Developing IMU Sensors For Capturing Motion In Sports

IMU sensors are pretty useful because when strapped to the right location and given the right context they can provide very insightful information about an athlete’s (or anyone’s) movements. In this post, we are going to look at a couple of options in the market that allows us to skip the hardware development and jump right into the application development. Feel free to skip to the different sections that interest you:

[ Intro To IMUsmbientlabsNotch SensorNotch Mocap TestCustom Sensors]

Intro To IMUs

In case this is the first time you are hearing about IMU, here’s a brief intro. IMU stands for Inertial Measurement Unit; it is an electronic device that typically has accelerometers, gyroscopes and magnetometers, and it measures its own acceleration, angular rate (or spin rate) and surrounding magnetic field. IMUs are not only used in sports, in fact, it is used in many consumer electronic devices. Our smartphones for one has IMUs for detecting the orientation of the phone and changing the display to portrait or landscape. The IMUs also allows for functions such as undoing texting errors, a spirit level and motion sensor games. If a user carries the phone with them in their pockets most of their waking hours, it can act as a pedometer counting steps and detect when the user is sedentary. For runners who use running apps to track their runs, IMUs enable some apps to track indoor runs and cadence. Sports Engineering Researchers have used smartphones for tracking wheelchair rugby activities and classifying different sporting activities.

As great as the smartphones are with inbuilt IMU, GPS and processing power to give us real-time analysis, we don’t really want to strap an expensive smartphone onto a football player’s calf to monitor their kicking or tape an iPhone to a tennis racket to measure swing metrics. That’s why companies like Qlipp has developed sensors for tennis or Zepp which has sensors for a number of bat-and-ball or swing type sports. Then there are sensors for rowing, running, surfing, mountain biking and more. There are also different sports equipment that has in-built IMU sensors. Like smart balls (basketball, football, cricket ball etc), smart shoes, smart helmets, smart rackets etc, it could go on and on.

But sometimes we might still not find a sensor product on the market that is right for our sports or health application. So we explore the option of developing something on our own. Fortunately, we don’t necessarily have to start from scratch* because these days there are generic IMU sensor platforms that are designed and built for people who want to develop a sensor for a custom application. They often have the standard 9-DOF (degree of freedom) sensor setup and come with software SDK that allows developers to build their own applications for processing and analysing the data. Let’s look at a couple of options below.

[*when I say scratch, I mean getting sensor boards from SparkFun, Adafruit, Seeedstudio, Tindie etc]


mbientlab successfully launched their first Bluetooth IMU sensor on Kickstarter. They pitched it as a development and production platform for wearables with simple API for iOS and Android. There was some simple soldering required when people bought the first product. I didn’t get one from that campaign but I did get a later updated version which they called MetawearRG. What impressed me when I first got it was the size of it – it’s small and compact and I could use it to build/redesign a smart basketball prototype for a client. Then when I started testing it, I found that their API was really easy to use and I could use their sample iOS app to build a custom app for testing within a (reasonably) short time.

Smart Basketball Prototype and Watch app for tracking optimal shots

Since then, they have made many other versions of sensors with:

  • slightly different sensor configurations,
  • options of coin cell or rechargeable lithium battery,
  • accessories such as cases, clips or wristbands,
  • sensor fusion firmware,
  • cloud services, and
  • hubs to manage multiple sensors.
Metawear RG with custom 3d printed sleeve/case (L) and Metamotion (R)

I haven’t had the chance to try everything but I have to say, I have had a good experience using their Metawear and Metamotion sensors to build various proof of concepts and I am still using them for a number of projects. The sensor data can be streamed to your smartphone or logged on the device. In terms of API support, on top of iOS and Android, they have added Python, C, C# and Javascript, so developers can build stuff on various platforms.


Sample/Template Metawear iOS app for testing

Looking at their new website revamp and some recent emails they sent out about new platform developments, they seem to be putting more focus into the allied health space, in particular, measuring range-of-motion (ROM). They are currently beta testing an app called the MetaClinic and it looks like they are using skeleton-tracking the likes of motion capture systems which would probably mean we need to use multiple sensors. That should be interesting.


MetaClinic App by mbientlab

Notch Sensors

Notch also launched on kickstarter, in fact slightly earlier than mbientlabs’ campaign. They had an interesting concept of integrating individual IMUs into custom designed clothing using pockets in discreet locations. Unfortunately, they weren’t successful at that instance. Their initial use case probably wasn’t strong enough. So I guess the founders went back to the drawing board, revamped it all and went with the “motion capture” approach for developers.


Notch sensor with elastic band and clip

With the new design, the shape of the IMU sensor is essentially the same but they have ditched the micro-usb in each IMU for contact pins and made it water-resistant (IP67). They also designed elastic bands of varying lengths with a sensor clip and a user can secure each sensor up to 15 different locations on their body including head, chest, upper arms, wrists, hands, waist, thighs, ankles and feet. So instead of selling individual IMUs, they sell a kit of 6 IMUs with a set of elastic bands, and if a user wants to do a full (body) setup, they will need 3 kits.


The Pioneer Kit: 6 IMUs with charging case and elastic bands with clips.

A quick test and review (for biomechanics)

I had the opportunity to run a short pilot test with one (the pioneer) kit in a biomechanics lab. I used the lower body setup which used all 6 IMUs strapped on my chest, waist, thighs and shins/ankles. In terms of setting up, it was pretty straightforward. After following an initial calibration procedure of all the IMUs in the case, I put on the bands and clipped each IMU to the right location according to the different colours as indicated on the app. The only thing is putting on the bands takes a bit of practice and I had to swing around to check that the bands are not too tight and restricting movement. Even though I don’t have muscly quads, I felt that the bands were somewhat tight and needed adjusting after a while.


Setting up the Notch IMUs for lower body measurements

For testing, I did a simple protocol of walking, stopping and doing 3 squats of varying depths. Then I compared my knee angles measured on the notch and the motion capture system. A few quick things that I took out of the knee angle measurements were:

  • The angle measured by Notch is the exterior angle while the motion capture system looks at the interior angle. So it needs a quick recalculation before comparison.
  • Assuming the motion capture system is the more accurate measurement, Notch had a larger error as squats went deeper.
  • But for walking, the knee angles measured were quite close.

It’s wasn’t a very elaborate test but even from this simple outcome, I can safely say it’s probably not the best tool for accurate joint angle measurements. Although for a quick 3D visual feedback on movements, it might work. Here’s the clip of me doing the test described above (feel free to rotate the video to get different perspectives):

Further to that, I could only download angle data. If I wanted the raw sensor (acceleration and gyro) data, I would need to pay for an extended license that is renewed annually.

In terms of custom development support, they used to have support for iOS but they seem to have taken that off now and only have support for Android which I thought is a bummer. I am guessing they have some issues with getting it right on iOS. Hopefully, it is just temporal and they will resolve it soon. For Android developers, it looks like they have pretty good support and even provides a template app. I have to add that there is a fair bit of fine print I need to agree to before I can get access to their SDK. If I read it right, they basically want a licensing fee for using/commercialising their SDK.

Custom Sensors

Both of the above IMU sensors have similar specifications when it comes to measuring acceleration (using accelerometers) and angular velocity (using gyroscopes). The typical measurement range for accelerometers is +/-16g (that’s 16 times of gravitational acceleration), and for gyroscopes, it’s +/- 2000 degrees per sec. For many applications, this configuration is fine. But there might be some cases where higher acceleration needs to be measured and that goes beyond 16g, like shocks or high impact collisions. Or I might need high-speed rotations to be tracked and 2000 degrees per sec is too low, like measuring the spin of a cricket ball or gridiron football (which can come close to 3600 degrees per sec or 600rpm as demonstrated here by Drew Brees).


Spin rates of a gridiron football during a throw test

As briefly mentioned earlier, hobby electronics stores like SparkFun, Adafruit, or Tindie would be a good place to start when looking for accelerometers and gyroscopes of different specifications. There are also lots of microcontrollers with Bluetooth Low Energy (BLE)  built-in that are Arduino compatible so we can program them with the Arduino software. One that I found pretty handy is this one called Blueduino which comes with a Lipo charger add-on (and add-ons are great) and that can be found on Tindie.

Football sensor

The gridiron football sensor prototype using the Blueduino

Final Word

For those who are in research and possibly need Matlab and software support for building custom Matlab programs, definitely check out Sabel Sense sensors (Australia). Else, I reckon the mbientlab sensors would be a great option for starting a custom development. If I get a chance to trial their Metaclinic platform, I will put up another post. Meanwhile, do drop me a message here if you need assistance or advice in any of the options above and feel free to leave a comment if you know of better/different solutions out there. With that, thanks for reading!

Accelerating Sports Technology Development And Innovation

Roughly 4 years ago, I wrote a post about crowdsourcing sports innovation – how sports companies and organisations were inviting people with ideas to step forward and pitch their innovations. Fast forward to 2017, the ways of generating new sports tech ideas have grown and evolved. From sports hackathons to accelerators, incubators, and Meetups, and online communities and invite-only/secret-squirrel investment funds or a mash-up of 2 or more of the above.  I am definitely no expert in this area but based on my very limited experience, here’s a look at a few of the possible ways to accelerate sports technology development and innovation.

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One way of defining hackathons* (from HackathonAustralia) is this: “Hackathons are competitions that challenge people to create something over a set time period using technologies.”. So in the case of a sports hackathon, that “something” created would be an innovative sports tech solution that meets an existing need/pain. It could be a hardware solution or a software solution or both.

[Themes] Depending who is organising or sponsoring the hackathon, events could have a specific theme/focus like the Western Bulldogs hackathon that provided participants with their athletes’ GPS data to do further analysis or the Future Of Sports Tech Hackathon by Enflux that allowed participants to use their motion capture technology or the Hack4Sports that had a focus on building sports tech startups.

[Needs Assessment] Whichever the theme, the participants would require some guidance/directions on real needs vs good-to-haves. That’s where industry experts and end-users (sports clinicians/analysts/coaches etc) who are at the event, can offer that perspective. This could be through talks or interactive workshops on specific areas such as improving performance or injury prevention or increasing participation etc.

[Forming teams] Following that, teams need to be formed to design the solutions. Some participants might have already formed teams prior to signing up to hackathons. But it is quite common for people to rock up by themselves. So hackathons might dedicate a session for team-forming. Typically people who have a passion in the same area would team up. Other than that, it is also helpful to have a good mix of hackers, hipsters and hustlers in the team.


Hustler, Hipster and Hacker

[Pitching Comp] Most hackathons involve a pitching competition which means the solution (created within that 1 or 2 days of hacking) has to be validated with real life users/customers and has a potential market fit. The team with the winning pitch usually wins something that can help them take their idea further. That could be prize money or often they get to be part of an accelerator program to develop that Lo-fi prototype into a minimum viable product (MVP). Else they at least have bragging rights.

[If you are interested in a sports hackathon, please complete this SURVEY]


Sports Tech Meetups (literally on the Meetup site) are to some extent scaled down versions of hackathons and/or pitching competitions. It is usually a local group of sports tech-minded people getting together once in a while to do stuff such as pitch nights or show-and-tell or have people already in the industry sharing their insights and experience. There are no fixed rules and format which makes it quite casual and there are no barriers to joining a meetup other than geography. All you need is an interest in sports technology.

[Here’s a couple of examples: Melbourne Sports Analytics Meetup, Seattle Sports Tech Meetup]

This makes Meetups a good platform for people who are new to sports tech to come explore the field, network and learn more.  It is also good for people who have developed a concept or MVP to come and get feedback from others (through pitch nights or show-and-tells). The next steps for these people could be to take part in a hackathon or join an accelerator program or incubator.


Online Communities

I believe this is quite plain and doesn’t require much explanation. There are quite a number of online platforms that allow people with an interest or a stake in sports technology to be a part of. From Google Groups to LinkedIn Groups to Facebook Pages. But what I observed (at least on LinkedIn Groups) is that there are very little open discussions within the groups/pages. In most cases, article posts get “Likes” or 1 or 2 Comments. Sometimes the posts are just companies trying to promote their products and services which often gets no “Reactions” whatsoever. So I am not sure if these groups are any good at promoting or even accelerating innovations in sports tech.

There is another online platform that has been growing in popularity (in the last few years) especially in the startup community – it is an invite only platform called Slack. Basically, it is meant to be an internal chat system for team members of an organisation to have work/project discussions. But one sports technology startup group that call themselves Starters decided to jump on this platform and allowed anyone who is in a sports tech startup (or trying to build one) to sign up to be part of the group. Though there is a fee to get in, it’s mostly to ensure that only people who are seriously interested join.

Screen Shot 2017-04-10 at 9.24.07 PM

But what is happening within this Starters Slack group is quite phenomenal. Ideas are exchanged, there are open discussions, Ask Me Anything (AMA) sessions, connections and introductions are made online, followed with meet-ups in real life, actual events (hackathons, accelerator programs & meetups) are organised and promoted, and I am sure there is more happening between individuals through direct messages (DMs). What’s amazing is that though it’s mainly based in the US, there are individuals and companies participating from all over the world.

Screen Shot 2017-04-10 at 6.14.18 PM

Starters – a global sports tech startup community

Slightly similar to Starters is a SportsBiz slack group started by the SportsGeek from Melbourne.The main difference is that there is slightly less emphasis on startups or sports technology and more on sports business in general. But the objective is not that different – to use the platform for sharing ideas, finding collaborators and opportunities, and ultimately pushing the sports industry forward.

Screen Shot 2017-04-10 at 9.40.01 PM

Some Key Points

So there are a few key points that I take out of this. One of it is, we need to collaborate. No one can build anything great on their own. Not only do we need a diverse team with different skill sets, we need input from other people (locally & globally) or run the risk of tunnel vision. Secondly, competition spurs innovation. Which is quite apt since we are talking about sports technology here, where one of the aims of it is to help athletes perform better and win the competition. Lastly, none of the avenues on its own can be the be-all, end-all of this topic. Especially if we are talking about building successful long-term sports tech enterprises. People at different stages of their ideas or development would probably go through a different process. What may work for some may not work for others. We may need to change from something that doesn’t work anymore (e.g. LinkedIn Groups) to something else that does (e.g. Slack).

I know I haven’t commented much about accelerators and incubators. That’s mainly because I have not had any personal experience with them. What I do know is that you need to at least have a team (and not just a great idea) to be part of an accelerator and preferably an MVP to join an incubator.

Finally, I think for someone who: has a few good ideas, is passionate about  (or has some exposure to) sports technology and doesn’t quite have a clear direction or built a team yet, a sports hackathon can be a good place to start. This is something I would like to explore a little more. So if you think the same way and would like to take part in a sports hackathon (or not), or if you have other thoughts on accelerating sports technology innovation, do help me out and complete this SURVEY or leave a comment or drop me a message on Twitter or LinkedIn. With that, thanks for reading!

This post can also be found here

*Hackathons have also been known as hack days, hackfests, startup weekends, makeathons, design-athons etc.

Versus Fitness: Developing A Smart Gym

VersusOver a year ago, I wrote a post about developing with the Kinect and how I was working on a project that revolved around it. Fast forward to today, the project is now an officially launched gym that is also known as Versus Fitness.

What is Versus Fitness?

Versus is a system that has gamified fitness. By utilising different sensors and technologies, it is able to measure 3D motion, pressure, force, acceleration and power output of over 200 different gym exercises (and counting). With each proper repetition (or rep) that is executed, the user not only gets the rep counted by the system, a score is given based on the above measured parameters, and the score is scaled based on the user’s weight and height. In that way, 2 people of different weight and height doing the same workout can compete against each other on almost equal terms (Hence the name Versus). In case the term “wearable technology” comes to mind, no, there is nothing that the users need to wear to get their exercise tracked (maybe except a heart rate monitor, but that is purely optional). Just check out the video below.

How I got involved?

I started working on the Versus Fitness gym since late 2013 and it was purely by coincidence. Someone who knew Brad Bond (the founder of Versus Fitness) was at the RMIT Sports Engineering Lab on one of those Uni open days and he saw a novel sensor technology that would suit Versus. After a series of meetings and discussions, a research contract was set up to further develop that technology for Versus. This was partly funded by the Victorian Technology Development Voucher. At the same time, they were also looking for an additional team member to work on motion tracking algorithms. That’s where I came into the picture. Long story short I was offered a contract role on the Versus project which was partly funded by the Enterprise Connect – Researchers in Business grant (this has been replaced by the Entrepreneurs Infrastructure Programme). Kudos to Aaron Belbasis who was a key connector/initiator who brought everyone together and who was also one of the key researcher who helped develop the novel sensor tech. There’s a bit more details about the RMIT-Versus collaboration here.

What Tech are we talking about here?

One of the sensor technologies came from the research collaboration mentioned earlier. The team at RMIT calls it a “sensor-less sensing platform”. The closest thing would be Force Sensitive Resistors (FSR) like the ones from Tekscan. If you had a proper look at the video above, you will see the “sensor-less sensing platform” used in the floor exercises and some of the running exercises. Basically its a sensor that measures pressure.

There are other sensors that were developed or customised for tracking motion and a number of them are available off the shelf or at least purchasable online. In fact some of the sensors (like load cells and accelerometers) are similar ones typically used in the manufacturing, or automotive industry. A lot of custom fittings, enclosures and mechanisms were designed for the sensors before they could be installed in the gym. Majority of the design were done in-house and prototyped with the help of a MakerBot replicator.

But what really made the sensors (tracking system) worked effectively are the smart algorithms that processes all the sensor data and accurately identifies when each person is performing the exercise properly and evaluates how well he/she has done it. Initially when designing the algorithms for tracking each type of exercise, it all seemed pretty straightforward; but as things progressed, it turned out there were quite a few more considerations – e.g. filtering out “incorrect” movement data that resembled an actual rep, or profiling movement data from users of different abilities (or fitness level) etc.

Perception & Reality

Another important part of the system is the “gaming interface” or the “gaming control centre”. It is the personal trainer’s assistant. It relays to the users what exercises to do, records their performance, stores the performance data in a database, reminds the user how well they did previously (their Personal Best), manages the equipment (to some extent), and ensures that every exercise station is in sync so that the workout runs smoothly. That allows trainers to focus on one of the things they do best: scream at motivate people.

So with the combination of the sensors, smart algorithms and the gaming interface, this means: real-time tracking, with feedback of the users’ performance (score) or technique delivered right after each completed rep, and an overall quantified workout so users know how well they fare compared to their previous workouts (and with other users).

Future Developments?

The very first Versus Fitness gym is based in Moorabbin and that has seven different exercise stations (as seen in the video above). One could call that the full Versus experience. There are a number of possible developments in the pipeline. One is the development of new exercise stations to increase the type of exercises that can be tracked. Also, there are possible opportunities to customise the system for the elite or professional athletes, or even rehabilitation applications. Something that is definitely in the works is a “multi-station” concept – a single exercise station that has several sensor solutions allowing tracking of a few different types of exercises (e.g. dumbbell, kettlebell & floor exercises). This significantly reduces the footprint of the equipment and would suit small gym spaces. In fact this is currently on trial in a gym somewhere in Australia, and depending on how things go, you might start finding the VS logo in many more places!

Developing with Kinect sensors for fitness and health

microsoft_kinect_sensorThe Kinect sensor has been widely used (hacked/developed/applied) by many ever since the Xbox 360 was first released. A couple of years ago, a fellow sports engineer from SHU studied the feasibility of using the Kinect sensor as a biomechanical analysis tool. He concluded that although the Kinect was fairly accurate, it wasn’t good enough for serious analysis (You can read more in his blog post here). The main advantage of the Kinect was (and still is) it’s price compared to professional motion sensors, and the Microsoft SDK which allows developers to come up with interesting applications (Check out various kinect hacks here).

I recently started working on a project that utilises the Kinect sensor. The project is basically developing a fitness product/system that combines the use of various sensors for assessing gym exercises. It is a rather interesting and novel concept because not only does the product quantify different gym workouts, it has a gamification portion where each user is competing with another gym user at the same time. No, it’s not like online gaming. In fact, this system is not designed to be used at home, but rather in a gym setting where participants perform the workouts together and get scored at the end of each session. Think Nike+ Kinect Training but for many people physically at the same place and with smart gym equipment (Equipment with sensors and smart algorithms). I probably should not go into too much details to avoid spoilers, but do look out for it’s launch sometime this year!

Nike+ Kinect Assessment

Nike+ Kinect Assessment

Anyway, I had the opportunity to test out the Nike+ Kinect Training (NKT) and found that it has quite a well designed interface that helps the user perform workouts with proper techniques. For example, the Kinect (ver 1) sensor is not the most accurate in measuring depth, so for exercises like push-ups, burpees, and core exercises like the bird-dog, the NKT gets users to turn to the side instead of face the TV/Kinect sensor; that way, the user’s movements are tracked more accurately. The concept of the NKT program is also pretty good because it starts with putting the user through an assessment – a series of movement tests and exercises, then rates the user in terms of strength, flexibility and stamina. Following that, it recommends a scheduled training program with a combination of exercises that can help you reach your goal (either to build power, become toned or lean). The feedback given by the on-screen personal trainer are usually quite spot on, usually correcting my posture, asking me to slow down (for exercises that are meant to be controlled) or speed up (for endurance type exercises), or just encouraging me to push on for the last few reps. There are instances where the Kinect sensor was unable to track some of my joints accurately and failed to count my reps, especially in a few of the floor exercises. But all in all, it is a pretty good program based on some sports science fundamentals and it could be an effective training tool for people who like to workout alone. I also got some good ideas off it that might be useful in the project I am working on.

{On a separate note, there has been some interesting devices/gadgets developed for the fitness and strength training folks in the last few months:

  • PUSH – a wearable arm band (possibly built with inertia sensors) that is able to determine force, velocity and power of each strength training rep
  • Hexoskin – another wearable smart apparel that not only measures movement (activity level, steps, cadence), but also the users physiology (heart rate and breathing rate).
  • Athos – similar to the Hexoskin, it is a wearable smart apparel with the addition of electromyography (EMG) capabilities embedded in the apparel.
  • Skulpt Aim – a mobile device that measures the user’s body fat percentage and muscle quality in individual muscles.

These devices (and other smart devices) could potentially become a common sight in gyms in the near future, allowing users to track more about their workout sessions and gain more understanding of what’s happening. A common trait among these gadgets is that they all have (or are developing) iPhone apps, which means users will have access to their workout history on their fingertips and probably be able to brag about it on social media.}

Going back to the Kinect sensor, apart from sports and fitness applications, developers have also come up with practical solutions for the medical and health industry. One such application is the Teki system developed by technology services company Accenture, and a few other partners including Microsoft. The main purpose of the Teki system is to reduce the need for elderly patients to travel to the hospital for routine consultations and check-ups, saving time and money. Using a Kinect sensor, set up at the elderly patient’s home, together with a few other wireless medical devices like a pulse oximeter and a spirometer, the doctor is able to do a remote consultation using a webcam in the hospital/clinic. The Kinect sensor comes in when the doctor needs to evaluate the patient’s range of motion; or when there are prescribed rehabilitative exercises that the patient need to perform and the Kinect sensor is able to assess and provide feedback to assist the patient.

Kinect v2

Kinect v2

It was mentioned earlier that the Kinect sensor isn’t the most precise in measuring movements, especially in terms of depth and also higher speed motions. Although the specification says that it could measure up to 30 fps, but after testing it myself, I found that it is usually around 15-16 fps (depending on your program). Lighting and certain background objects could also affect the detection of a full skeleton. But all these little ‘glitches’ will no longer be there with the release of the new Kinect 2 sensor which features improved performance over the original Kinect. Those improvements include: a wide-angle time-of-flight (ToF) camera allowing better range (or depth) measurements; capturing 1080p video, and ability to ‘see’ in the dark with its new active IR sensor; it can detect more joints on the body (5 more than the previous) with much higher accuracy, and it can track up to 6 skeletons at one time. Also, it is capable of measuring the users’ heart rate via a change in the user’s skin tone and even detecting mood from the user’s facial expression. {Just watch this video that basically demos all the improvements.}

With this newer Kinect sensor, it will be a lot more exciting for hackers/developers and who knows what interesting applications could be invented. But as of now, there is still no news of when Microsoft will officially release the windows version of Kinect 2 for developers; for those who are really keen, there is a preview program with limited spots that you can apply for here!

If you know any other Kinect applications in sports and health, feel free to comment below. Thanks for reading and here’s wishing everyone a happy new year!

Designing an iPad Cooling Case

A while back, I was referred to someone who had an issue with overheating iPads (the 3rd gen one). Due to the nature of his work (coaching/sports science), he often uses the iPad under the sun, which contributes a fair amount of heat to the iPad, and it was overheating to the extent that it would shut down. The shutting down was meant to be a safety feature to prevent it from blowing up, but this became a huge inconvenience for him. So the challenge for me was to come up with a solution to cool down the iPad so that he can continue using it under the sun.


Overheating iPadFirst I did a bit of research on the internet, and found that the new iPad (3rd gen) did have an issue with overheating. An article from Reuters even found that the iPad racked up temperatures of up to 47 deg Celsius after 45 minutes of running an intense action game. It didn’t bother most people (from what I read on the forums) because they will just stop using the iPad when it got too warm and let it cool down, or use it on the table instead of holding it with their hands. But for someone who needs to use the iPad as a sports training tool under the sun, it was a problem.


Next I explored the possible options for cooling the iPad:

  1. Cooling with water – People who overclock their PCs are usually the ones who would try using a water cooling system. You could build one on your own, or buy a system off the shelf. It will work for a PC, but an iPad? I am not too sure. I think one thing for sure is it will make the iPad way too bulky.
  2. Using an ice pack – Anything that is zero degrees should cool things down. But, the thing is, it will also cause condensation. There will be water droplets everywhere, your hands gets slippery and oops, you drop the iPad on the ground. Not a good idea.
  3. Heat sink – Heat sinks are only effective if there is complete contact between the hot surface and the heat sink; and typically that is achieved by applying heat sink compound or thermal paste between the surfaces. Also sticking a couple of heat sinks at the back of the iPad might make it less ergonomic to carry.
  4. Cooling fans – Now this might work. All we need is somewhere to mount the fans, allow the air to move around the back of the iPad and carry the heat off the surface.


Out of the 4 options, I picked the cooling fans since it seemed the most feasible solution. My initial plan was to build a 3D model and run a CFD simulation to test out the concept. But when I started to draft something on SolidWorks, I ended up designing an iPad case which could house two 10mm fans and with channels for directing air across the back of an iPad. Then since I had access to 3D printing,  I decided to just build the prototype, get two 10mm fans and ran an actual test with the iPad. 

1st prototype with fans

1st prototype with fans

On one of the few sunny days in autumn, I borrowed a 3rd gen iPad and subjected it to some ‘heating’. I turned on the iPad, stuck a thermocouple on it’s back and left it under the sun. It was about 30 deg C that day. Once the thermocouple reading reached 45 deg C, I inserted the iPad into the prototype case and turned on the fans, while leaving it under direct sunlight. The good news was that the temperature dropped by 5 deg only after a minute or two with the fans on. But rate of cooling slowed down after that and it dropped to 34 deg C after 20 minutes. 34 deg C is still quite warm but since this is still under direct sunlight, and it was a 30 deg C day, I would say it was quite effective.


In my opinion, the concept worked. The design just needs a bit of tweaking. Firstly, I didn’t get the dimensions of the iPad right so the case didn’t really fit that well. Secondly, I picked the wrong fans – they were a little too big and they needed a 12V supply. Thirdly, the fans had to be switched on manually – it would be better if there was a temperature controlled switch.

So I got all those sorted out:

  • Improved the case design. Even added a slot to mount a wide angle lens for the rear IMG_2388camera.
  • Found smaller fans that only required 5V power supply.
  • Also got some help with building a temperature sensor circuit that will switch on the fans when it gets too hot (it’s adjustable via a variable resistor).


Before I went ahead to build a second prototype, I decided to find out how much it would actually cost to 3D print it (The first prototype I got was given to me in kind). To my surprise, it would cost over $600. It would actually be a hundred dollars cheaper to have the case prototyped using CNC machining. On the other hand, all those electronic components plus the fans would only cost less than $20.

Well, if I was making a few thousand of those cases, I could just design moulds and get those parts extruded which would then bring down the cost of each iPad case. But how many people will actually need a cooling case for their iPad??

Also when I was working of this project (back in April), there was already the 4th gen iPad in the market, which was kind of an improvement. There were still complains of the iPad 4 being too warm, but I was thinking, it wouldn’t be long before Apple came up with a newer model that will totally solve the heat issue. Fast forward to today, out comes the iPad Air with a brand new processor! Apple has also stopped manufacturing the 3rd and 4th generation iPads. That’s probably because they realised they were inferior designs!


Although I didn’t get to mass produce these iPad cooling cases, it was overall a good experience. I realised that I would have to work faster if I wanted to make accessories for tablets or smart phones because a newer and better version is always coming out. Also the cost of commercial 3D printing services is way too high. If I wanted to get 3 prototype cases built, I will be better off buying myself a 3D printer. The cost of thermoplastics for printing doesn’t seem too expensive. Might be cheaper than traditional ink cartridges!

Anyway, thanks for reading, and if you think this iPad cooling case is a good idea and you want to get one, leave me a message!

Crowdsourcing Sports Innovation

Crowdsourcing Sports Innovation GameChangerMost people probably heard of crowdsourced funding platforms like Kickstarter or Indiegogo. There are of course many other similar platforms all over the world that help budding entrepreneurs or generally people with new/good ideas to fulfil their venture. I wrote a little about crowdsourced funding for sports technology a year ago and since then, there has been a LOT more innovative sports tech products that went the crowdsourced funding way. Some of them were also mentioned on this blog, like wearable activity trackers,  swimming technologies, smart sports equipment with sensors and tech that prevents sports injuries. Like I said, there are LOTS more sports technology that are on those platforms and I reckon Kickstarter or Indiegogo should just start a new category called Sports Technology. If you follow DCRainmaker, you will probably notice that he has set aside a section for athletic crowdfunded projects on his weekly reviews.

Now, it sounds like its just the sports innovators and entrepreneurs putting themselves out there, seeking random funding and investors, but things are starting to change.

The Australian Sports Technology Network recently ran a Sports Tech Investment Pitching Competition (2nd year running) that aimed to uncover new innovations in sports technology. How did it work? Basically, people were invited to make an initial submission of their product/innovation; then 8 of the submissions were selected and put through an eight minute investment pitching competition where each of them were ‘grilled’ by experts in sports business and commercialisation (think Dragons’ Den). Finally a winner and a runners up were selected based on innovation and commercial viability. On top of winning some prize money, they also receive 12 months of advice and mentoring to assist them in their new venture. If you want to see what one of the ASTN pitching is like, check out this video from the 2012 competition:

Nike is running their own innovation program starting early next year (also for a second time). Focused around the Nike+ fuel band, Nike launched the Nike Fuel Lab. So if you have an idea of a product or service that could integrate with Nike Fuel (and “help millions of people be more active”), Nike is inviting you to submit your idea by 20th Jan 2014 (no business plans required). 10 of those submitted ideas will then be selected for a 12-week program (in San Francisco) where the 10 teams will be given access to the Nike+ APIs and SDKs, and coached to further develop theirs products/services technically as well as from a business point of view. Finally at the end of the 12-weeks, a Demo Day will give the ten teams an opportunity to present their product concepts to the Nike leaders, industry leaders, angel investors and venture capitalists. To get a rough idea of how it’s like, check out the below video of their inaugural program called Nike+ Accelerator that just ended a few months back.

Under Armour (UA) is also crowdsourcing innovative ideas that leverages on their new performance monitoring device – the Armour39, which is essentially a heart rate monitor strap with connectivity to an iOS device. As far as I can see, there are no motion sensors in there but it does calculate calories burned and a metric they call WILLpower (trademarked). The format of their competition, the Armour39 challenge, is quite similar to the ASTN and Nike one. Innovators are invited to submit proposals for technologies that could expand the capabilities of the Armour39; all the proposals will be sifted down to 50, and those 50 get to develop their prototypes with the Armour39 SDK; then 15 of those prototypes get selected to do a final presentation/pitching on this Digital Future Show event next year (which is also only their 2nd one). Winner and runners up get the prize money and the opportunity to collaborate with UA. Here’s a glimpse of what the last Future Show was like and what were some of the ideas that surfaced:

I think by now we all get a gist of what’s going on here, my point is, sports companies and organisations are starting to look for innovations outside of themselves. They obviously recognise that they don’t have all the answers (even with their engineers and scientists working hard in the labs) and they probably noticed that there are many innovators/creators/makers out there with ideas but not enough resources to bring it to fruition. So they start their own crowdsourcing – Set up a stage/platform to draw innovations in, pick out the good ones (ones that can make money), invest in them and push them into market! Sure, its not a new concept and they sound like a spoof of Dragons’ Den (or other programs..) but its churning out sports innovations and I think that’s awesome!

Lastly, for those of you who have innovative ideas for technology in sports, why not give these competitions a shot. The ASTN pitching competition will probably run again next year, check out their website for details*. The Nike+ Fuel Lab has a submission deadline on 20th Jan 2014 and the deadline for the UA Armour39 challenge is 15 Nov 2013. Even if you don’t win the competition, I reckon you still gain some interesting experience. Or if you are not one who likes to “show off” in public, Under Armour also set up an online tool for people to submit their ideas, and they will work with you to develop it if they find it has potential. So what are you waiting for? Like what the 10th Doctor always says: Allons-y!

*the ASTN pitching competition is currently only open to people living in Australia.

Safety Technology in Sports

Safety Technology Shit Accidents happen. Nobody plans for them to happen. But they do. The thought of “what if…” can be quite frightening, especially for people with some form of anxiety disorder. So if you are going for an overseas holiday, you might take up a travel insurance; if you are a school teacher bringing kids out for an excursion, you might prepare a risk management plan before that; and if you are organising a football competition, you will want to ensure that you got first aiders or sports trainers during the game. For protection, athletes wear safety equipment such as helmets, mouth guards, body armour, braces, goggles, gloves etc to reduce the risk of injury and possibly death. But if one considers the theory of risk homeostasis, athletes may go harder or play with less caution because of the protective gear and thus negates the effect. Lately engineers/designers/innovators have resorted to using various sensor and wireless technologies to help manage or prevent serious injuries in sport. We will have a look at a couple of these technologies that have been developed.

Managing concussions


Riddell’s built-in sensors

Wearing helmets are only good for protecting against skull fractures but not brain concussions. The next best thing to do is to measure the amount of impact and deduce if that might cause a concussion. The first helmet with a comprehensive impact detection system was Riddell. The Riddell HITS technology helmet is embedded with multiple sensors that measure the magnitude and direction of impacts to a player’s head. The impact data is transmitted wirelessly to a computer at the bench where it is analysed to determine the likelihood that the player has a concussion. This helps coaches and medical staff decide whether or not to take a player out of a game or the next few games.

After Riddell, a couple other companies like Brain sentry and Shockbox came up with (cheaper and) more versatile solutions. Basically, they developed wireless sensor devices that can be mounted on your own sports helmet (whether it’s Gridiron, Hockey, Lacrosse, Snow sports etc). The Brain sentry sensor works by flashing a red light when an impact over a certain threshold is detected, and that is an indication that the player should get some medical attention – a simple and straightforward system. The Shockbox sensor sends out impact data directly to the coach’s smart phone via bluetooth and the smart phone app allows the coach to monitor all the athletes at once for dangerous hits. How do they decide what amount of ‘g’ is too much? Well research by Greenwald et al and Broglio et al showed that most concussions happen between 70-100g, so any impact above 70g => possible concussion. HelmetSensors There are a  few other head impact sensors that work on a similar concept but worn slightly differently (on/in the head). The i1 Biometrics Impact Intelligence System is a mouthguard with built-in sensors, while the Impact Indicator 2.0 is a chin strap also designed with sensors that measures high accelerations. One thing worthy to note about the i1 Biometrics mouthguard is their shock absorbing material Vistamaxx that is also customisable to every athlete’s mouth.

ImpactDetection2If you google “head concussion sensors”, you will find a few other similar products that is entering the market soon. The bottom line is, they all identify impacts that are over the “safe threshold” and athletes can be kept (safe) on the bench instead of getting a second hit which could be deadly. But to really know if an athlete had a concussion, they still need to have a CT scan or use this electromagnetic coil that is a cheap substitute.

Preventing drowning

There is a shocking number of people who die or become permanently disabled because of drowning. Even with lifeguards or in cases where children are playing in the water with adult supervision, drowning could still happen. That’s because it only takes 20 seconds for a child to drown underwater unnoticed and 1 minute for an adult. Which brings forth the need for drowning prevention technology.

Aqauatic Safety Concepts LLC patented an Electronic swimmer monitoring system that consist of wearable sensors (worn on swimmers) that measures time of submersion and a monitoring system  at the pool or lake that detects drowning risks and alerts the lifeguards on duty.


The wearable sensor can be worn as a headband or attached to a swimmer’s goggles or swimming cap. The sensors send out a distress signal when submersion is past a safety limit, the signal is picked up by highly sensitive Hydrophone Receivers mounted in the lake or pool which then translates to an audio and visual alarm on land alerting lifeguards or  pool supervisors. In lakes or ponds where the water is not clear, a mobile receiver or Swimmer Locator can be used by the lifeguard to quickly find the distressed swimmer. A Control Tablet can also be used by the lifeguard to monitor status of swimmers in the facility.

But for folks who have a small home pool and don’t need such an elaborate system, there are a couple of choices for small portable systems, like the Safety Turtle and the SEAL Swim Safe. Both work on a rather similar concept: swimmer wears a wearable sensor that detects submersion and is monitored by a portable base station that runs on batteries.They both also use names of sea animals! Apart from that, they are actually quite different with two main differences:

  1. The Safety Turtle sensor is a wearable wrist band whereas the SEAL is a wearable neck band.
  2. Safety Turtle developed separate systems/devices for adults and pets; while the SEAL designed four different safety levels on the band, starting from an immersion alarm for the non-swimmer to a more complex triggering mechanism/algorithm for safeguarding elite swimmers.

DrowningDetectionTechWhen asked why the neck band design was used for the SEAL (which on first glance appears to be an awkward swimming accessory), the CEO and Co-inventor, Dr Graham Snyder said the sensor/antenna had to be in close proximity of the nose and mouth for the detection to be accurate; and tests with swimmers confirmed that having it at their neck was not as noticeable as they thought nor did it restrict swimming.

In fact, because the SEAL was designed to be used by swimmers of different abilities, one of the biggest challenge the developers had was preventing false alarms in every safety level and making sure that drowning detection is highly accurate and timely. Going forward, the team that brought out SEAL is also planning to add other features including GPS, two way communication and monitoring physiological parameters.

Even with all these terrific wireless sensor technologies developed for keeping sports safe,   the most critical component is still human intervention – coaches and medical staff to identify a possible concussion, and vigilant lifeguards and parents to note dangers and distress in swimmers. Without them those technology will just be another piece of accessory.

Thanks for reading and stay safe!

Crowd sourced funding for sports equipment

The smart watch with an embedded accelerometer and wireless communication with iOS devices.

A couple of weeks back, the Australian Sports Technology Network had their inaugural conference and it was a huge success. Very well attended by people in the industry, there were very interesting talks and discussions with views from various perspectives. Anyway there’s a great summary of the event here. What was less known was the Sports

Technology Innovation Bootcamp that took place a day before the conference. It was the first ever bootcamp that was focused on sports technology innovation, commercialisation and entrepreneurship. I am not going into too much details about it, but at some point during the conversations, someone brought up ‘kickstarter‘, which is a rather popular online platform for sharing creative inventions with the community and asking for (financial) backing. In other words, crowd sourced funding. Put simply, if I have a great product idea and a working prototype, and I need more money to mass produce it, I then make a video telling everyone how awesome my product is, why they should ‘back’ it, and what (reward) they would get out if they do. The reward is usually the first batch of the mass manufactured product. Its a great concept and there has been many successful design and technology products that were launched from this platform. Quite a number of them being sports technology related projects.

There are however a couple of disadvantages to this method of getting funding. Firstly, your idea could get ‘stolen’ or copied, especially if no IP is involved. Did a quick search and I found a lot of ‘same-same but different’ ideas that were funded on kickstarter, like these: revolightsFiks & Nori Lights. Secondly, other than getting money to take the product to market, you or your team are pretty much on your own to: first, deliver the reward (on time), then take the business to the next level, which can be a daunting task if you don’t have any prior business experience. That’s where angel investors (whose been there and done that and has the resources) do better. Not only do they provide the financial backing, they can provide the mentoring to make the venture and the entrepreneurs a success; that is assuming there was an innovative and commercially viable idea to begin with.

In saying that, crowdsource funding sites like kickstarter does have its appeals – it has lower barrier to entry, promotes use of social media, marketing by word of mouth, it reaches a global community, and there is a general sense of excitement that is shared by everyone involved. But if you are in Australia and you have a fantastic (and marketable) idea for a sports equipment or technology, you should definitely contact the guys at the ASTN or ASTV who basically have the capabilities of angel investors and they also have a strong network in the local and global sporting industry.

Its too bad that I don’t have any brilliant sports technology ideas (for now), so most of the time I am just checking out interesting projects on kickstarter, hoping to get inspired, but usually I only end up being tempted to back some of them. Fortunately I have managed to refrain myself most of the time, except the one time I backed this amazing sports watch. Still waiting for it to be delivered though. Hopefully it will arrive before Christmas. In the meantime, I leave you with these two great projects that are still open to more backers:

The Oru Kayak

Specta Cam