January 25, 2016

Dr. Andrew Rawicz School of Engineering Science Simon Fraser University Burnaby, British Columbia V5A 1S6

Re: ENSC 305/440 Capstone Project Proposal for Athletic Balance Monitoring System

Dear Dr. Rawicz,

The enclosed document is the proposal document for our Capstone project: the Athletic Balance Monitoring System, specifically for skiers. Our objective with this project is to design and build a system that can assist an athlete in furthering their abilities by collecting quantitative data on their performance and converting it into useful real-time feedback.

This document consists of a system overview and component breakdown of our design, details on our budget and funding, as well as an overview of our project timeline and task breakdown. Moreover, it includes an analysis on the current market and the reasoning behind our speculation that it will thrive.

Pinnacle Biometrics is comprised of four SFU engineering science students: Kurtis Bohlen, Eric Raposo, Louis Roux, and Clara Tsang. Specializing in systems and electronics, we are motivated and passionate about our fields of study and the use of technology to help athletes meet their true potential.

Please do not hesitate to contact me at clarat@sfu.ca if you have any questions or concerns in regards to this submission. On behalf of my team at Pinnacle Biometrics, I thank you for time and consideration of our proposal.

Sincerely,

Clara Tsang

Project Manager, Pinnacle Biometrics

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Executive Summary

With an estimated 115 million skiers worldwide [1], the international ski market has the size and resources to support a multitude of enterprises dedicated to a variety of aims. Canada itself is the 7th biggest market for downhill skiing and snowboarding in the world, capturing 5% of worldwide visits to ski areas [1]. This translates to over 19 million skier visits every year, with 34% of them (6.5 million) taking place in British Columbia [2]. All told, the BC ski and snowboard industry has a total economic output exceeding $1 billion every year [2].

Intrinsically an expensive sport to participate in due to the costs of the required equipment, the market for alpine sport is supported by a relatively wealthy audience. The increasing trend of technology-assisted augmented learning has established a stable presence within that market. Most technological accessories available on the market for alpine sport enthusiasts feature the real-time display of basic movement statistics, whereas most wearable biofeedback technologies are focused on cardiovascular metrics. Centre of pressure metrics can be very useful to the skier as it can be difficult for one to gauge their balance, an essential element to skiing properly, while moving on a slope. Through the combination of the existing technologies mentioned above, as well as balance-sensing technologies generally kept within the bounds of biomedical research and gait monitoring, we are working to design and build a device to provide both the amateur and professional skier with real-time useful balance feedback.

This document proposes Floe, the athletic balance monitoring system specialized for skiers. Through biometric data collection and analysis along with Bluetooth LE technology, Floe can provide the user with real-time prescriptive feedback through a head-up display as they are going down the slopes, as well as record and save intervals of performance for post-activity review on their mobile device off the slopes. This document will provide details on the system overview, component breakdown, budget and funding, project breakdown, as well as analysis of the market and a projection of its place in it.

Pinnacle Biometrics consists of four SFU engineering science students with systems and electronics backgrounds, experienced in Bluetooth technology, signal processing, microcontroller programming as well as high-level software.

The tentative deadline for the completion of this project is April 1, 2016. We have calculated the budget of the entire project to be approximately $1,500.00, and are expecting funding from multiple sources.

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Table of Contents

Executive Summary ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i i

Table of Contents ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i i i List of Tables and Figures ........................................................................................................ iii

1 Introduction ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

2 Scope .... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2.1 Possible Solutions ........................................................................................................... 2 2.2 Proposed Solution ........................................................................................................... 2

2.2.1 Hardware Overview .................................................................................................. 2 2.2.2 Software Overview .................................................................................................... 3

2.3 Risks & Benefits .............................................................................................................. 4 2.3.1 Risks .......................................................................................................................... 4 2.3.2 Benefits ...................................................................................................................... 4

3 Market Research .... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3.1 Existing Alpine Sport Accessories .................................................................................. 5 3.2 Existing Pressure-Sensing Products ............................................................................. 6 3.3 How Floe Fits in the Market ............................................................................................ 7

4 Company Detai ls .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 4.1 Team Members ............................................................................................................... 8 4.2 Team Structure ............................................................................................................... 8

5 Project Planning .... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

6 Cost Considerations .... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 6.1 Budget ........................................................................................................................... 10 6.2 Funding .......................................................................................................................... 11

7 Conclusion .... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

References .... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

List of Tables and Figures Figure 1.1 – Floe concept 1

Figure 2.1 – Hardware breakdown 3

Figure 2.2 – Software GUI breakdown 3

Figure 3.1 – Existing alpine sport accessories 5

Figure 3.2 – Existing pressure sensing products 6

Figure 5.1 – Project breakdown Gantt chart 9

Figure 5.2 – Project milestone chart 9

Table 6.1 – Bill of materials 10

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1 Introduction British Columbia is a hub for alpine sport enthusiasts, attracting as many as 1.2 million

visitors to the Whistler ski resort alone annually [3]. The alpine sports’ popularity is rising, not only among locals for whom the Rockies are a commonplace sight, but also for foreigners, whose growing wealth is permitting more spending on leisure.

Those who want to learn how to ski or snowboard face a steep learning curve. The alpine sports require a unique mix of forethought, alertness, physical fitness and balance to execute properly, which makes professional instructors and trainers an expensive commodity that not all would-be skiers can afford. Furthermore, although the amount of qualitative analysis on athletic performance is plentiful through the eyes of instructors and coaches, there is a lack of quantitative data available to amateur skiers, especially real-time feedback, which would commonly be offered by an instructor.

Qualitative analysis and feedback is quick and more detailed on the scope of a single test situation, but it is subjective, more difficult for comparison with other tests, and less consistent [4]. Quantitative analysis would allow for the user to receive consistent, objective feedback as well as easily compare multiple instances of their performance.

Qualitative verbal feedback, as would be offered by a coach, is most effective at the beginning of one’s learning; this period of learning can be referred to as the first stage in Gentile’s two stage learning model. The suggests that once the learner enters the second stage, in which the learner has grasped the basics of the skill being learned, augmented feedback on their knowledge of performance is what will greatly enhance their learning of the skill [5].

Figure 1.1 Floe concept

At Pinnacle Biometrics, we are proposing Floe: the Athletic Balance Monitoring System to provide the user with accessible quantitative analysis on their performance. Not intended for use of a fresh beginner, Floe offers the addition of quantitative augmented feedback for both the amateur and professional skier.

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2 Scope This section will cover the system overview of our product, as well as elaborate on the

reasoning behind our design and features. The potential risks and benefits of our product will also be discussed.

2.1 Possible Solutions There are several methods of performance analysis for augmented feedback currently

existent in the market. Through the comparison of existing technologies in athletic performance analysis and biomedical analysis, we considered the following solutions in allowing for accelerated learning in athletes.

Video Performance Analysis

A popular method for augmented analysis on athletic performance is to review one’s performance through video recording. Although this is highly feasible and effective for sports in which the athlete is relatively stationary or within a smaller range (i.e. Baseball, basketball), the recording of alpine sports would require the camera to follow the skier down the slope. We found this idea to be unsuitable, as the project would be extensively based on mechanical concepts. This method also would not offer the user real-time feedback.

Biometric Analysis with Haptic Feedback

This design consists of a force-sensitive insole within the boot to collect weight distribution data of the user and an apparatus to provide prescriptive feedback through vibration. Humans respond faster to haptic feedback than visual feedback, and this design would allow us to keep the system all in the boot. However, the vibration caused by our system would be greatly interfered with the vibration on the ski and boots intrinsic to skiing.

2.2 Proposed Solution Floe is based on applying existing gait monitoring concepts to a new, specialized

integrated system that will analyze the collected weight distribution data of a skier and return useful information directly to the subject, in real-time or downstream review.

2.2.1 Hardware Overview As can be seen in Figure 2.1, three main components constitute the system: a force-

sensitive insole, a SoC, and a user interface. Six piezoelectric force-sensitive resistors will be distributed in an array on each insole, secured through lamination with two sheets of heavy-duty film, to sense the weight distribution of the user during their performance. The SoC will receive data from the FSRs and convert the received analog signals into digital to be sent in data packets via Bluetooth LE to the user’s device for analysis and data display in real-time. While the insole is simply inserted in the user’s ski boot, a waterproof, impact-resistant casing containing the SoC and power supply will be mounted onto the exterior of the boot. Aside from an Android mobile device, we will be integrating Recon Instruments’ Snow2 goggle head-up display into our design as the means for real-time feedback. Details on the physical system components can be found in Section 6.1.

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Figure 2.1 – Hardware breakdown

2.2.2 Software Overview The user interface consists of two modes: real-time prescriptive feedback on the

Snow2 goggle display, or event recording for post-activity review on an Android mobile device.

The software of the system is required to calibrate and analyze the data received from the FSRs in the boot to determine usable prescriptive feedback as well as display for the user recorded events for review and comparison. This requires for the software to be based on mathematical concepts including calibration and differentiation, as well as Newtonian ideas on object forces on slopes.

Figure 2.2 – Software GUI breakdown

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Prior to performance, the user will select which mode to initiate on their mobile device.

When selected, the real-time feedback of the system will be displayed on the goggle display as shown in the right of Figure 2.2, indicating to the user in a non-distracting manner where their weight distribution is and how to center it again.

The post-activity review on the mobile device will record the weight distribution and display it as a playback as shown on the left of Figure 2.2, or as a Centre of Pressure-vs.-Time line chart to be compared with other recorded events.

2.3 Risks & Benefits

2.3.1 Risks Widely known as one of the world’s more dangerous sports, encouraging the user to engage with a device while skiing will come with its risks. The most significant of the few is that of distraction from their surroundings, which would heighten all risks intrinsic to skiing. Other risks include that of incorrect information and feedback, causing confusion to the athlete during their performance, as well as system failure due to environmental factors or impact.

Because such a device has the potential to impose such risk on its user, we must be very diligent in preventing these cases from happening and implement extensive safety mechanisms. The real-time feedback display must be unobtrusive and minimalistic to not divert the user’s attention from his surroundings; it must be easily ignored if the user so chooses. The software must be heavily tested to ensure no transmission of faulty information. Lastly, the casing of the system must be heavily reinforced to withstand environmental factors such as temperature, moisture, impact, and motion.

2.3.2 Benefits The main advantage of this product is that it will allow athletes to accelerate their learning of physical skills. Athletes will be able to receive real-time feedback on their performance gathered from quantitative data. With real-time prescriptive feedback, and consequently fall prevention capabilities, as a feature of the system, Floe can also increase the safety for amateur skiers. Furthermore, whereas existing biofeedback technologies mainly circulate within the field of cardiovascular metrics displayed on users’ wrists, Floe allows for the user to view their progress conveniently in an unobtrusive head-up GUI.

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3 Market Research The international ski market, with its 115 million yearly skiers, is a market with the

resources to support a multitude of different enterprises with various products and goals [1]. Canada is one of the largest markets in the world, with 6.5 million skier visits to ski areas in British Columbia alone every year [2]. Indeed, even in countries with the largest ski markets only a small proportion of the population (typically less than 5%) practices downhill skiing or snowboarding [1].

Skiing is traditionally a sport practiced by a mostly well-off clientele, given the large investment required to acquire suitable equipment. Professional athletes spend large sums to access the guidance of a professional trainer, and are ready to make any sacrifice to improve their performance further. Easy access to enticing metrics about sports performance has also increased the demand for quantitative metrics by the more casual segment of the sport’s practitioners. Such casual users, by their large numbers, combined with the rise of mobile technology, have spurred companies to develop a plethora of devices intended to monitor and quantify one’s performance in a sport.

3.1 Existing Alpine Sport Accessories

In the domain of downhill skiing and snowboarding, notable devices are the Trace [6], the Yeti [7], the Flaik [8] and the Piq [9]. These devices all serve the same basic purpose, and provide similar data about an individual’s performance. They all use GPS technology

Figure 3.1 (a) Trace activity monitor [6]

Figure 3.1 (b) Yeti wrist monitor [7]

Figure 3.1 (c) Flaik GPS device [8] Figure 3.1 (d) Piq ski accessory [9]

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to track the user’s speed, altitude, distance covered, and airtime. Such metrics could easily be tracked by the user’s smartphone, using the appropriate application, without the need for an additional device. Indeed, the Snow2 goggles we use as part of this project also have the ability to measure such metrics [10].

The Trace sets itself apart with a 9-axis sensor and its ability to distinguish between different tricks performed by the user [6]. The Piq, probably the most advanced device currently on the market, also features sensors that measure g-force on landing from jumps, carving angle during turns, and edge-to-edge speed of the skis [9]. It is important to note that none of these devices have the ability to feed the user such data in real time; they are limited to storing the data for later review by the user.

3.2 Existing Pressure-Sensing Products In the realm of foot-pressure sensing technology, the market already has some

important players with interesting products. A research team at Carnegie Mellon University has developed SENSEable Shoes, pressure-sensing shoes that can recognize different types of movement and use these to perform different control actions such as controlling a slideshow with high accuracy [11]. Their product uses six pressure sensors per foot and transmits the data to a laptop to do the data processing and act out the control actions.

Figure 3.2 (a) Go-Tec 2304 foot plate [12]

Figure 3.2 (b) Tekscan F-Scan [13]

A number of pressure-sensing foot plates, with a much higher resolution, are also on the market. For example, the Go-Tec features 2304 pressure sensors arrayed in a 38cm x 38cm area [12]. These sensors transmit data to a computer, which can analyze it to give user information about his posture and gait. Obviously, such a device is not usable by an athlete during performance, and is meant for use in a lab or medical clinic. It does, however, give a good idea of how accurate sensing technology can be.

A third notable product in the field of pressure-sensing is the F-Scan system by Tekscan. The system consists of a pair of flexible, thin insoles covered in pressure sensors that are connected via wires to a recording/transmitting device worn by the user [13]. The insoles offer a great resolution for the pressure data, and can be trimmed down in size to be used in any type of footwear. The data can be transmitted in real-time to a nearby computer for analysis and display, and recorded for later review. The high level of

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detail provided by such insoles could be very useful for the purposes of our product, however it is very likely that a high number of sensors would make it difficult to provide real-time prescriptive feedback to the user at a reasonable rate.

3.3 How Floe Fits in the Market Documents produced by the international ski industry clearly indicate that, although the

market has a lot of room to grow, an important barrier to growth is the lack of retention among new skiers [1][2]. This issue arises from the fact that such sports are difficult to learn, and professional training sessions are very expensive. Floe, with its prescriptive feedback technology, is uniquely placed to make learning the sport easier, thus help the market grow further. Ski schools could use our product to turn more new skiers into returning customers quicker, thus growing their business at an accelerated pace. At a price point of around $200, once economies of scale from mass production and some markup to account for our own business expenses are taken into account, our product would be affordable enough for ski centers to purchase multiple units for use in their ski schools, and for dedicated members of the public to acquire for themselves. This price point would also be competitive with rival performance tracking devices, whose prices vary between $150 (Trace) and $300 (Yeti).

Floe is poised to make a good entry onto the performance tracking device market with its unique real-time and prescriptive feedback features. To start off, we will rely on support from private investors and crowd funding while we perfect our product and work out the kinks in the period leading up to the official product launch. Our first customers are likely to be private individuals eager to try out Floe for themselves. These people are an important audience, as they are likely to be our most enthusiastic promoters. These early adopters will make Floe better known, thereby giving us the visibility and credibility required to make a larger break into the market. Within at most two years from launching the product, we expect to be able to secure a few sizeable deals with large ski stations and sporting goods stores. This will fund the development of more technologically advanced future offerings. By that time, we expect to possess approximately 10% of the market for ski- and snowboard-centric performance tracking devices.

Future designs could easily incorporate more common metrics, which would allow us to capture an even larger part of the market by offering a product that encompasses all areas of performance tracking for that sport.

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4 Company Details

4.1 Team Members

Kurtis Bohlen | Hardware Lead

Kurtis is a fourth-year Electronics Engineering student. He has experience using a similar Nordic Semiconductor BLE SoC to read electrochemical gas sensor data and transmit it over the BLE protocol from a special projects laboratory course he took previously. This, along with other past electronics based projects will provide him with the ability to handle all of the hardware and assist with the BLE firmware development on the Nordic SoC.

Clara Tsang | Software Lead

Clara is a fourth-year Systems Engineering student. Though most of her programming experience is in C and C++, she has also worked with SQL, HTML, ARM, and HC-12 assembly. Her last co-op placement was at a building engineering firm in HK, where she worked extensively with energy audit data collection and analysis. Her past experiences, initiative, and passion for math motivate her to be an effective software lead and project manager for the team.

Eric Raposo | Firmware Lead

Eric is a fourth-year Systems Engineering student, ad will be working on the real-time communication system. His previous co-op experience took place within the firmware department of a local tech company and provided him with extensive knowledge in C, C++, C#, and real-time system design. He is very interested in the Bluetooth LE protocol and excited to develop efficient wireless data transmission. He will also be working closely with the hardware and software to integrate the system and develop the GUI. His resourcefulness and passion for learning make him an ideal real-time system designer for Floe.

Louis Roux | Mechanical Lead

Louis is a fourth-year Systems Engineering student. He is in change of the mechanical design for integrating the pressure-sensing insoles and SoC components onto the boots. His ongoing employment at a shoe repair company has provided him with extensive knowledge on footwear construction and modification. He will also be assisting Clara with the software segment of the project. Louis has experience designing, writing and testing data processing algorithms in C++ and VBA, and is eager to apply that experience to the development of Floe.

4.2 Team Structure Pinnacle Biometrics has adopted the flat structure for management, as it is acceptable

for its team of four. Eliminating the layers of management allows for more effective and efficient communication. This flat structure is very adaptable and does not restrict the team as a more hierarchical structure would. With the overlap of diverse expertise, no part of the project falls behind schedule below its standard of quality. The flat structure allows everyone to freely innovate and come up with creative solutions to the problems that will

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arise. Furthermore, it allows for disputes to be settled with negotiation and reasoning between the members.

Two weekly team meetings have been scheduled to go over progress, outline what needs to come next, and bring up any topics that need to be discussed between all of the leaders. Google Drive is being used to maintain the file repository and allow simultaneous access to all documentation between all members.

5 Project Planning The task breakdown of the project is shown in Figure 5.1. Here, one can find the project goals and estimated duration required for achievement. Progress will be made concurrently on all aspects of the design where possible. Major project milestones are displayed in Figure 5.2.

Figure 5.1 Project breakdown Gantt chart

Figure 5.2 Project milestone chart

01/16 01/26 02/05 02/15 02/25 03/06 03/16 03/26 04/05

Research for Feedback Algorithms

Project Proposal

Order / Receive Parts

Power and Signal Conditioning Circuitry

Functional Specification

Develop Feeback Algorithms

Design Specification

Develop Mobile GUI

Develop Snow2 GUI

Develop BLE Point to Point Com.

Develop BLE Network Com.

Testing and Integration

Post-Mortem

February 1 Hardware parts arrived

February 28 First prototype completed –

single boot and mobile application

March 13 Integration of second boot and Snow2 application completed for testing on slopes

March 27 Fully developed, fine-

tuning commences

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6 Cost Considerations

6.1 Budget A great deal of forethought and rationale has gone into choosing the materials that we

will use to manufacture our product. A bill of materials and their costs can be found below in Table 6.1.

Table 6.1 - Bi l l of materials

Item Description Quantity Unit Cost Total Cost

Bluetooth Low Energy SoC (nRF52-DK) 2 $115.00 $230.00

Piezoelectric FSR (Flexiforce A201) 16 $21.25 $340.00

Recon Instruments Snow2 1 $580.00 $580.00

Power Electronics 1 $50.00 $50.00

Signal Conditioning 1 $20.00 $20.00

Circuit Components 1 $10.00 $10.00

Physical Housing 1 $10.00 $10.00

20% Contingency $248.00

Total Budget $1488.00

The BLE SoC that we decided to use from Nordic Semiconductor is a cutting edge professional chip that will allow us to develop a compact, elegant prototype. This SoC comes provided with development software and an API for the Bluetooth LE communication, and this chip is what we would use in our final product that we would go to market with. This means we will not have to redevelop all of our firmware and software when we transition from prototype to finished product. There are other benefits of using a discrete SoC such as size and energy savings that are beneficial for a mobile battery operated product.

The sensors in our device are critical to the operation of the product, as they will accurately have to track the center of pressure of each foot. Standard FSRs only have a weight rating of 22 lbs. The sensors we have chosen are manufactured by Tekscan, a company who produces many other biomedical sensors, and are piezoelectric sensors with an accuracy and linearity of 3%. Furthermore, they are rated for a weight of 100 lbs, and can be increased up to 10x through the use of extra circuit components.

Recon Instruments have already proven that they have a good product for displaying data to athletes unobtrusively. Instead of attempting to design our own product that achieves the same goal, we decided to develop our product on top of this existing solution.

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The other items are small expenses that will occur when building the smaller systems including the power supply for the board, sensor conditioning, and the case enclosing the chip and power supply. The budget also includes a 20% contingency for unspecified costs such as shipping and taxes.

6.2 Funding The core of the funding for our project will come from the ESSEF of the ESSS. The

total amount of this funding is unknown at the writing of this document, but we expect it will not cover our entire budget. We have contacted the companies we are purchasing components from to inquire about their student project sponsorship policies, and are currently in communication with them. The remainder of our costs will be evenly split between the members of our project.

7 Conclusion The relatively new and increasing trend of augmented learning in the athletic market

calls for new, innovative ways of measuring performance. Although cardiovascular metrics can be useful in conditioning environments, center-of-pressure, or balance, metrics are highly useful for skill enhancement. By providing athletes with real-time feedback based on consistent, quantitative data, they will be able to learn and improve their skills at an accelerated rate as well as without the accompaniment of an instructor.

We at Pinnacle Biometrics are a dedicated team that is determined to bring forth a device that can capture objective quantitative data and convert it into useful information for the user in a safe, attractive and effective manner. Our passion for skiing and the technologies involved as well as careful consideration in aspects of project feasibility are what will drive us to meet our project goals.

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References

[1] L. Vanat. (2014, May 17). The International Ski Market [Online]. Available: http://www.isiaski.org/download/20140517_ISIA_Vuokatti_1_presentation_vanat.pdf

[2] Destination British Columbia. (2014, May 12). Tourism Sector Profile: Downhill Skiing/Snowboarding [Online]. Available: http://www.destinationbc.ca/getattachment/Research/Research-by-Activity/All-Sector-Profiles/Downhill-Skiing-Snowboarding-Sector-Profile,-May-2/Tourism-Sector-Profile_DownhillingSkiingSnowboarding_May2014.pdf.aspx

[3] Tourism Whistler Media Room. (2016, January 25). Stats and Facts [Online]. Available: http://media.whistler.com/all-about-whistler/stats-and-facts/

[4] Prevention by Design. (2006, May 3). Evaluation Methods [Online]. Available: http://socrates.berkeley.edu/~pbd/pdfs/Evaluation_Methods.pdf

[5] D. Millsgale. (2005, May 4). The Effects of Augmented Feedback on Skill Learning [Online]. Available: http://www.d.umn.edu/~dmillsla/courses/motorlearning/documents/chapter14.pdf

[6] ActiveReplay. (2016, January 25). TRACE – The Most Advanced Activity Monitor for Action Sports [Online]. Available: https://www.kickstarter.com/projects/activereplay/trace-the-most-advanced-activity-monitor-for-actio/description

[7] C.C. Weiss. (2014, April 14). Yeti Leaps Out in the Open to Track Skiing and Snowboarding [Online]. Available: http://www.gizmag.com/delazify-yeti-tracks-ski-snowboard/30926/

[8] Flaik. (2016, January 25). Flaik [Online]. Available: http://www.flaik.com/

[9] Piq. (2016, January 25). Ski | Piq [Online]. Available: http://www.piq.com/pages/ski

[10] Recon Instruments. (2016, January 25). Recon Snow2 | Ski & Snowboard Goggles | Heads-Up Display [Online]. Available: http://www.reconinstruments.com/products/snow2/

[11] Y. Hsu. (2016 , January 25). SENSEable Shoes | Code Lab [Online]. Available: http://code.arc.cmu.edu/projects/senseable-shoes/

[12] Sensor Products Inc. (2016, January 25). Podiatry | Foot Plate Pressure Sensor [Online]. Available: http://www.sensorprod.com/foot-plate-pressure-sensor.php

[13] Tekscan. (2016, January 25). F-Scan System | Tekscan [Online]. Available: https://www.tekscan.com/products-solutions/systems/f-scan-system