Tennis Warehouse: Zepp Tennis Sensor Playtest

Discussion in 'Racquets' started by TW Staff, Feb 3, 2014.

  1. mad dog1

    mad dog1 Hall of Fame

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    i installed the pro mount on the trap door of my pure storm gt thinking i could use it with a few of my other babolat sticks. well, after about 5 mins of spirited rallying, the sensor flew off with the trap door! :shock: i tried again and within mins, it flew off again so i had to add some athletic tape to hold the sensor + trapdoor to the butt cap.

    the pro mount works much better for me than the Flex mount but if your hand hangs off the end of the handle, it's still going to be an issue for you.
     
  2. mad dog1

    mad dog1 Hall of Fame

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    Zepp sensor + Pro mount

    i think the pro mount is definitely the preferred mount. it feels and works better than the flex mount. no more twisting causing the misalignment of the sensor.

    so i focused on testing the accuracy of the measurements this time out. with the flex mount, i was getting some really strange readings so i spent 2 mins rallying specifically hitting only forehands. good news! this time the app reported that all the strokes were forehands. i next spent 2 mins rallying specifically hitting only backhands. the app reported the majority of my strokes were backhands, however there were 3 forehands that were recorded. i was a bit puzzled initially until my hitting partner reminded me that I started a few rallies by feeding the ball on my forehand side. the other thing that causes the sensor to record a forehand is when you lean forward and pick up tennis balls on the ground by leaning over and bouncing the ball off the pavement with the top of the racquet. mysterious forehand data explained!

    did some more 3D serve practice...

    1 pattycake serve. 6/10 spin. 1 serve 8/10 and another 9/10 while the rest were all 10/10 again. i do think the spin measurement isn't entirely accurate
     
  3. julian

    julian Hall of Fame

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    Changing rackets

    If you do switch rackets do you see a change of power numbers for serve?
     
  4. julian

    julian Hall of Fame

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    Please see post number 203

    Please see post number 203
     
  5. julian

    julian Hall of Fame

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    6 grams

    There was a rumor that the newest version is 6 grams
     
  6. WhiteStripes

    WhiteStripes Rookie

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    I and a few of my friends have spent a bit of time with the sensor over the past few days. The pro mount feels definitely better for me. I don't think it affects my swings, but I do still notice/feel it. The lighter weight of the sensor/pro mount is also much better, and while it did make my racquet feel a little more whippy, it was not close to as dramatic as the flex mount.

    Also, no issues with the sensor/mount flying off and taking off the trapdoor. Closest it got to that was on a mishit on a return off a big serve from my friend, and the sensor nearly fell out of the mount, but still hung on... barely. The mount, though, still remained firmly attached.

    One thing that seems to have change using the pro mount v. the flex mount is the reading of the impact location. Before, using the flex mount, the highest percentage of my shots registered in the upper portion of the stringbed. This was consistent over a number of hitting sessions. This is fully what I expected and (at least from my perspective) accurate. Over several hitting sessions totaling about 4 hours with the pro mount, the impact location readings are consistently showing the highest percentage in the middle of the stringbed (both close to 80% for both my forehand and backhand, which is in stark contrast to prior readings I got like the example I noted in one of my prior posts). My strokes/hitting did not change one bit switching from the flex mount to the pro mount, so it was a little weird to see the impact location readings change that much.

    None of the other readings seems to have changed though from switching from the flex mount to the pro mount, including the screwy 3D serve readings... which was interesting since my friend brought his old Speedtrac radar gun (the device you set up at the net) to do a ball speed comparison.

    The flat patty-cake dink serves are still registering 7 or 8/10 spin readings, and the racquet head speed and potential ball speeds are a bit strange. For example, on very slow warm up serves with my hitting arm starting already in the trophy position and swinging very slow, I was registering a racquet head speed in the upper 30 mph range (and also registering 10/10 spin). When I started hitting my usual paced serves, the readings were all over the board, with racquet head speeds ranging from as low as 34 up to 58, which is a massive variance for serves that (in terms of swing speed) were all similar across the board from my perspective.

    To further illustrate how unusual the readings are, my fastest serve registered on the Speedtrac was 104 mph using a modified Pure Strike. That serve (which was obviously a flat serve that, at least in my eyes, was struck cleanly with very little spin) registered a 49 mph racquet head speed and 69 mph potential ball speed, with 10/10 spin. In contrast, the fastest potential ball speed for a serve that I got on the Zepp app was 84 mph with 58 mph racquet head speed and 10/10 spin readings, and that was a second serve/kick serve that registered 67 mph on the Speedtrac using a Pro Staff 95S with the sensor in the flex mount.

    The Speedtrac has its shortcomings, but using it side by side with the Zepp indicates some issues with the Zepp's calculations.
     
    Last edited: Jun 6, 2014
  7. WhiteStripes

    WhiteStripes Rookie

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    Not too much of a difference, although there are instances where I've gotten a little higher power readings off my Wilson Pro Staff 95S (which is right now in stock form strung with poly) even though it's much more lower-powered compared to my Pure Strikes that are strung with a gut hybrid. I assume that's due to the fact that the PS95S is swings very, very fast due to an extremely low swingweight and thin beam, allowing me to generate a lot of racquet head speed.

    It appears to me that Zepp's power calculations are heavily dependent on just racquet head speed, as I don't think it's possible for the sensor to account for other factors like the racquet/strings you're using. At the end of the day, I think the supposed main benefit of the power readings is to track performance over time (or at least that's how I see it), like over the course of a match (e.g., you're losing racquet head speed over the course of a match, and you can try to pinpoint when that drop off occurs) or even over weeks or months to track any improvement in racquet head speed/pace (although this would be more helpful assuming you're using the same equipment throughout to take out any variables).
     
  8. julian

    julian Hall of Fame

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    Power numbers from TW

    Just to compare with power numbers from reviews of TW
    Wilson Pro Staff 95 S Power 74
    Pure Strike 100 Power 83
    I have zero knowledge how power numbers were obtained by TW
     
    Last edited: Jun 6, 2014
  9. WhiteStripes

    WhiteStripes Rookie

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    My main racquet is a Pure Strike 18x20 at 12 oz, and a little under 8 pts HL strung with natural gut mains / poly crosses, w/ a Babolat RDC measured SW of 329. It is substantially more powerful than my Pro Staff 95S sticks, which I like to hit every now and then just for kicks because it's a fun racquet. In stock form, it's extremely low powered. Like I said, the power readings are fairly consistent across the board, and sometimes I get a higher power reading from the Zepp, presumably due to higher racquet head speed.
     
  10. julian

    julian Hall of Fame

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    Potential ball speeds

    Potential ball speeds for serve should be higher for Pure Strike comparing to Wilson Pro Staff 95
    I cannot argue with your numbers but I am surprised.
     
    Last edited: Jun 6, 2014
  11. WhiteStripes

    WhiteStripes Rookie

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    I agree, but I'm not sure that Zepp's sensor can really take into account the equipment (racquet, strings/tension) that the player is using. So I assume the power readings are relying a lot on racquet head speed as the main variable.
     
  12. julian

    julian Hall of Fame

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    I corrected 71 to 74

    I corrected 71 to 74
     
  13. jonestim

    jonestim Professional

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    I would agree with that. It also most likely assumes a 27" racquet so if I were to put it on my Graphite 100 Longbody it would not adjust the speed potential even though I would have more leverage. It seems like the readings are most likely good to compare your strokes today vs previous days, not vs different racquets.
     
  14. jayserinos99

    jayserinos99 Hall of Fame

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    Tennis experience/background:
    4.0C, been playing for the past 20 years, starting as a junior.

    Describe your playing style (i.e. serve & volley):
    Primarily doubles specialist but all-court singles player typically using a lot of spin and touch, tend to hit big kick and slice serves, topspin semi-western forehand, flat 2-hand and 1-hand slice backhand. Will come into the net when there is an opportunity.

    Current racquet/string: modified Babolat AeroPro Drive 2013 strung with Solinco Tour Bite 16L at 53 lb. Also using a 2nd generation Babolat Pure Drive (swirly) strung with Solinco Tour Bite Soft 17 at 53 lb.

    How many hours did you play with Zepp?
    6 hours with my modded AeroPro Drive. 4 hours with my modded Pure Drive.

    Was the device easy to attach to the racquet?
    It was easy to attach, but hard to keep in place. I used the flex mount because I wanted to be able to switch it from frame to frame. At first I just attached the device on top of my overgrip; what I noticed was that during much more intense hitting, the mount would move and I would have to adjust it after each point. I don’t think it drastically affected results, but it was definitely a product flaw. What I ended up doing was taking off my overgrip and mounting the flex mount onto the bare leather grip, then wrapping the overgrip on top of of the mount. It gave the buttcap a slightly more pronounced ridge, much like the Kafelnikov buttcap, but I tend to hold my grip there anyway and not over the buttcap so it actually helped secure my grip. I also noticed slightly more vibration in the feel of the frame as the flex mount moved during hitting.

    Given its weight along w/location on the racquet, was it a hindrance?
    Yes unfortunately. I’m really sensitive to how my frames play and the Zepp made it too headlight and too fast through the hitting zone. My Aeropro Drive target spec is 335g, ¾” HL, 320sw. After installing it on my AeroPro Drive, it came out to 356g, 1 ¼” HL, ~320sw (rough estimate as I only have access to a scale and balance board). Given that I use a leather grip, I would have to actually switch back to a synthetic grip to try and get the weight back down so that it doesn’t ruin my strokes as well as the playtest (to try and keep the variables within reason).

    How easy was it to upload and view the data on the app?
    Using an iPhone 5S, it was really straightforward and I didn’t have any issues with uploading the data. I liked how you can switch from percentage to the exact number by clicking on the button. Navigation within the app was easy as well.
    What did you like about the app?

    Pretty easy and intuitive to use and it didn’t crash on me. Setup was a breeze. I got to play around with the 3D Serve Mode and I after viewing the swing path on my serve, I tend to have quite a bit of backswing according to the app, that was very useful to know.

    What did you dislike about the app?
    There was no way to do a data dump (e.g. CSV file) with corresponding times of when the swing took place. Also the power level data points are only just numbers and don’t have any units of measurement. (Are we to assume it’s miles per hour?)

    Was there anything you thought was missing?
    I’d like to see a correlation between different points and what transpired in each point either in another mode or a continuation of the play-tracking mode with an updated algorithm for points played. Also I’d like a distinction between groundstrokes and volleys as well as a better distinction between serves and smashes. Actually I wouldn’t mind a Zepp representative contacting us on the boards on how this gets calculated.
    I tend to wonder if string type, tension, frame type, etc. makes a big difference in the results as well.

    How did you use the data you received from the app?
    I kept notes after each hitting session and tried to correlate what I did in the session from what the data showed. I paid attention to power levels because it showed when I actually went for my shots versus taking it easy (a big problem of mine). I also paid attention to where I was hitting the ball and it showed I hit my forehands more toward the bottom of the frame, which is consistent of my semi-western forehand. On my backhand, I hit more center/upper-center than bottom of the frame.

    Final Thoughts
    My overall review of this product is that I feel it is incomplete but that it is a great first step in truly understanding your game. The Zepp sensor is only one part of the overall equation to figuring out what is your game. A friend of mine put it bluntly: “A sensor that doesn’t tell me the depth, direction, and spin of each shot that I hit is worthless.” I’m not as unforgiving as my friend, but I believe that there has to be another way to calculate the effect of each shot you hit. I don’t know the exact technical specs of the Zepp, but I would have to imagine that the next version will be a lot more streamlined and have the ability to detect racquet face angle in respect to x, y, and z plane. Then there can be an algorithm calculated for the effect of each shot based on racquet face angle, type of shot, power level, and where the ball was struck on the stringbed.

    Lastly I’d like to thank Tennis Warehouse and Zepp for letting me playtest this interesting product!
     
  15. WhiteStripes

    WhiteStripes Rookie

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    (Part 1 of 3)

    I think I’ve spent enough time with the Zepp sensor to do my full write-up review, which is in large part a summary of my comments from prior posts.

    I’d like to first thank Zepp and TW for the opportunity to do the playtest. I think it’s darn neat and admirable what Zepp, ShotStats, Babolat, and Sony are trying to do. I know it’s very early in the ballgame in terms of this technology, so I’ve gone in with pretty tempered expectations and not expecting much in the way of the sensor divulging much I didn’t already know about my game or providing some catalyst/spark to improve my hitting.

    Tennis experience/background:

    25+ years of playing tennis. Highly competitive as a junior. Trained some at Bollettieri’s. Ex-USPTA. Wish I could spend all day on the tennis courts like when I was a kid with no responsibilities, but my playing time has been drastically scaled back over the past several years. Played USTA leagues at 4.5.

    I should also mention that, in part due to the fact that I’m still in recovery mode from a recent injury, I’ve had a number of friends of varying abilities (some of whom are Talk Tennis lurkers) try out the Zepp sensor. They range from a 4.5B rated male not too far removed from college with big strokes who fits the profile of a baseline basher to a 3.5C rated female who plays exclusively doubles in USTA/WTT.

    Describe your playing style (e.g., baseliner w/heavy spin, serve & volley, etc.,):

    Grinder/counterpuncher.

    Current racquet/string:

    Babolat Pure Strike 305 18x20, modified to 12 oz., a little under 8 pts HL, with a Babolat RDC measured 329 SW.

    Other racquets that were used during this playtest (a mixture from my friends and me) included a Babolat Pure Strike 305 16x19; Babolat Pure Strike Tour; Babolat Pure Control 95+; Wilson Pro Staff 95S; Head IG Radical Pro; Volkl PB 10 Mid; Prince O3 White; and Prince TT Graphite 95

    Which mount did you use? Was the device easy to attach to the racquet?

    Both were used, with more time put on the flex mount due to multiple users/multiple racquets. As mentioned previously, the pro mount when affixed to a Babolat buttcap fits nicely on the trapdoor, which then can be popped off and transferred over to another Babolat racquet. Otherwise, the adhesive on the pro mount appears to be very strong, and once the mount is on there, it’s not going to be easily removed and transferred to another racquet.

    Given its weight along w/location on the racquet, was it a hindrance?

    I understand why Zepp would want to place the sensor at the buttcap to try to minimize the effect of added weight to a racquet. Unfortunately, as I expected going in, the answer to both (weight and location) is yes. On my forehand and serve, I choke way down on the grip (for example, on my forehand, the bottom of the buttcap typically sits in the palm of my hand right around the top of the fleshy base of my thumb). With the flex mount, the silicone part that slides over the buttcap was a bit of a distraction, although I can’t say that in actuality it affected my shots. Still, it was extremely noticeable though, and when changing grips on my strokes, I can feel my hand tugging away/catching the silicone handles that slide over the grip. In addition, over the course of about 4 or 5 hitting sessions, I developed a pretty tender callus right in that fleshy part of the thumb in the palm of my hand where the buttcap normally sits.

    A number of my friends also commented about the flex mount being a distraction in terms of altering the feel/shape of the handle, although I don’t think any of them hold their racquets as low as I do on the grip.

    I’m the only who has tried the pro mount (since it’s on my stick). Unquestionably, it’s the better mount for me. Although I still feel the mount/sensor in my hand, it’s not as distracting as the flex mount. More importantly, the pro mount weighs substantially less than the flex mount, which was extremely noticeable between the two. Both made the racquet much more headlight and whippy, but I felt with the flex mount, it altered the balance and playing characteristic of my racquet way too much for my liking. I felt the pro mount didn’t materially affect my strokes like the flex mount did.

    With both mounts, I did not have any issues with slippage or the mounts rotating during play as others have reported. I also have not had any issue with the pro mount pulling off the trapdoor or any part of the buttcap as others have reported.
     
    Last edited: Jun 7, 2014
  16. WhiteStripes

    WhiteStripes Rookie

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    (Part 2 of 3)

    How easy was it to upload, view and understand the data on the app?

    Very easy to sync, although the first time I tried to update the firmware, it would not connect to the sensor via Bluetooth despite multiple attempts. I gave up that night, tried the next day, and it worked. Since then, no issues with connectivity between the sensor and the app/my phone.

    I like to sync the data during breaks, and I can take a quick peek and see what was recorded. The information (e.g., how many forehands, backhands, etc. hit; % of shots hit on stringbed; the swingpath in the 3d serve mode; and so on) is generally straightforward and self-explanatory, and should be understandable to any tennis player. The only issue is what unit the power reading is based upon, since it’s not clarified anywhere in the app or manual. It’s definitely not racquet head speed and presumably not mph since the power readings for my serve are substantially different than the racquet head speed ratings and potential ball speed in the 3D Serve mode. I’m working on the assumption right now that it’s similar to Babolat’s Play – i.e., it’s the percentage compared to a pro player – but I could be completely wrong. It would be nice if Zepp would clarify this.

    No issue with viewing the data on the app. I do think it could be a bit more efficient if options to view certain data (e.g., location impact) could be accessed quickly in less clicks/screens rather than having to navigate through several menus/sub-menus first. Same with perhaps some shortcut to go back to certain main menu lists rather than backtracking screen by screen. But it’s a relatively minor complaint, and it doesn’t really bother me at the end of the day. Although I have not used the Babolat Pure Drive Play, it looks like the menus are a bit more elaborate/flashy compared to Zepp's (3D Serve practice notwithstanding), but that’s really a non-factor for me. Simplicity and ease of use are of more importance, and Zepp’s app works fine to me without any issues.

    I should also mention that a number of users set up accounts for the sensor, and there was no issue switching from user to user.

    What did you like about the app?

    In terms of the app itself, see above.

    What did you dislike about the app?

    In terms of the app itself, see above.

    Did you find the data you received from the app useful? Please explain your answer.

    I was skeptical going in whether devices like this, Babolat Play, etc. would be helpful to me. I’m well familiar with my game and my strokes are grooved to a point that, frankly, the data these devices provide won’t really affect my game going forward.

    That said, while it’s not for everybody, I can certainly understand how some of the data can be used for players looking to improve and track their game – i.e., how consistently are they hitting on the sweetspot, how are they maintaining their power/racquet head speed over the course of a hitting session or a match (or over a longer term to track improvement if there has been technique changes to the player’s strokes), etc.

    One of my friends – the 3.5 female – in particular was SHOCKED to see that she was striking the ball all over the stringbed. Immediately after the break, she was intent on focusing in on hitting the ball clean, and upon on the next break was giddy to see a substantially higher percentage in the sweetspot. Out of all of the folks who tried the device, she seemed the most positive overall, and after I’m done toying around with the device, I may be in the generous mood and pass it along to her.

    As for me, the data is remarkably consistent in terms of the data in the Tracking mode. The only exception being the impact of location when I switched from the flex mount to the pro mount as I explained in a prior post. Some of the data is fairly rudimentary, like topspin, slice, etc. It would be nice if there could be some indication of the amount of spin on groundstrokes (right now it’s limited to the 3D serve mode, which is a bit inaccurate), although I understand it may be tough to decipher that information (especially if trying to quantify RPMs).
     
    Last edited: Jun 7, 2014
  17. WhiteStripes

    WhiteStripes Rookie

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    (Part 3 of 3)

    Did you find the data you received from the app useful? Please explain your answer. (con't)

    Also, it appears that the reading of flat, slice, topspin is largely dependent on swing path. My swing path is actually not too steep, and my topspin shots are often topspin drives rather than loopers. The sensor is reading some of these topspin drives as flat shots rather than topspin. I actually tested this on drop feeds and hitting hard topspin drives with a lower trajectory over the net, but with a substantial biting topspin with noticeable jump after the bounce on the opposite side of the net. Quite a number of these shots were registered as flat. In the same vein, I’ve had slices on both forehands and backhands that registered as flat due to a swing path that isn’t as extreme. Also, the sensor does have a tendency to pick up high forehands at times as a serve rather than a forehand. No volleys are recorded at this point, which apparently is difficult for these types of sensors to pick up/discern from a groundstroke.

    To me, the 3D Serve practice has great potential to be useful as a tool for those looking to improve. While it would be ideal to see both video and have a pro personally examine the serve for flaws, I think the user being able to see his or her swing path on the serve can be very useful. The other data right now in the 3D Serve mode, as has been discussed at length by a number of posters in this thread so I won’t rehash it again, appears to need some work (e.g., the spin readings) at the moment. I believe Zepp just introduced the 3D Serve practice mode for the sensor/app, so it’s understandable that it may not be completely refined at the moment. Again, I do think the potential is there though, and as far as I know, no other sensor has the 3D stroke tracking right now which is a plus for Zepp. I wonder if it’s possible to introduce this 3D tracking to groundstrokes, although I have feeling a player’s movement might present some issues on that front.

    Any additional comments/suggestions?

    Right now, I think increased accuracy and refinement (e.g., the 3D Serve issues I mentioned above) in the data retrieved would be the main priority I’d like to see improved upon. That said, much of the data looks to be pretty accurate and the sensor/app works pretty well. The technology is still in its infancy, and I would guess there’s more down the pipeline that can be potentially useful/interesting to all levels of players, especially when used in conjunction with good coaching to track the player’s progress.

    Otherwise, the only other issue would be physical aspect of the sensor/mount, and if Zepp can reduce the size and weight of them, that would obviously be ideal. Of course, that’s probably not an easy task to do given the technology that needs to be packed into the device + the battery as well. In all honestly, while I felt a bit distracted by the location/weight of the mount and sensor, I would guess that many rec players (especially those starting off in the game/still learning the game and not as obsessive compulsive as many gearheads on these boards are about every minutia of the specs in their equipment) wouldn’t be able to tell any meaningful difference. Lastly, on a superficial note, it’d be nice if the device were a nondescript black color to blend in with the racquet, but I understand that’s not going to happen as I assume the bright green color was intended to purposely stand out to make the Zepp device visible to everyone within watching distance.

    Again, many thanks to TW and Zepp. Definitely a neat experience to try out this new technology. I’ll still be using the Zepp and posting further comments in this thread.
     
    Last edited: Jun 6, 2014
  18. julian

    julian Hall of Fame

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    Location impact

    Please see
    http://tt.tennis-warehouse.com/showthread.php?t=502149
    http://tt.tennis-warehouse.com/showthread.php?t=502149
    A video of Babolat Play Pure drive has a comment by Chris Edwards that his location is more towards the top of the racket.
     
    Last edited: Jun 7, 2014
  19. WhiteStripes

    WhiteStripes Rookie

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    Not everyone has the same preferred spot on the stringbed where they like to hit. While I hit in the upper portion of the stringbed, as many others do, other players instead may prefer to hit in the middle of the sweetspot. I don't think one is necessarily more "right" than the other. Just like preferred strike zones/contact points between different players may also differ (e.g., my hitting partners know that I like, and actually prefer, chest and shoulder high balls, whereas others may hate that).

    As I mentioned previously in this thread, I think the goal of the impact location on the Zepp, Babolat Play, etc. isn't necessarily to try to aim to hit the middle of the stringbed all the time. Rather, it's to find a player's preferred contact point on the stringbed, whether it be right in the middle of the sweetspot or higher, and track his or her strokes over time to ensure that he or she is consistently striking that area. There is a potential issue, like the case with my female friend, when the data indicates that she's not hitting one particular spot consistently, but rather the impact location percentages are spread out almost evenly all over the stringbed, even the side edges and bottom of the stringbed. In that instance, devices like the Zepp can be useful in identifying/showing the problem to the player, and then tracking the player while he or she tries to improve his or her swings to hit cleaner.
     
  20. julian

    julian Hall of Fame

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    An impact location different for serve

    I was trying to bring up couple of points very loosely related to a review of Zepp:

    1.An impact location for an "efficient" serve is different than for forehand and backhand
    2.A Zepp sensor could benefit from some built-in knowledge.
    3.Some types of rackets promote serve hit at the top part of a string bed (for example Yonex)
    4.A sample of impact locations from a match does NOT have to be "consistent" (especially in the case of a return of serve).
     
    Last edited: Jun 7, 2014
  21. kimguroo

    kimguroo Hall of Fame

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    Tennis experience/background:
    Describe your playing style (e.g., baseliner w/heavy spin, serve & volley, etc.,):
    I am 40 yrs old and I started playing tennis about 6 years ago. I've been trying to play tennis as much as I can since I started. (I used to play almost every day and currently I play at least 10 hrs per week). My level is 4.0. My hope is to reach 5.0 but Realistically I would be able to reach at least 4.5. I am a baseliner and am used to hit mostly flat shots, but I try to hit more topspin shots nowadays. I am 5'5 and do not have strong serves. I'm trying to locate my serves. I have decent slice serves, and I need to work on kick serves more.
    Valleys are my weakest skills but I often go to the net. Whenever I have short balls, I hit approach shots then go to net even if I miss valleys.

    Current racquet/string:
    Aeropro GT and Warrior DB team
    Strung with MSV focus hex 1.10mm @ 58 lbs.
    Both rackets are modified to 12.4oz.

    Which mount did you use?
    Used both Flex mount and pro mount.

    Was the device easy to attach to the racquet?
    When I tried flex mount for the first time, I struggled a little to put the flex mount but later I realized that the silicon was much durable than I thought so I try to stretched more for the second time. After that it was easy to put the flex mount.

    Since Pro mount is easy to apply, I did not have any problem with it.

    Given its weight along w/location on the racquet, was it a hindrance?
    Yes it bothers me.
    I weighted my racket with flex mount and very surprised to see that total weight was 13.4oz. Since My rackets are already heavy, Weight of zepp system made it tough to adjust my strokes.

    Pro mount was much better than flex mount.

    I intentionally spent more time with flex mount because it seems like the flex mount is original idea of mounting system.
    I was worried about flex mounting because I grip the end of butt cap. (Usually my pinky is off the butt cap). After I put flex mount, I was very surprised about grip enlargement. My grip size is 4 1/4 (L2), but with flex mount the grip size went up 4 3/4 (L4). It was too big for me. Probably people do not grip the end of butt cap and it might be okay.

    I thought flex mounting system might give me blisters but Flex mount didn't give me bad feeling. Probably soft silicone material did not affect any. Also I did not have flex mount moving issue during the first session, but it moved a little when I tested more. It was not a big deal for me since I tried to adjust it very often to position the device on the right place.

    How easy was it to upload, view and understand the data on the app?
    I used both iphone 5S and android phone.
    I think it's the best part of zepp ^_^.
    Both were easy to connect and sync the device.
    I have the first version of Adidas micoach device. I thought it's very unique device but unfortunately, it was very hard to connect and sync device. Zepp did great job.
    Honestly, at first, I was a little doubtful about zepp system but it worked (upload/sync) very smoothly.

    What did you like about the app?
    Easy to read data.
    With 3D serve practice mode I was able to see swing path of serving motions.
    App does not cause any crash problem so far.
    Especially I like multiple player option which enables me to share zepp with other people.

    What did you dislike about the app?
    I don't see major problems.

    Background color of the backhand screen is blue and it made me difficult to read the black letters ("slice") on it.

    Did you find the data you received from the app useful?
    Please explain your answer.
    I've been always wondering how I hit balls. With zepp data, I was able to see wether I was hitting the right spots or not. It was very helpful. I was a flat hitter and now I'm trying to hit more topspin shots so these data helps me to see a number of flat strokes and topspin strokes. I had very interesting results. With my coach, I focused on hitting topspin shots and it turns out that my flat and topspin ratio was flat 55% and topspin 43% plus other. However, when I played with my friend, the ration changed to flat 81% and topspin 17% plus other.

    One of my friends always hit the strange places of racket and zepp data reveals that he hits off center for 92%. 80% was top of his racket area instead of sweet spots.

    Also 3D serve practice mode is very unique feature for zepp but it needs to be improved.
    My friends and I felt that data is inaccurate from time to time specially with spins. Most of time spin was 10/10 regardless of flat, slice or kick serve. Zepp needs to clarify the meaning of this data.

    Also I assume that serving ball impact point indicates with red color and I am doubtful with its accuracy. My friend had miss-hitting serve and the ball was flying to a fence but the hitting impact point indicated that he hit the ball toward to bottom. If he did that the ball should go to net instead of directly flying to the fence.

    Any comments/suggestions.
    As soon as I opened the box, I was looking for a manual. Surprisingly, there was no paper manual. I understand that paper manual could be wasted but I prefer to read paper manual for this kind of high-tec gadget before I use it. I also want power cord instead of USB only charger.
    I tested zepp with other people and some people want to put their results directly to Facebook so Facebook integration might be good idea.

    Most importantly Zepp needs to have better mounting system. Pro mount is better system but need to be improved more. There are several ways to improve. Use trap door mount system or make special butt caps. Nowadays, it will be easy to make testing mount system using 3d printer so zepp needs to make something better than current mount system (I think flex mounting system should be discontinued. No one likes it).

    I want to see each stroke data with more detailed information. Also it needs to add valley. Distinguish between valley and ground stroke. Overhead and serve (sometimes, High forehands calculated as serves).


    Overall, my first impression was that Zepp's built quality is solid. Many of high tec gadget often does not work well but generally Zepp system works smoothly.

    Zepp will have very tough challenge with babolat play, sony smart sensor and one more device (forgot the name).
    Babolat play system can't be transfer to other racket and expensive but Zepp should pay attention with sony smart tennis sensor system. Sony system might be the best system and it really helps to develop tennis skills in my opinion. It has so much useful features such as recording video mode which provide so much data on each shots with video but it is only available for Yonex rackets and Japan for now. I believe they just released the system this week. Zepp needs to improve several issues (especially mounting system) before Sony starts to sell their sensors outside of Japan.

    I do appreciate to TW and Zepp for this playtest. I had several bad experiences with high tec tennis gadget but this opportunity definitely changed my mind. Hopefully Zepp continues to improve their system and to be successful in their business.
     
  22. McLovin

    McLovin Hall of Fame

    Joined:
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    Messages:
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    Tennis experience/background:
    I've been playing for approx 36 years (turn 46 this year). I played D3 college, and and currently a 4.5 rated player. I also coach a girls high school team.​
    Describe your playing style:
    Predominately baseline, moderate spin, two-handed backhand. Will serve & volley in doubles and on grass.​
    Current racquet/string:
    Pacific X Feel Pro 95, Pacific Tough Gut 17 mains, 1.23mm MSV Co. Focus crosses.​
    Which mount did you use?
    Initially I tried the Pro mount. It was less intrusive when holding the racquet, but fell off (actually, 'flew' would be a better description) after 5 min of hitting. It is quite humid here in VA, so I assume that was why. I couldn't get it to stick again, so I changed to the Flex mount.​
    Was the device easy to attach to the racquet?
    The Pro mount was obviously easier to attach as it was simply sticking it on the end of the frame. The Flex took a little longer, but once you take it off & put it back on a few times, it becomes simple. 30 seconds tops.​
    Given its weight along w/location on the racquet, was it a hindrance?
    Since I hold the racquet low, it was a hinderance with either mount. But it wasn't anything I couldn't get past. I wouldn't play a 'live' match with it, but maybe a few games to test my strokes. I used the ball machine for most of my testing.​
    How easy was it to upload, view and understand the data on the app?
    At first I had some problems navigating the library, understanding where things were. However, I believe most, if not all of those issues would have been non-existent had I 'RTFM' (Read the Manual). I'm not much of a social networking person (my Facebook page has one purpose: To access Tennis Warehouse deals), so I didn't share any data that way. But going into the swing library was easy enough, and the data was presented in a clear & concise format.​
    What did you like about the app?
    So far, I'm really liking the 3D serving graphic. The estimated MPH is a bit off (I know I don't hit hard serves, but I'm pretty certain they're faster than 44MPH...), but the swing motion & contact point are real nice. It really gives you the ability to see your swing. And the 'compare' feature is also nice since an instructor can record their own 3D swing, then hand the racquet to the student & compare the two.​
    What did you dislike about the app?
    Nothing, really. For me, a true test of a good UI design is 'can I get to most everything without reading the manual', and I was.
    I believe the app crashed on me only once, and that was before the last update.​
    Did you find the data you received from the app useful?
    Again, the 3D swing feature, and the compare graphics are possibly the most useful feature. Granted, the speed/spin numbers were off, but I wasn't that interested in those numbers. I can get more from seeing my stroke than estimating spin/speed. For ground strokes, I did an experiment where I set the ball machine to feed me exclusively forehands. The data came back 60/40 forehand/backhand. I did the same for backhands, and it was 80/20 backhand/forehand. I'm not sure if my 'spinning' the racquet between swings messed the sensor up or not, but I'd expect it to be a bit better counter when I'm hitting exclusively one of the other. Speed/sin estimates seem off as well.​
    Any additional comments/suggestions?
    There has to be a better way to attach the sensor. Maybe somewhere inside the throat? Kinda like a lightweight webbing of some sort? It might affect the swing a bit, but most balance points are near there, so maybe it wouldn't be that noticeable?

    I would also like to see the 3D feature expanded to forehand & backhand. Personally, I could get way more by seeing the path of my stroke, as opposed to swing speed and spin potential. Sure, you can record it w/ a video camera/iPhone and see it, but you can't easily overlay it w/ someone else's swing. Coaching a high school team, I can see the benefit when I'm telling the kids to 'drop the racquet head and finish over the shoulder' if I can have them swing, then I swing, and overlay the two to give a visual.​

    As always, thanks for allowing me to take part in this test.
     
    Last edited: Jun 23, 2014
  23. mikeler

    mikeler G.O.A.T.

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    I'm surprised your serve even registered that high! :twisted:

    Seriously, that is not right. The last time we played you had a lot of heat on your serve.
     
  24. dode

    dode Rookie

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    One thing that didn't work for sure was putting the pro mount on my Volkl C10. I have some different adhesives that I am going to try, but the included tape definitely would not stick to the volkl butt cap.

    John
     
  25. mad dog1

    mad dog1 Hall of Fame

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    i can definitely see an issue if it's the soft silicon volkl butt cap.
     
  26. kimguroo

    kimguroo Hall of Fame

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    Actually I found facebook, twitter and email integration today just swipe to left.
    Now I can post zepp result on those ^_^

    I did about 2 hours drills and spent decent amount time for Valleys. Seems like it counted as slices :confused:
    Hope zepp will be able to differentiate between valleys and groundstrokes soon.
     
  27. gzhpcu

    gzhpcu Professional

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    I get roughly the same readings. It keeps showing slice on the forehand though I hit mostly topspin. The mount is correct.
    On the 3D serve, sometimes the swing path is really weird, going off the screen (way too high, way too in front, way too in back...).
     
  28. gzhpcu

    gzhpcu Professional

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    Same here. I keep getting 10/10 spin on normal serves, and racket head speeds between 35 to 80.
     
    Last edited: Jun 13, 2014
  29. gzhpcu

    gzhpcu Professional

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    It can't because there is no configuration parameter for the racquet.
     
  30. Shroud

    Shroud Hall of Fame

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    For those experiencing inverse spin numbers, have you verified that the sensor is accurately tracking forehands as forehands and not backhands?

    Its possible if these are reversed, the spin numbers will be off too.

    I had really low spin numbers when hitting nothing but kick serves. But it was confusing BH with FH and things were reversed.

    I need to check if orientating the sensor correctly fixes that (the picts are wrong in places and maybe the sensor is oriented wrong?)

    Said another way, if the sensor is oriented wrong and readings are reversed, then the spin number for a flat serve should be 10/10.
     
  31. mad dog1

    mad dog1 Hall of Fame

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    i have verified that my sensor is accurately tracking fh vs bh. the way i did it was to perform a short rally session where i only hit FHs followed by another short rally session where i only hit BHs. initially after reviewing the results of the BH session, i was a bit confused because there were a few FHs sprinkled in. then it dawned on me that the zepp records the starting feed as a forehand if you're feeding the ball w/ a fh stroke. also if you pick up balls off the court with quick strike of top of the string bed to the bounce the ball up off the ground, those also register as FHs.
     
  32. gzhpcu

    gzhpcu Professional

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    Have any of you experienced weird trajectories now and then on the 3D serve feature? Can't figure out where they come from... :confused:
     
  33. TripleB

    TripleB Hall of Fame

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    Tennis-Warehouse,

    I serve left handed but play right handed...how (if it does) does this affect the data I'm receiving from the Zepp unit?

    Thank you!

    TripleB
     
  34. gzhpcu

    gzhpcu Professional

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    You configure Zepp stating whether or you are left or right handed. You have tracking mode for strokes or 3D serve mode. You have to connect to the Zepp sensor to change mode. I assume you will need to change your settings accordingly when selecting the play mode.
     
  35. kimguroo

    kimguroo Hall of Fame

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    New Babolat butt cap might be the best option to use pro mount.
    I removed top part of butt cap which is thin then put pro mount with glue.
    After that the surface of butt cap is smooth so it's much better to stick.
    I changed prince racket butt cap to babolat butt cap. Now it's easy to exchange between rackets.
    [​IMG]

    I wish I have 3D printer to make better mount system T_T
     
    Last edited: Jun 16, 2014
  36. gzhpcu

    gzhpcu Professional

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    The question is whether or not anybody testing the Zepp sensor is satisfied with the figures provided. If not, what is off the mark?

    I'll start:
    • Forehands marked with mostly slice, whereas I hardly ever hit slice.
    • Trajectories on 3D serve now and then weird (shown going all over the place).
    • Spin value on serve is always 10/10.
     
  37. Shroud

    Shroud Hall of Fame

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    Kind of.

    I was getting slice forehands but I hit slice. Though one session I hit nothing but top and it registered some slice. It was accurate I think since I was starting off rallies with a slice or flat shot.

    Yes some weird trajectories on occasion. Not sure how I got my racket 4 ft into the court as part of the take back. But most work great. Did anyone notice you can rotate the view to view from all angles including above?

    My spin serve was 2-3 though I am pretty sure my sensor wasnt oriented right so who knows.

    I'll do some testing hopefully this week.
     
  38. Shroud

    Shroud Hall of Fame

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    on the 3d mode, did anyone notice the "compare" feature?

    It over laps your 3d swing with a PRO (doesnt say who) and you can see how different they are.

    THough I doubt my mph is faster than a pros which it said it was.

    What was striking is how fast their swing was to mine. Yikes its super fast.
     
  39. julian

    julian Hall of Fame

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    Swing path off the screen

    The problem with "going off the screen" can be fixed reasonably easy if
    there is no concern about computing time spent.
    In general it maybe computing intense fix.
    I believe that the problem is a bit hard to debug if no video of a shot
    provided by a user.
     
  40. julian

    julian Hall of Fame

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    Algorithm

    I guess the current algorithm looks as follows:
    1.find say,100 points of the trajectory
    2.fit those 100 points to the screen
    3.connect neigbouring points via a spline curve

    The problem (one of couple possible ones is) the spline curves maybe out
    of the screen even if END POINTS are "in the screen"
     
  41. Shroud

    Shroud Hall of Fame

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    Firmware update

    Look at the app store, there is a "Sensor firmware update to improve 3d swing capture"

    Wonder how it is different.
     
  42. gzhpcu

    gzhpcu Professional

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    Using a spline curve for a number of points determined by sampling points could be a problem where the trajectory of the racket radically changes direction.
     
  43. gzhpcu

    gzhpcu Professional

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    This could occur when there is a radical change in direction, that the spline curve overexagerates the trajectory...
     
  44. TripleB

    TripleB Hall of Fame

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    Location:
    North Carolina
    Tennis experience/background: I’ve been playing tennis for 41 years (currently 47 years old), played high school tennis as well as intramural tennis in college, currently rated a 4.0 but spent several years at 4.5, typically play at least twice a week during most of the year and about 4 times a week during the Summer months, before Fall of 2012 played singles 85% of the time, coached high school tennis for four years

    Describe your playing style (e.g., baseliner w/heavy spin, serve & volley, etc.,): due to microfracture knee surgery two years ago I play doubles (4.0/4.5 level) approximately 95% of the time, even in doubles I prefer to be at the baseline, I use heavy spin (both topspin and slice) on most of my shots, my best shot is my backhand while my weakest shot is my first serve

    Current racquet/string: Volkl Organix 10 325; Volkl Cyclone 1.20mm mains at 51 pounds and Volkl Synthetic Gut 1.25mm crosses at 53 pounds

    Which mount did you use? Was the device easy to attach to the racquet? I used the Flex Mount because if I were to use this through the years I would like to be able to change between racquets (even going from racquet to racquet while demoing racquets from T-W) easily and also be able to compare the results immediately. It was extremely easy to attach to the racquet and the arrows on the mount helped to make sure I had it on correctly. Once I had it attached to the racquet I just put my normal overgrip over it and the rest of the handle. If I knew I were going to be changing it back and forth between racquets I would forego the overgrip. The lights moving across the unit every four seconds, letting you know it’s collecting data, is extremely helpful.

    Given its weight along w/location on the racquet, was it a hindrance? Without the Zepp my racquet weighs 349 grams (12.3 ounces) and is 9 points headlight; With the Zepp my racquets weighs 368 grams (13.0 ounces) and is 14 points headlight (from base of racquet). I could tell that it was on there because sometimes when I used extreme topspin my pinky finger is basically hanging off the butt of the racquet. But to be honest, it didn’t bother me as much as I thought it would. The feel of the unit being on the end of the handled bothered me more than the increased weight of the unit or the change in balance that it caused. Overall not a hindrance, but if I were playing a league match for the championship, I would not want the device on there because it does make me grip the racquet differently on some shots.

    How easy was it to upload, view, and understand the data on the app?
    First let me say that putting the app on your mobile device (in my case the Samsung S5) takes about 7 seconds and is effortless. Data is amazingly easy to upload…just tap on the Zepp app, the Zepp is recognized through my Bluetooth, and the data is uploaded automatically. The data is easy to view and I like the fact that there is a calendar that organizes your data so you can tap on any date, any session, and bring up the data quickly. I’m not sure how the data could be any more understandable…forehand/backhand/serve…click on one and it gives you the breakdown on topspin/slice/flat. Switch over to power and it gives you the overall average and maximum power. Then it breaks the information down by shot type and also gives you the average and maximum power for each shot type. The 3D Serving Practice playback takes a couple times of viewing to understand the data being shown but once you realize what it’s showing you it makes sense. Even for the non-tech minded person the information is clear to view, easy to understand, a breeze to navigate through, and offers some good depth.

    What did you like about the app?
    I liked the fact that it was easy to install and once you installed the app it walked your through the set up of the Zepp in a very clear manner. I loved the fact that once I clicked on it the app automatically uploaded the data through my Bluetooth. I also liked how much data it gives in an understandable manner without being cluttered with meaningless information.

    What did you dislike about the app?
    To be honest the only thing I would want to change about the app is for it to have the option of choosing a different hand for serving and groundstrokes. I play right handed but serve left handed and the app made me choose either right or left. I know that there are not many of ‘my type’ around (only 2 in my area that I know of) but it would be a nice option to have so I didn’t have to change my settings when I went to serve. Other than that I thought the app was excellent.

    Did you find the data you received from the app useful? Please explain your answer.
    Yes, the data I received from the Zepp unit and its app was extremely helpful. A couple situations, other than the obvious ones already mentioned in other reviews, where I could see me using the Zepp:
    - to help me become more aggressive with my returns and the rest of shots; a lot of the time I tend to slice my returns back just to get the doubles point started (without getting my partner killed); I also tend to slice a lot of shots with my backhand because it’s been my favorite shot for 40 years; I could use this unit and the data it provides to reduce my slice percentage and work on getting my topspin/flat shot percentage up
    - to help start adding variety of shot to my son’s (7 year old) game as he learns how to hit a wider variety of shots because I can show him what percent of the time he hits each shot
    - the 3D Serve Practice made me realize the importance of a consistent toss on my serve; loved comparing two of my serves side by side and seeing what difference there was between a weak serve and a powerful serve
    - I typically play the ad side since I usually have a better backhand than my partner; I would like to use the unit to see if I actually hit more backhands than forehands on that side of the court

    Any additional comments?
    I would like to address the accuracy of the data: I found the data provided through the Zepp unit to be pretty accurate. Not only did I use the Zepp but I also put it on my 7 year old’s racquet and hit balls with him. I did this to see how accurate the unit was: I could dictate how many forehands and backhands he hit and I could also check to see if the power the data showed dropped, like it should, since he doesn’t hit the ball as hard as his old man (yet).

    It’s not 100% accurate as far as forehands and backhands. In one session I hit 32 shots making sure I hit the exact number of forehands and backhands. It registered 44% forehands and 56% backhands. Not a huge difference but a difference none the less. During that same session I hit the same number of topspin and slice shots: Backhand it registered 55% topspin, 25% slice, and 20% flat; Forehand it registered 41% topspin, 41% slice, and 18% flat…overall I would say pretty accurate.

    When I included some serves with backhands and forehands it didn’t pick up my serves quite as well as my groundstrokes. In one outing I hit serves right at 25% of the time but it only registered 11%. I will say that part of the problem may have been that I serve lefty and play righty…but in the software I had to choose either right handed or left handed (and chose right handed).

    I will admit I was very skeptical when I heard about the unit and signed up for this playtest…but the Zepp Unit and the data it provides has convinced me that this in fact is accurate and can be used in a variety of ways (many I had never considered until I actually used the unit) to help improve your game! I really loved a lot of things about the Zepp and could see myself using it at least once a week to help me concentrate on my shot selection and to improve many difference aspects of my game.

    Thank you Tennis-Warehouse for allowing me to be part of the Zepp Tennis Sensor playtest!

    TripleB
     
  45. gzhpcu

    gzhpcu Professional

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    A new update was just released with improvements to 3D serve trajectory, will try it out on Friday...
     
  46. julian

    julian Hall of Fame

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    Couple of remarks


    Hi,

    Couple of very trivial remarks:
    1.There are two points of trajectory when a direction of velocity is changed "drastically".
    You may see the same for a motion of a pendulum.

    2.I would advise,if I may,to report a problem of trajectory going out of screen
    to the support of Zepp Labs
    Probably a video of a serve will be needed to debug the issue

    3.There are two new reviews in
    http://www.tennis-warehouse.com/feedback-BPLYPD.html
    to compare with.

    4.The patent for the Zepp sensor
    patentimages.storage.googleapis.com/pdfs/US8725452.pdf
    However it does NOT put any light on the issue of a trajectory going "out" of a screen
    Regards,
    Julian
     
    Last edited: Jun 18, 2014
  47. gzhpcu

    gzhpcu Professional

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    I reported the problem to Zepp labs. Will try upgrade Friday. If problem persists, they have asked me for screen shots...
     
  48. julian

    julian Hall of Fame

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    Screen shot?

    Do you have a screen shot for this particular problem?
    Just to compare with a problem of one of my students here.
     
  49. gzhpcu

    gzhpcu Professional

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    Unfortunately, I deleted all of the history, since it was not helpful. Will do so Friday when I get new data if the problem persists after the upgrade...
    But essentially it was at the very start of the motion it showed a forward swing going off the screen, and another time at the trophy position going straight up and out.
     
  50. julian

    julian Hall of Fame

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    Couple comments

    Couple comments:
    1.Both points you described are called,as you know,"turning points"
    (no jokes about my English,please)
    2.The "spline approximation" is fuzzy for "turning/turn points"
    3.I have read a patent description-
    to get a trajectory one has to integrate over "velocity values"/"spline curve"
    4.Potentials problems are expected as a combination of #1,#2 and #3
     

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