Trace / The Action Sports Tracker

[gator1]

@dlokshin‌ Thanks for the clarity. Does the satelite signal set the 5 hz update limit? If not can we buy ten recievers and clock them to update in series? Or just ignore. You've probably already answered more questions then you'll get profit.

[Horton]

@dlokshin‌ in case you are not familiar this is what @Kelvin‌ is talking about

[Horton]

@dlokshin‌ someone is going to ask about this too

 

[MattP]

@Horton‌ you let @dlokshin‌ watch your mediocre slalom skills and not your Sr. World level tricking?! You are an ex Open rated jumper and you did not share the world of 3 event?! Thats just sad.

[Horton]

@mattp that is Masters Men level trick skiing I will have you know. (yes my handle tricks are embarrassing but my toe pass is almost what it was 20 years ago)

[dlokshin]

@gator1‌ No, and the chip we use can go higher. If you go higher you loose accuracy. There is a way to keep most of the accuracy, but none of the chips on the market implement this method (and we're not in the business of making our own GPS chips)

 

@Kelvin‌ Yes, if we spent time on this, we could definitely do it and have spent enough time with wakeboard data to have confidence in that. As I was explaining to John, though, we're a small team and believe very strongly in focus.

 

That being said, we have an API (developers.traceup.com) and I would guess 100 hours of work would get you to a place that this forum would be excited about. Just simple stuff like:

* How many total "passes" you did around the course

* How many turns in each pass

* Total distance traveled

* Overlayed maps so that you can see your consistency (one of the biggest things I notice about John's data. When we look at gold medal skiers, for example, differentiating one run from another is nearly impossible. You actually have to dig into the sensor data)

* Improvement

* etc

 

@Horton‌ Can I somehow set this up so that I get an email notification when someone @ me?

[MattP]

@dlokshin‌ Go to your profile ->Edit Profile-> Notification Preferences

 

Last time I looked into the API a few months ago it seemed to only support a Social Media type interface. Have y'all expanded the documentation to support development for more specific sports?

[Horton]

@dlokshin‌ yes I will tweak your settings later today (might be tonight - hard to do from my phone)

[dlokshin]

The visits endpoint is mostly data:

 

http://developers.traceup.com/Endpoints/Visits.html

[Horton]

The plan is to get as much data as possible this coming weekend.

 

@Colebrah‌ you ready? I have a mount for your ski.

[MarcusBrown]

@Horton @dlokshin‌ I don't know where to start.

 

This. Looks. Badass!

 

Pretty much every single theoretical principle (is west coast better?....or should we call Schnitz and get his notes on Coordinates) that has been discussed in the past 15 years can be tested, to some degree, with Trace.

 

For someone who feels like they had a hand in completely changing the conversation in slalom skiing, from "try what Mapple does...try what Rodgers does...try what Coxy does..." to "we wanna go faster, be more efficient....here's what physics says you should do to make that happen", I feel like its simply the next level of exploration: we can now "TEST" these ideas, to a certain degree.

 

How accurate is this device? And to what degree can we test different Hypothesis'? Don't know yet, but I'm intrigued as hell.

 

Let me know when you need my address guys....I'd like to strap one to my dreads and see what kinda accelerations I can achieve outta 2,4 when I drop my armpit in the water and dread-whip myself in the face.

[mwetskier]

theres an obvious delay between the video action and the mph readout as @Horton noted but what i found most interesting is a momentary minimum speed of 21-22 mph and a maximum of 52 mph at -35. Would love to see the swings produce by nate smith. my bet is a higher minimum and a lower maximum than most other skiers.

[Horton]

@MarcusBrown I could not agree more. I want to know why the dreads hit you more at 2/4/6 than 1/3/5. Now that I think about it when I wear my hair down I get the hair whip at edge change going to 2/4 also.

 

Seriously. Yes! Data to show what you have been talking about all these years.

[Skoot1123]

There is part of me that says what is needed is a localized mapping of a lake and course. Couple this with a base station you can probably get the accuracy you need. Think about it - what do farmers in the 21st century do? Yes, GPS steering and tracking - planting and harvest. What about construction? ABSOLUTELY. In fact for the construction industry it is maybe even more critical, and they are doing this with scrapers that - when fully loaded - weigh between 26,000 lbs and 270,000 lbs. Oh yes, they can travel between 24 - 33 mph. While it may not be at the speeds we see, it tells me that there is a way that it could be done.

 

The "trick" I think Trace is trying to achieve is doing the above without a base station and the local mapping that would need to be done. Being able to achieve this would be without a doubt one of the best things to happen to sports. Imagine how much data we could have an analyze then?

 

This is only the beginning of "advanced" statistics. Bring it!!!

[dchristman]

Underlying technology aside, here's what I envision for an interface with a sensor on the pylon, handle, and ski. The tracks would be overlayed on a zoomable grid with course. Track width would be scaled appropriately to represent speed (faster=thinner). Move a pointer over any track and it displays the corresponding point it time on all tracks with data. A fixed-length line representing the rope is displayed between the pylon and handle point. The line would extend beyond the handle point in the case of slack. A synchronized video would display the corresponding frame.

Forgive the crude drawing. I'd like to create a demo interface to play with, maybe over the dark days of winter...

 

 

 

 

[Horton]

Here is a link to some GPX data that I did not know I had. Geeks GO!

https://www.dropbox.com/s/1u6yjddbb3pmrjt/john-helmet-3.gpx?dl=0

[Horton]

@dchristman‌ I like iit

[dchristman]

 

@horton Better, but still kind of disappointing :\ I guess we just can't expect too much from the gps data alone.

 

[MattP]

@dchristman‌ what program are you using to process the data?

[dchristman]

@MattP‌ you can upload GPX files to www.gpsvisualizer.com and output to various formats.

[MattP]

@dchristman‌ ah yes I know the site well. (Geography minor here)

[Horton]

Well... idk

[Edbrazil]

Would be interesting to put this device on a high-level Open jumper. Probably not on a ski,

as that would be subject to some brutal impacts. Maybe strapped around waist somehow.

One very interesting item would be to find out just how high the jumper gets at the peak of

flight. I'm thinking around 28 feet off the water, plus or minus.

[mwetskier]

@Edbrazil -that should be easy to calculate from the right photo. down course looking back at the jumper from a good distance you would have an object of precisely known height from the water surface sort of under the skier. some error due to the jump being farther away when the skier reaches maximum height but probably still get a pretty close estimate.

[DefectiveDave]

@dchristman,

 

In some areas it might be possible to get more refined GPS data using real time kinematics (RTK).

 

http://en.wikipedia.org/wiki/Real_Time_Kinematic

 

Of course it relies upon a local base station, but many of these are already available through local real time networks (RTN) in several states. If you have ideal conditions you can get around 1cm accuracy with these systems. Of course, said clients for RTK tend to be significantly more expensive than commodity GPS. However, the cost might be coming down:

 

http://store.swiftnav.com/

 

Still not something I would want to risk losing in the water.

[dchristman]

@defectivedave now that is exciting! The price isn't really that bad. I wouldn't see it as a personal purchase like the Trace - a club could realize a reasonable cost per person.

It says "50 Hz position/velocity/time solutions", 10x greater sampling rate than the 5Hz @dlokshin‌ mentioned for the Trace. Of course this isn't a finished system ready to attach and go, so there would be work to be done water-proofing and powering the modules. I like the idea that it's open source...

[ToddL]

@dchristman‌ - keep in mind that some of those trace lines are the skier going top to bottom and others are the skier going in the opposite direction. I quite certain I can guess which is which. smooth, rounded approach to the buoy, tighter arc after it...

[dchristman]

@toddl yes, you can clearly tell which direction he was skiing. I guess my disappointment in that particular "good" data stems more from alignment with the course and is compounded by the fact the Trace is on @horton 's head rather than the ski. On some balls it looks like he would have to be 20' tall to get his head that far inside the ball-line. The tracks look to be shifted East a bit and maybe a bit narrow (probably because it's on his head). I'd really like to see simultaneous handle and ski data.

[Horton]

@dchristman‌

 

Will get ski data this weekend. Will continue working with @dlokshin‌ to find best use of Trace

[Edbrazil]

@mwetskier: Did something like that in the days On The Tour. Before the big-big skis, but when

top jumpers were going 220's. Figured about 27 feet skis to water at peak, best of my recall. We were staying in a hotel with an atrium. Went up to one of the levels, and unreeled my measuring tape with a weight on it. Got 27 ft. or so to the floor we stood on. This was the 4th level of the hotel, and the people with me didn't believe it.

[escmanaze]

This is definitely some of the coolest waterskiing video I have seen in a long time. I would love to even just see like a graph with time as the x axis and speed as the y axis. The possibilities for this kind of technology just seem endless.

 

Now I want to see a 36 mph run on it. That top speed of 51 mph would very likely turn into 55 before you know it.

[Horton]

@escmanaze‌

I will get some 36 mph Sunday. @Colebrah‌ should be able to peg the speedo

[dlokshin]

Just wanted to pop back in. Awesome discussion back and forth. Let me know if you all need something else.

[bbirlew]

@dchristman, @escmanaze,

Here is a sneak peek of something I've been working on for a while. It has a ways to go, but some of the data so far is kind of cool. It's a little android app to run on a phone or tablet.

 

Basically I map a course similar to zero-off, and then parse out the pass data and rotate it all to plot it on an x/y plot. It saves all the info into a database so you can compare sets from different people skiing different courses. The first plot is comparing @Hortons first and third passes, and the second one is showing his speed overlaid on his position plot.

 

The app allows you to configure different skiers, skis, etc, then you can manually enter your boat speed/rope length/zero-off setting when you upload the data from the sensor. You can use it as a ski log to pull up the details of your fin settings, zero off setting, notes, etc for each pass. You will also be able to do queries of the database to find out how many passes you skied, how many 38's you ran, or how many balls you rounded for the year, etc.

 

The button that says "pause" lets you re-play the pass with the circle showing the skier and boat position (well... The boat is just the ideal boat position, calculated based on the speed you are skiing, the rope length and the time you go through the gates...) You can also select any point and zoom/pan/etc to get more detail.

 

Eventually, I'd like to add:

- graphic to show the roll angle side to side and front to back of the ski

- sync up with video so you can pick a spot and pull up that video frame

- highlight interesting points on the plot (min/max speed for example)

- incorporate strain gauge data

- automagically calculate the boat speed from the ski data for one less thing to enter manually

- add a scale to the speed data to make it more clear

 

@dchristman, similar to your idea on varying the line width based on speed, I did try changing the color of the plot to show speed (fast = red, slow = blue for example), but it just wasn't clear enough on the plot to see what was going on...

 

I'd love to hear you guys thoughts and get some feedback. (I also need a name for it!)

Hoping to have something available for spring, but it's just a spare time project so its slow going...

Cheers,

Brad

 

 

 

[dchristman]

I think I was too quick to dismiss the helmet mounted unit... that'll be the one with two-way communications and the "training" electrode. Aaaaah! The Matrix is reaching for the sanctum of the slalom course!

[MattP]

@bbirlew‌ looks like you heve been holding out on us. Cool stuff. Keep us updated.

[SkiJay]

Nice work @bbirlew‌! I love speed traces. At a glance, this one shows that:

 

- max speed is not behind the boat but just past the second white water (with a good connection)

- these on-side cuts were more effective than the off-side cuts

- the ski may be landing in the off-side pre-turn with a bit too much tip (brief extra deceleration not present on the on-side)

- speed at the end of the pre-turn right at the ball is still quite high (about average speed or 34 mph)

- speed exiting off-side balls is significantly higher than on-side turns (is this due to more smear during on-side turns or higher entry speed from the great on-side cuts?)

- acceleration starts fairly abruptly (pointy troughs in the speed trace)

- acceleration is smooth and progressive

- the turn around 5 ball carried the most speed of the pass and required the least acceleration to get to the next ball

 

Some of this is info that's not really obvious with video review, and overlaying it with traces from pros would be awesome.

[Horton]

I was charging my Trace for tomorrow and found this file. I have no idea if this is too raw to be used but if you want a ton of misc data here you go

[Mateo_Vargas]

What ever happened to good old fashioned bread crumbs?

[mwetskier]

@Mateo Vargas -theres a bird interaction problem associated with that technique.

[dchristman]

@horton no track data in that file... it's looks to be a log of functions as they are activated on the device and satellite acquisition.

[Horton]

Hmmmm

[dchristman]

Lines like this are found in found in the log file:

 

370323: FLASH TASK: Data file 0:\Trace\data-141028-00-47-45-000.trc created.

 

I assume those are probably proprietary binary files.

[dlokshin]

Yup, log.txt helps us trouble shoot when someone's Trace goes KooKoo.

[dchristman]

@bbirlew‌ The name for your app should be IPA ...the Instant Pass Analyzer. "Skiing poorly? IPA can help!" (please use responsibly)

[bbirlew]

Great observations @skijay. Ya, figuring out what all the data means is going to take some time and someone with more skiing knowledge than me!

As a programmer I'm trying to find the best way to present it to make it meaningful. One of the keys was certainly to transpose it onto an x/y coordinate space so that you can compare your data on your course with others skiing at different locations.

Any hints on how to make it more useful are always appreciated (certain points to highlight or different views of the data).

 

[MattP]

@Horton is the GPX data you posted from your head mounted Trace or from a ski mounted? Also did you run full pages during that data capture?

[Horton]

The data from 2 weekends ago was head mounted.if you dug around and found last week's data it was a party foul.

[MattP]

@Horton it was the data you posted on Nov 12th. The data looks alright it knowing where the device was placed will allow me to figure out what is going on. Honestly head mounted data is useless for determining ski path. I'm looking for ski mounted data if you have any.

[Horton]

Helmet