Zepp – Review of the Sensor that Promises A Lot. But Does it Deliver?

The Zepp Tennis Sensor is a great example of the power of marketing. Criticized by its detractors (with good reason), the Zepp still has a lure even after the box arrives at the door and you download the app onto your smart phone or tablet. It looks good. Then comes court time.

Device Usability 2/10

We let out a few choice expletives when getting the Qlipp onto the string bed for the first time. That was nothing compared to getting the Zepp “flex-mount” over the butt of the racket. It never feels as though it’s quite resting on the cap. It’s a real fiddle.

Then comes trying to hit balls with the Flex-Mount. Here you have two choices: over-grip it or deal with it. The “deal with it” option is uncomfortable from the start and becomes more so as a hit session goes along. The rubber mount doesn’t absorb moisture the way an over-grip can. Once you’re in to a session, keeping the racket firmly in hand is a problem. Over-gripping makes it bearable but has the additional problem (and expense) of re-gripping every time you use it.

Enter the “Pro-Mount”. After much criticism of the Flex-mount the Zepp producers manufactured a small plastic mount in which the Zepp device sits during a session. Rather than removing the butt cap (a la Sony), the Pro-Mount is stuck to the cap with 3M adhesive tape. We’re guessing it’s called “Pro” because you would want to have a spare racket in your bag that permanently has the Pro-Mount affixed to it. Not ideal.

On the plus side, the Zepp does have internal memory so that play data can be downloaded rather than captured live. We found the calibration process a bit painful at first but no problem after a few hit sessions.

Zepp Scorecard

Zepp Tennis Sensor. Uncomfortable to use with inaccurate data


  • On-Court: Attachment is a pain. Pro-Mount is no solution - Score: 2/10
  • Data Accuracy: No shot by shot analysis. Heat Map is inaccurate - Score: 3/10
  • App: Great marketing. Video coaching sessions. Easy to navigate - Score: 7/10
  • Video: Nada, Niente, Bupkis, Nothing……although there is 3D Dude! - Score: N/A
  • Overall: Doesn’t pretend to have analytics of Sony SS and nor should it. The Zepp is no game improver - Score: 3/10

Data 3/10

Zepp Tennis Sensor. The Session in Progress page doesn't provide shot by shot analysis, just a percentage for each shotData? What data? Did someone say something about data?

The Zepp doesn’t seem to pretend to be as analytical as the Sony SS, but the modicum of data that the Zepp produces doesn’t tell us much about what a player is doing on the court. In our play testing, we found the sensor picked up our groundstrokes well. It read whether the shot played was a forehand or backhand to 98%, but the live data output is only a percentage of shots played – no spin, power, swing speed or any other measurement.

The “after-the-fact” data is, again, picking up the flat shot. That seems to be the default shot registered when the actual spin is indiscernible. For details of our opinion of the “flat” sensor measurements, click here.

Further, no matter how many rackets we tried and registered through the App, the heat map always registered forehands hitting the lower part of the string bed (towards the throat). Now, we’re not Fed, but we know from hours, days, months and years of video analysis that the vast majority of shots played by good players make contact with the strings slightly higher on the frame than the middle. Using the Pro-Mount didn’t seem to make a difference and nor did changing the player.

Lastly, Zepp only picks up forehands and backhands. Don’t expect to improve your volleys using Zepp as it doesn’t differentiate between groundstrokes and volleys at all.

App 7/10

Zepp Tennis Sensor. App front page featuring Milos RaonicAn App is only as good as the data that’s supplying it and on this count, the Zepp fails quite miserably. Where it wins out is on look, feel and general usability.

It’s pretty easy to navigate through your past sessions. Each session has its own Intensity Score, which is based on the amount of time spent on court, total active minutes and the number of shots/rallies played.

It then provides a consistency score which is based solely on where the ball met the racket on the string bed. It’s a good idea completely let down by the inaccuracy of the data provided by the sensor. We’ve found in testing that the Sony Smart Tennis Sensor is a fair way shy of 100% when it comes to heat mapping the string bed. It seems to be one of the most difficult aspects of “sensor-ing”. The bottom line is that we like the idea of the Consistency Score using Heat Map data, but the score’s irrelevant if the heat map data is wildly inaccurate.

The final metric shown by the Zepp app is racket speed, or at least racket butt speed as, like the Sony SS, that’s where the sensor is placed. The accuracy is questionable and the value to the player isn’t much better without further information such as a spin measurement or ball speed extrapolation, neither of which are provided.

The version of the app that we used was 2.0. Full screen layouts and heat maps seem to have been discarded in this version, while older versions appear to have more detail.

Video N/A

Zepp Tennis Sensor. 3D view in serve practice mode. Useful in some respects but would be better if it could be used for all shotsOK, so why are we bothering to do a video write-up when the Zepp doesn’t have a function to link to your phone or tablet camera and film while recording play and practice data?

What about 3D dude! Inside the App you have the option to either “Start Play Tracking” or “Practice Your Serve”. The device will record  your serve data as part of the play tracker, but there’s a serving specific function that you can use to practice your serve. It’s 3D Dude! Note that data recorded by the 3D dude side of the app doesn’t seem to be transferrable to the Play Tracking side.

3D dude will illustrate and record any service swing and play it back. The idea being you get to see your serve from a variety of angles (front, back, sides and even on top). While somewhat useful to see where a player is decelerating through their swing, it holds little value otherwise.

An on-screen tap then provides the detail of the serve just hit (or a previously recorded serve) with measurements for racket speed, spin and what Zepp calls ball speed potential (use of the word “potential” probably negates the need for a disclaimer regarding the accuracy of that number). A time measurement is also given for backswing and impact. Why, we’re not sure.

The whole thing looks interesting but we’re puzzled as to why 3D dude isn’t offered as a tool for all shots. Why just the serve? Before you ask, yes we tried using it for other shots without success. We’d also suggest 3D dude work harder for an apparel contract or at least purchase some tennis gear from his local pro!

Zepp has also managed to rope in Milos Raonic and some other lesser known tennis professionals to produce coaching videos that can be viewed inside the app. If interested, look them up on Youtube where you can view them for free.

Overall 3/10


The App is really user friendly and easy to navigate. The fact that the Zepp has its own storage means you won’t necessarily need other devices on court with you. 3D dude provides light entertainment and some of the in-app coaching videos are worth a look.


The two ways in which the Zepp can be mounted are equally poor. One requires an uncomfortable grip while the other sacrifices a racquet to a stick-on holder. The Zepp doesn’t pretend to produce in-depth, shot by shot data. What it does produce, however, is questionable in its accuracy and not high on a value matrix either.

Final Word on Zepp

If you’re wanting to save yourself time adding coaching videos to your Youtube favorites, grab the Zepp. Any half decent player in the market for something that will seriously help improve their tennis should look elsewhere. Any coach looking for an analytics tool should do the same.


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