Review: Qlipp tennis sensor
Qlipp Tennis Sensor
- Great app
- Granularity of stats is extremely impressive
- Works with any tennis racket
- Connects to the Apple Watch for real-time stats
- Less expensive than competition
- Difficult to attach sensor to racket
- Does not have internal memory
- Recognition algorithm could be improved
We ran a feature a few weeks ago on Qlipp. This is a new tennis sensor created by a team called 9 Degrees Freedom. The device was successfully crowdfunded on Indiegogo, raising nearly $100,000 (50% above target) up to August last year when the campaign closed. Qlipp is different from other sensors you can purchase today. It attaches to any racket to track your game, while at the same time providing a dampening effect.
The nice folks at Qlipp sent us a sample sensor to test out, so we decided to attach it to a Babolat Play Connected racket to see how it stacks up.
Ease of use
Use of information
Inside the box you will find the Qlipp sensor and a micro/mini USB cable. The device itself is very light. It is made of plastic and weighs only 8 grams, which means you will barely feel it on your racket.
Zepp and Sony place their sensors on the butt of the racquet. Babolat‘s sensor is built into the racket, Pop goes on your wrist. The Qlipp, on the other hand, sits on one side of the string bed, and on the other side you have the plastic clip.
The device is square in shape and has a length of 29.55mm, width 25.66mm and height 14.74mm, so its slightly chunkier than a traditional tennis racket dampener. Still it does not seem out of place and just comes across as a bigger than average vibration dampener. Having a sensor attached to your strings seems logical to us, as it is closest to where the racket head strikes the ball. Which means it has the potential to provide you with the most accurate statistics.
The Qlipp charges with a standard USB cable and has a battery life of over 4 hours. More than enough for any tennis match.
Ease of use
Before heading off to the tennis court, you need to download and install the smartphone app. Follow the steps to register your details by answering a few basic questions. Simple enough. The tennis sensor is currently the only one on the market which connects with the Apple Watch. A major selling point. So if you are lucky enough to have one, head off to the Apple Watch app on your smartphone and do an installation. Again, it was all a seamless process for us.
Next it was time to attach the sensor to our racket. This is where things started to get a bit more difficult. The device has something they call “twist and lock” technology. Make sure you watch the video on the Qlipp website before attempting to attach the sensor. We didn’t and almost ended up damaging the strings on the racket. Had we watched the video beforehand, it would have been an easier process.
When attaching the sensor, make sure the Qlipp logo is upright and the charging port is facing down. Place the sensor in-between the strings and twist it until one of the knobs hits the strings. Push the portion in-between the knobs while you continue to twist the sensor. That last bit is the tricky part – the stiffness of the string resists the user’s attempt to twist the last knob in place. Or perhaps the strings on our racket were simply very tight.
Once the sensor was attached to the racket, we would have preferred to keep it on at all times, but that is not possible because the rim of the racket is in the way so you can not charge the device while it is attached. Perhaps with a bit of practice the process of putting it on gets easier.
Nevertheless, once its on, the sensor feels very secure – a huge factor with a string mounted sensor. And this is probably the reason it needs to sit tightly against the strings. We didn’t feel it was in any danger of flying out during game play – something that we’ve all had happen with regular vibration dampeners.
To use Qlipp, simply switch it on by pressing on the middle part of the device. A blue light will start flashing. Launch the app and Qlipp will automatically connect via Bluetooth. The home screen of the app is divided into 3 sections: play, video and tutorial. Click play. Your session is now being recorded in real time.
If you are distracted by the blue flashing light – the app allows you to toggle the option to keep the light switched on or off during play. You can even switch audio on or off, depending on whether your opponent objects to your virtual coach shouting out your stats during gameplay. We could definitely see the use of leaving the audio on when, for example, practicing serves.
The log records what type of shots you hit and records the speed, spin, and how close to the sweet spot you hit the ball. It is worth noting that the unit does not have any internal memory, so you do need to bring both your Qlipp sensor and your smartphone onto the court in order for your measurements to be recorded and saved. However, your smartphone does not need to be near as the sensor has a detection range of 50 metres. A regulation tennis court is 23.77 metres long and 8.23 metres wide for singles matches and 10.97 metres wide for doubles matches.
In regular play, the Qlipp functioned and had the feel of a regular dampener. We did not notice any change in weight, and did not hear any pinging sound we’ve heard about in other reports. The connection did not drop even once. So the overall experience during play was seamless.
Its 2016 and thanks to Qlipp you can glance at your watch to see time elapsed since the start of the match, speed of last shot and a variety of other statistics. The device also pairs to your Apple Watch HR sensor and shows a heart rate reading in the left hand bottom corner of the screen. The tracker also pairs with Android Gear. We can only wonder what we will get in 2017, 2018 – perhaps your watch will keep score and make line calls…
It makes all the difference to be able to glance at your watch any time and see your latest statistics. Opening a smartphone app and analysing your session’s statistics after the game is all well and good, but to be able to do this in real time is nothing short of magical.
Here are a few more pictures of the Qlipp sensor.
Use of information
The device measures every part of your stroke (forehand, backhand, and serve), including ball speed (it uses the rackethead speed to derive the estimated ball speed), spin (top spin, slice, flat), and sweet spot accuracy of each shot. After the session, you can play back and review every stroke in slow motion (if you have switched on the video function), allowing you to gain more insight into your technique.
Everything is clearly laid out in the app, which is very intuitive and compares favourably with competing brands. The main screen consists of five sections:
- Progress: This is where you see your ‘score’ – an assessment of your overall playing ability. This is comparable to Babolat Play’s ‘Pulse’ score. An overall metric that assesses your current skill level. To calculate your score, Qlipp combines the average speed of your shots, spin depth and sweet-spot accuracy. You can also see ‘stats history’ – a chart which shows how your ‘overall score’ changed over time.
- Past sessions: a list of all your past sessions. Clicking on a particular session takes you into the ‘Overview’ screen which provides you with detailed statistics of your match or practice session.
- Play: the screen which allows you to start your hitting session in normal or video mode.
- Ranking: the social element of the app. The app allows you to see how your stats match up in the Qlipp community leaderboards, organize matches with other players or share your progress on social media.
- Settings: here you can choose whether you are rightie or leftie, toggle audio feedback and sensor lights and choose between metric and imperial units.
The stats are extremely detailed. For each game or practice match you will find an overall session ‘score’, duration of the match, number of rallies and number of strokes. The session log lists every single stroke broken down into various components – forehand, backhand, service and volley. Each stroke’s speed is displayed, along with stats showing sweetspot accuracy and spin. There is also a visual representation of all metrics via a chart.
You will find various other stats including your top and average session speeds for forehands, backhands and serves. Also, there is a spin breakdown and a sweetspot average for both your forehands and backhands. Finally, the skills screen shows a visual representation of your consistency and stroke heaviness.
All in all, the level of detail and granularity of the stats is extremely impressive and not something that we have seen with the Babolat Play or Sony Tennis apps. And, everything is laid out in a intuitive, clear and organised manner.
The Qlipp app also provides a video recording feature, which overlays your stats on top of the video. This is a great tool for finding out what you’re doing great and what you need to change. Qlipp uses the inbuilt camera on your smartphone to record a video session. Like the Sony sensor’s companion app, the Qlipp tags your recorded video so you can skip to specific shots during the footage. You can also filter strokes according to stroke types and, if you want to dissect your form, play back your video in slow-motion.
But, how does Qlipp fare against the competition in terms of accuracy?
As mentioned, we strapped it on to a Babolat Play Connected racket. This is a racket with a sensor built into the handle so in theory should represent the gold standard in accuracy. In the coming weeks, we will perform a similar test comparing Qlipp with the Sony Smart Tennis Sensor.
Babolat Play Connected
Time in play
1 hr 46 mins
1 hr 46 mins
Shot breakdown (forehand/backhand/volley)
63% / 25% / 12%
59% / 15% / 3%
Top service speed/average service speed
109 km/hr, 98 km/hr
83 km/hr, 63 km/h
Both apps produce a plethora of other statistics – however, they differ in the way they track them. For example the Qlipp app provides a km/hr reading for each shot, the Babolat Play app just provides a % of a ‘best’ value (apart from the serves). Which means, it is extremely difficult to do a direct comparison of other statistics.
Overall, the stats that are comparable are not too different. The one area where Babolat excels is the serve recognition algorithm. Out of 647 strokes, Qlipp only recorded 2 serves. Babolat recorded 129 serves. We suspect that Qlipp classified most of the serves as forehands – hence the difference in the forehand shot breakdown percentages between the two apps.
As for overall accuracy, we would place Babolat’s sensors ahead of the Qlipp at this point. But, does it really matter? The goal of these sensors is to improve your game over time. As long as you are consistently using the same device, you are comparing like with like. Which means your trends over time will show whether you are improving or not.
Our overall experience with Qlipp has been positive. The device will give you an indication on areas you need to improve on and will help motivate you to play more. The stats are laid out in a clear and intuitive manner, and are easy to understand.
The ability to see how your current session compares to your historical sessons gives you something to aim for. Whether you’re playing a match or just hitting around, practice should always be done with a plan and a purpose. Qlipp helps you to visualise your game, analyze your swing data, and compare and track your progress over time.
You may have noticed the increasing number of gadgets and tennis sensors related to this sport. If you are an aspiring tennis player or even just a hobbyist, this is excellent news. Qlipp is the newest entrant, and our impression is that it stands a decent chance of making a name for itself in this young, competitive market.
Essential reading: Tennis trackers and gadgets to track your game
The software offers a ton of information, much more than competing brands. So you will get very detailed breakdowns including easy-to-read graphs of different strokes used, speed of each stroke, amount and depth of different spins and your average sweetspot. Best of all if you hit 250 shots, you will have a detailed log of each shot you take. Oh, and don’t forget the ability to see real-time stats during game play on your Apple Watch and Android Gear. This definitely gives the competing brands something to aim for.
On the negative side, our major gripe is to do with attaching the sensor on/off the string bed. This is something Qlipp should improve on for the next version. Perhaps if it was made of softer material it would allow for easier securing? The sensor’s algorithm would also benefit from further improvements, particularly when it comes to identifying serves. Also, if you are super sensitive to the weight of your racket, 8 grams might make a difference. It didn’t make any difference to us.
Qlipp Tennis Sensor
At $99, the device is good bit cheaper than rival sensors from the more established brands. The company seems really committed to improving their product, they are super responsive and constantly churning out firmware updates. Apparently Qlipp is already working on a forthcoming firmware update that will allow you to tell the app you are about to only hit serves. The app will then record angle on incidence, pronation and tailor its serve recognition algorithm, which will ultimately improve its ability to recognise your serves in regular play.
So even with the difficulties involved in putting the sensor on, this seems like a solid product which will give the more established brands a run for their money. With some further improvements we see it going many places.
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6 thoughts on “Review: Qlipp tennis sensor”
Did you actually record whether the Qlipp was recording the right shot and the right spin? Or did you just assume it was correct? I would think the latter. The Qlipp doesn’t detect the correct shot more than about 80% of the time, which is nowhere near enough if you want good analysis.
Hi – we did. The table where we compare it to a Babolat Play Connected can be seen above. You can see the breakdown is fairly similar. Qlipp does struggle though to recognise serves.
Sorry but those comparison numbers look wildly different to me. The Qlipp registered 78 more shots than the Babolat Play is what that tells me?! Also, you’ve shown what shots were registered by the devices, but not whether that was in fact the shot played. Unless I’m misreading something.
For our test – the devices both tracked around 600 shots – we provided a % breakdown of shots played to give an indication of the metrics. I am guessing – during a match – there are lots of shots which are not really in-game shots – you may for example just lob the ball over the net to give your opponent a tennis ball to serve with. Babolat may be better at weeding these out. I think the reason Qlipp showed a higher % of forehands – its because it sometimes misinterprets a serve as a forehand. Also – this is why the Babolat % does not add up to 100% – we excluded the serves (the Qlipp didn’t recognise very many).
In my view – this is the first generation of these devices (apart from Babolat). Its far from being an exact science at this stage – and we have to be realistic in our expectations. Maybe in 2-3 years, when they start monitoring your movement in 3d you can compare shot by shot how good they are. For now, this is as good as it gets.
The Sony is as good as it gets, and without confirming what was “actual” (through video analysis for example), versus what each sensor said would be the only way to check accuracy. Otherwise you’re, as you said, “guessing”.
I have the Qlipp. I like it. My gripe is they need apps for major smart watches. For example, I have a Garmin Fenix 5x. I would love to see my shots on it. I sent Qlipp an email on this and they never responded.