Splasheye

I thought I'd share some research video I took last month.

Drone is a DJI Mavic Pro

Sitting at 800 ft directly overhead center of course and looking straight down for slalom

For jump its sitting at 250 ft over the landing area looking straight down.

After you set its position the first time the Mavic allows one touch return to base (for battery swap out) and then one touch to get back to the exatc same spot in the sky

The process takes about three minutes

While the battery life (25 minutes hovering) is not yet enough to be really practical I think this will have real possibilities in the future

One judge?

Realtime skier analysis?

Jump measurement without the camera towers?

Plus it's cool.........

The original high-res videos are available for download if anyone wants them

http://www.splasheye.com/drone

If near Dublin check out Golden Falls. About 40 minutes from city center. http://www.goldenfallswaterskiclub.com

@eleeski IWWF rules are where I would expect them and not what I would consider hard to find.........

Under resources on the iwwfed.com site (full rulebook)

and on the iwsf.com site first entry under Rulebooks

(full rulebook)

While I don't doubt that that course is off.....I've lost count of how many times as homologator and TC I've had to explain to a judge that a course that LOOKS way off is actually well within tolerance. To illustrate I use pictures like these

The slalom ball is EXACTLY where it should be

One gate ball is maximum length tolerance and the other is minimum length tolerance

A lot of judges will line up the two gate balls and be shocked by how "out" the slalom ball is (in this view it 'looks' to be about 6 feet out of position when it is perfect)

I've seen that pass before and measured it - some of the best driving I've ever seen at that short a line - and I've seen a lot of EC video

Summary (in cm, divide by 2.54 for inches)

Average Deviation at Buoy 1: -0.086

Average Deviation at Buoy 2: -7.887

Average Deviation at Buoy 3: 2.738

Average Deviation at Buoy 4: 2.262

Average Deviation at Buoy 5: 3.370

Average Deviation at Buoy 6: -0.484

Cumulative Deviation at Buoy 1:(20) -0.086

Cumulative Deviation at Buoy 2:(28) -7.973

Cumulative Deviation at Buoy 3:(35) -5.235

Cumulative Deviation at Buoy 4:(40) -2.973

Cumulative Deviation at Buoy 5:(45) 0.397

Cumulative Deviation at Buoy 6:(49) -0.087

To answer @Wish first question - if you can't see the pylon you do the best you can - in this case splitting the center windshield panel. Yes you are measuring a point 2-4 feet in front of the pylon so if the boat is wagging a lot around the pylon there is a small discrepancy, but you can see in the frame-by-frame when that is happening and you make allowances

The cumulative deviation will normally catch a driver intentionally helping or hindering the skier. What it won't catch is a driver driving straight but off center. A driver can drive 6" to the right all the way down the course and get an in-tolerance pass with a zero cumulative score. Not sure what that feels like to a shortline skier though! That's why SplashEye EC adds in some extra measures of a drivers performance as an aid to improvement.

I did it about 20 years ago. Went from LFF to RFF. Took about a season to reach the same tournament PB - 4@32 36mph. Although it technically looked better it never felt truly comfortable and I later went back to LFF

@Than_Bogan already working on it. Wide angle megapixel camera mounted on the windshield. Digitally tracks and zooms in to the skier providing video tracking and hopefully as a bonus proper speed/acceleration/location information.

Like most WaterSki projects I expect it will take a huge amount of time and will sell in tiny numbers at a price that doesn't come close to covering costs yet which makes people complain about how expensive it is :smile:

@Roger Yes the new release in the Spring will overlay the tracking information on the recorded video for each pass

Donal

www.splasheye.com

Thanks @klindy. But I must take issue with saying that sensor data or any other GPS app does a great job with positional data. If I capture data with my phone sitting on my desk the GPS coordinates will frequently change by 0.00001 degrees. May not sound like much but from what I can work out that is about 4' of absolute position from a stationary object (when we are looking for <1")

@BrennanKMN There are some great articles out there about how hard it is to compensate for accelerometer errors to generate an accurate velocity or location https://goo.gl/Mp7uRc

These are people who sell 'low cost' accelerometers and their summary is "In general, accelerometer-based position and velocity estimates from low-cost sensors (hundreds of US dollars instead of tens of thousands) are very poor and are simply unusable."

@klindy I like to think it's a LITTLE bit magic that for the price of a couple of slalom skis you can have a system that automatically plots the deviation of the boat accurate to 1/2 an inch at a distance of 1500' and then sends the plot of the pass to your mobile phone AND allows you to gather the data by skier/driver/boat/tournament.....but then I'm biased :smile:

www.splasheye.com

Not sure about deep 38......

http://www.solowatersports.com/?p=1283874021

Long story but goes to show what you can do with an obsessed 15 year old boy (me) an understanding Dad, no boat, an old pair of wooden combos and access to a long, clear stretch of canal......

1965 Massey Ferguson TO35

@lpskier The rules (at least the World rules) are pretty clear on the question of intentionally using tolerances

1.11: Tolerances

All tolerances are to allow for human error and the intentional use of tolerances by tournament

officials to improve skier performance will not be tolerated. In any activity involving the

performance of an official where a tolerance is involved, it is the official's responsibility to attempt

to be as close as possible to the actual specification.

Slalom buoys are one of the very few places where the recommended value is not in the middle of the tolerance but rather right at the very low end.

Hi Ed,

If the skier is accelerating at the bottom of the ramp (and with the edge and load that the top guys have at the bottom they can only be accelerating) it stands to reason that their speed will continue to increase as they travel up the low friction ramp. This was borne out with GPS tracking I did some years ago with the best of the best. Maximum speed was reached at a point several metres AFTER the top of the ramp. Speed is the second graph - directly under the location graph. The ramp is represented by the two vertical lines

Donal

@ski6 contact me directly info@splasheye.com

Audio slalom has been used for years for visually impaired athletes in competition and training.

http://audio-slalom.be/

@kelvin the rule on maximum field of view or zoom factor is the limiting factor. 1920*1080 would comfortably cover 250 feet but the single hd camera would have to be so far back from the landing area and therefore so high over water as to make it impractical at most every site

Donal

SplashEye Premium will automatically measure jumps in three grids on a single computer. SplashEye Core measures a single grid but additional licenses are available for simultaneous use ( $500 including additional USB video capture device ) and for backup use - installed but not simultaneously active ( free of charge )

Donal

Once you get behind the boat you'll find the simple things are the problem!!

I did a similar setup for a World Cup stop in Ireland a few years ago. Load sensor on the rope being monitored by a laptop in the boat on a WIFI connection to a laptop on shore that was driving a step motor with a big wooden clock arm on it showing live how hard the skier was pulling.

Unfortunately on Jodi Fishers potentially winning pass the rope connecting the load sensor to the pylon broke and dropped him in the river- he's never forgiven me

Nice project