Connecting directly to the accelerometer & gyroscope of your phone, a super smart algorithm will calculate your jump height.
Surfr. is the only solution that will measure you jump distance. Jumping far requires different skills from jumping high. So send your kite hard and get up the leaderboards.
Be the Max Verstappen on the water and dominate the leaderboards with new speed records. Thanks to the GPS sensor of your phone this is now possible.
We managed to create an algorithm that doesn't care which phone is used and always performs consistent. Based on our testing of different phones versus each other we found that 98% of all jumps had a difference of less than 50CM and 80% had a difference of less that 30CM. There was no 'higher jumping' or better performing phone: they all performed similar on average.
Live stream your kite session (location and jumps) to friends and family. Or watch your friends on the water and get their jumps pushed live to your device.
Start your session and the Surfr. will automatically keep track of your live location. Now your friends and family can always check out if your still cruising or drifting across the ocean.
Beside the conventional height and airtime leaderboards you can now also compete on jump distance and speed. Send the kite hard and cover more ground. Or reach incredible speed on a hydrofoil, or even mid air during a kite loop.
Having a smartphone (sensors + GPS + Internet) with you on the water creates so many possibilities. More features will be added soon. Scroll further down for our current idea's.
The Surfr. Mount!
Specific designed and manufactured for The Surfr. App. Fits every phone with length between 138mm and 167mm. Width between 65MM and 90MM and height between 7MM and 9MM. This is almost any phone from the Iphone SE 2020 till the Galaxy S20 Plus.
Once you close the mount with the 4 clips the mount is totally closed and water tight. The rubber seal keeps the water out.
The little rubber studs inside the mount will fixate the phone within the mount and also makes sure that big impacts of your board on the water are absorbed as much as possible by the rubbers in order to protect your phone.
3M VHB (GoPro) tape
The mount will be taped to your board with 4 3M pads. These 3M pads are similar to the pads used by GoPro.
Security rope (not on image)
The mount comes with a little security rope which can be attached to the board handle or foot pad.
The price of the mount is 35 euro, excluding shipping costs.
By now smartphones are very well equipped with high quality sensors. The most complex games can be rendered on your smartphone which often use the same kind of sensors. These sensors, accelerometer, magnetometer and gyroscope are actually similar to the sensors found in hardware based solutions. The extra challenge Surfr. had to address was the big variety in smartphones in terms of brands and models. After months of riding and testing we created an algorithm that is insensitive to which phone is used. The algorithm connects to the phones hardware directly without using any software of phone manufactures and/or operating systems. By connecting the app directly to the hardware we were finally able to reduce differences to a minimum. In the end when we compared 2 random phones against each other 98% of all the measurements had a difference of less than 50 CM, 90% had a difference of less than 30 CM. For example: if one phone on the board rated a jump 8.6 meters than the other phone would not deviate more than 30CM in 90% of the cases. Actually in the most cases the difference was less than 10CM.
Yes. We spend a lot of time on this project, and we will continue to do that. In the meanwhile we try to keep our costs as low as possible. What started out as ‘why can’t height be measured with a phone anno 2019/2020’ turned into quite an obsessive goal to tackle height measurements with a smartphone. But yes, we have costs so there might be a small charge in the future. Obviously our costs are way lower compared to hardware device based solutions and therefore the app can still be free and continue to be free for as long as possible but at least for another year, till the summer of 2021.
We’re selling a board mount to make it possible to mount the smartphone on your board, waterproof and secured. (Pre)Order the mount now to make sure you get your mount as soon as possible.
Yes and no.
No: For height related measurements the phone has to be mounted on the board. We spend a few days on trying to get the algorithm to work when wearing the phone around the neck. That turned out to be nearly impossible (maybe it’s actual impossible, we have to do further research for that). The problem with wearing around the neck is that all the vibrations are muted out substantially by your own body. So it’s really hard to detect the starting point and the end-point of a jump.
Yes: you can wear it around you neck and still benefit from GPS related features, such as tracking, speed, distance & live-location.
We tested thousands of jumps where we had about 2-4 phones on the board, 2 WOO 3’s and 1 PIQ. We will probably publish some of the test results later on, but we actually hope that other people will do similar testing as it’s always better to have a totally independent view on this.
The main conclusions from our research though is that the measurements are somewhere between WOO and PIQ. WOO measuring higher and PIQ measuring a bit lower. But there is great correlation between the three when testing 1000+ jumps.
PIQ and WOO both requires an extra hardware sensor. In case of WOO you also need a watch to see the live height. For Surfr. you only need your existing phone.
Surfr. also benefits from your phones GPS and internet connectivity to be able to track your location, speed, jump distance and Live streaming.
If you loose your board you can track it back based on the GPS streaming. Your board will continue to share it’s location as long as there is battery left in the phone. Next versions of Surfr. will also introduce board recovery support, so that other Surfrs around get notified that there is a drifting board.
But yes, it’s possible to lose your board and your phone with it. Only you can decide if you want to take the small risk involved. But you weren’t kite surfing if you where a 100% risk avoiding person right ;)?
We have a few suggestions though. Get confident with body dragging. Kite with a buddy. If you do this the chances of loosing your board are almost non existent.
The final option you have if you’re still worried is to put an older phone in the mount, or buy a cheap new one. You can buy for example the Samsung Galaxy A40, a Huwai P30, Motorola Moto G8 or a Oppo. These phones have all been tested and will cost around 200 euro.
No. The mount is taped with extremely strong tape, and secured with a little rope to a handle or pad.
General phone requirements:
In general the app requires two sensors to be present. The accelerometer and the gyroscope. They need to operate at a frequency of at least 100 Hertz, meaning that the Surfr. app will be able to measure 100 times per second the orientation of the phone as well as the acceleration. This is the case on every new phone you buy, but on older phones you might have frequency below 100 hertz.
Almost any phone has an accelerometer, but sometimes on the really cheap phones there is no gyroscope. You can look that up in the specifications.
Every phone listed is comparable in terms of accuracy and consistency. It’s not the case that the more expensive the phone, the more accuracy.
In wetsuit mode there is no big difference between devices since you turn off the screen it will last for 6+ hours on almost every phone.
In board mode LCD screen will use a lot more battery then Amoled screens. This is because black pixels also use energy on LCD screens (and they don’t on Amoled screens). Most Android phones are on Amoled and most Iphones are on LCD. So in general Android will have much longer battery life then IOS when used in board mount.
– Iphone 6 and up
– IOS 12 and up. If your older Iphone is not yet on IOS 12 you can upgrade it. IOS 12 is available for Iphone 6 and up.
In addition to the general requirements (having a gyroscope and accelerometer) there is a bit more to say regarding the accelerometer. This only applies to Android.
The accelerometer of your phone has a maximum range. This indicates up to how much G-Force it can measure. There are 4 levels out there: 2G-force, 4G, 8G, 16G. Most phones are on 8G or 16G mode. About 10% of Android phones (especially the budgets ones) are on 4G mode. Only very old phones, a few, are on 2G mode.
- 2G: not supported
- 4G: supported. When jumping big you will peak above 4G on take-off and 4G phones can’t register that. The clever Surfr. algorithm we build will still be able to calculate the height but it’s not ideal. So don’t choose a 4G phone if you go above 15M on a regular basis
- 8G/16G: Perfect for Surfr.
So if you want to buy a new phone definitely check out the Range of the Accelerometer as well and choose a 8G of 16G phone. This is not listed in the specs of the manufacturer but based on the phones that have been registered on the Surfr. app we are keeping a list of this, which you can download here to help you choose a new or second hand phone which is perfectly compatible with Surfr. :). Please note that this only applies to Android since every Iphone 6 and up are all on 8G mode.
Note: you can check the range of your phone if you want by installing the app Sensor Kinetics then look for Accelerometer. There is a property Range there. Divide the value by 9.81 and you will get the amount of G-Force. Make sure to install all updates available for your phone as well. Since the maximum range is determined by software and not by hardware upgrading might improve the range of the sensor as well.
My name is Herbert Vuijk. Surfr started for me at the end of 2018. After a few days I realized this project was quite complex, probably one of the most complex projects I was ever involved in. I didn’t have enough time beside my normal work to continue on the project. Until the end of 2019. Till then I was co-founder/partner in a few IT companies which I left around August 2019.
After taking some time off I found new energy to combine two of my biggest passions: programming and kitesurfing. After a few months of development and testing Surfr 1.0 is the result of that. If you want to read more check also my personal blog, www.firekiter.com.