The memory device 61 allows the microcontroller 60 to record any swimming performance results obtained from either the capacitance sensor 13 and / or the accelerometer 63.

[31] In the expected operating scenario the swimmer attaches the performance monitoring device 10 to their body prior to performing any swimming activity. They may then enter the swimming pool at any given point in time after attaching the device 10 to their body. They may for example go to the gym before going for a swim while still wearing the swimming performance monitoring device 10 and not go swimming. While swimming the swimmer may decide to leave the swimming pool for a rest, or to get changed while still wearing the swimming performance monitoring device 10. The swimmer may then remove the device 10 at any given point in time following the swimming activity.

[32] Figure 2 shows a typical waveform output by the capacitance sensor 13 when the swimming performance monitor is worn on the wrist of a swimmer. The waveform contains a number of distinct features. Feature 20 shows a significant drop in the output of the capacitance sensor that relates to an increase in capacitance cause by replacing the air surrounding the capacitance sensor 13 with the water of the swimming poo1.

In this example the swimmer is performing breast stroke, which means their wrist is always under the water. Feature 21 at some point in time later during the swim, shows an increase in the output of the capacitance sensor 13 caused by the swimmer removing their wrist from the swimming pool. This change in capacitance is used by the microcontroller 60 to start and stop the recoding of swimming performance data to the memory device 61.

[33] The change in capacitance caused by a swimmer entering and exiting the pool as shown in Figure 2, allows performance data relating to non-swimming activities to be discarded by the microcontroller 60. Only true swimming performance data will be recorded to the storage device 61.

[34] Figure 3 shows a typical waveform output by the capacitance sensor 13 when the swimming performance monitor is worn on the wrist of a swimmer during freestyle, backstroke or butterfly. The waveform contains a number of distinct features. Feature 30 shows a significant drop in the output of the capacitance senscr 13 as the swimmers wrist and thus the attached swimming performance monitoring device 10 enters the swimming pod during a swimming strcke. Feature 31 shows a significant increase in the output of the capacitance sensor 13 as the swimmers wrist exits the water. The waveform shown in figure 3 is recorded to the memory device 61 via the microcontroller 60.

[35] Figure 5 describes the process by which the microcontroller 60 determines when to start and stop recording swimming performance data, thus ensuring that all swimming based performance data is recorded to the device.

[36] When operational the device 10 is not recording swimming performance data. Instead the capacitance sensor 13 is sampled to determine if the device 10 is under water. The data returned by the capacitance sensor 13 is averaged over N samples 41, where N is optimised to reduce the likely hood of false readings but not take too much time to return a capacitance reading.

[37] The output from process 41 is then compared against the underwater threshold °thres to determine if the device 10 is submerged. If the reading drops below the threshold C-bres, then a flag 43 is set true to declare the device is now recording swimming performance data. At the same point in time 44 the capacitance reading and accelerometer sensor readings are stored to the memory device 61 by the microcontroller 60.

[38] Soon after being submerged under water the device 10 may exit the water if the swimmer is performing a stroke as described in figure 3. To ensure this change detected by the capacitance sensor 13 does not trigger the microcontroller to stop recording valid swimming data, a timer is used to record the amount of time which the device 10 is cut of the swimming pool, following the start of recording. This timer 45 is reset when the capacitance sensor 13 detects that it is underwater in process 41.

[39] If during the next time around the process loop 41 the reading shows the device 10 is out of the water and the result is not smaller than the threshold CLhrCH, then the timer is incremented 47.

[40] If the timer value ever exceeds the variable 48, then the device 10 has been out of the water for too long for it to be a normal swimming stroke as shown in figure 3. At this point the recording is stopped 49, and the device 10 is put into a sleep mode for T 50. At this point the microcontroller stores a small amount of data 51 in the storage device 61 that relates to the amount of time for which the device 10 has not been recording swimming performance data.

[41] Ibis timing data can be used to provide statistics to detail the amount of rest time taken between swimming activity recorded to the device 10.

[42] The variable T-1 is set to a period of time several times greater than a complete swimming stroke would ever take. This ensures that any swimming activit will be recorded when the swimmers wrist, and thus device 10 is in the water at some point every few strokes.

[43] The variable Toat is also set to a period of time several times smaller than a usual rest during swimming activity would last. This ensures that any non-swimming activity outside of the swimming pool will not be recorded where the swimmers wrist, and thus device 10 is out of the water for an extended period of time.

[44] In this the preferred embodiment of the device the variable lies between a minimum of 10 seconds and 2 minutes to ensure correct operation. The exact value of T0t can be modified depending on the type of swimming activity and intensity to be expected depending on the swimmers ability.

This will enhance the performance of the device 10.

[45] The variable T is set to a time period several times greater than the sampling time period of the microcontroller 60. This ensures that a significant power saving and storage device 61 memory saving is achieved when the device 10 is not recording swimming performance data, and that the device can be used by the swimmer for more than just one swimming session.

[46] The variable T is also set to a time period smaller than that of the reguired response time for the device 10 to start recording when it enters the swimming pool. This ensures that no swimming performance data, of significance to the swimmer fails to be recorded as they enter the swimming pool.

[47] In this the preferred embodiment of the device the threshold CLtires, is set to the following level; Cthres = Cmin + 0.2 x (max -Cmin) [48] Where C-is the capacitance sensor 13 output when the device 10 is fully submerged under water, and Crtx is the sensor 13 output when the device is surrounded by air. Setting the threshold closer to the minimum value reduces the risk that recording starts when the device 10 is taken into a damp environment prior to swimming activity taking place.

[49] The invention has been described by way of example only, and different modifications of the preferred embodiment may be made by people skilled in the art without departing from the scope of the invention as laid out in the following claims.

Claims

Claims i. A swimming performance monitoring device for use by a swimmer, which contains a capacitance sensor to provide an output which can differentiate between when the device is under water, and when it is out of water.
2. A swimming performance monitoring device according to claim 1, which is housed within a waterproof enclosure.
3. A swimming performance monitoring device according to claim 1, includes an electronic circuit that uses the output from the capacitance sensor to automatically start and stop recording swimming performance data without any input what so ever from the swimmer wearing the device.
4. A swimming performance monitoring device according to claim 1, wherein the recording of accelerometer data is started and stopped automatically, based on the analysis of a capacitance sensor output to ensure the data recorded is related to swimming activity.
5. A swimming performance monitoring device according to claim 1, wherein the recording of accelerometer data is started and stopped automatically, based on the analysis of a capacitance sensor to ensure the data recorded is not related to activity outside of a swimming pool or other body of water.
6. A swimming performance monitoring device according to claim 1, wherein the method of attachment is a wrist strap.
7. A swimming performance monitoring device according to claim 1, wherein the method of attachment is a waist strap.
8. A swimming performance monitoring device according to claim 1, wherein the capacitance sensor output is used to put the device into a low power sleep mode when it is not in a swimming pool to increase the endurance of the device.
9. A swimming performance monitoring device according to claim 1, wherein the capacitance sensor output is used to avoid the need to incorporate any external buttons or user interface on the device.
10. A swimming performance monitoring device according to claim 1, wherein the capacitance sensor output is recorded so that when later analysed the results can be used to generate swimming statistics relating to swimming activity only.