Transferring the Base Video

The Base Video is at the heart of all timekeeping in both Photo and Video finish and contains everything that is needed to recreate a finish with full accuracy. It can therefore be convenient to move it to another iPad or Macbook for marking to offload the finish line device. This post goes through different ways to transfer the base video, especially a very convenient direct transfer to a Mac.

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Start Sender zero testing

A so-called zero test ascertains that all your connections and synchronizations are working properly. This test is especially important if you are using the cloud mode where the devices are not synchronized directly to each other and you rely on the quality of the cellular network. The IAAF Photo Finish Guidelines also recommend that you do a zero test. This post is a guide on how to conduct a zero test on-site, both with a starting gun and without.

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Speed and agility testing

Testing the top speed of an athlete is important in many sports. To able to accurately measuring a 10-20 m flying sprint is therefore useful. There are also many events where start, stop, and turn agility is important, for example, football (both kinds), basket, tennis, etc. The shuttle is, therefore, also a handy test. This post gives you some tips on using Flying Sprint and Live Finish for testing and what accuracy you can achieve.

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Setting up a staggered start

A staggered/interval start has long been common in several sports like cross country skiing and cycling (tempo events). In skiing, it was actually the norm up to 30 years ago. In other events like cross country running, it has been less common, but current demands for social distancing has lead to an increased interest in individual or group starts. This post will therefore give you some tips on how to run a staggered event. You can use it in both Photo and Video Finish, but these kinds of events are usually best handled in Video Finish.

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Calibrating the start sound

SprintTimer can act as a starting gun, either by selecting a start sound, e.g. a shot, in connection with the hand start or by using the self start. Accurate timing requires that the sound is played at the same time as the clock starts. SprintTimer, therefore, uses low-level sound routines to minimize the latency when playing the sound. The delay is usually a few hundredths of a second. But the latency may increase quite a lot if you use a Bluetooth speaker, and delays of 0.1 s – 0.4 s are not uncommon. The purpose of this post is to give you some tips on how to mitigate that problem.

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SprintTimer accuracy

The most important feature of a timing app is, of course, its accuracy and precision. To be able to test SprintTimer under controlled but realistic circumstances a special test rig with millisecond accuracy was built (described at the end of this post). More than 150 “races” were run on different iPhones and iPads under different conditions and setups. The overall result was very satisfying.

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Adding an external display

The main reasons to connect the iPhone/iPad to an external monitor, TV, or projector are either to present the running time or to show the finish-view. When you connect an iPhone you normally get a mirror of the screen, so also with SprintTimer. In two situations, however, will the app send something different to the external screen: When viewing a photo finish you will get a much broader version of the finish-view that fills out the whole screen. And during the race will the external motion display the time in a large font. The latter means that you set up a display so the audience can get a live view of the running time.

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Creating start lists with spreadsheets

A spreadsheet is a convenient tool if you don’t have dedicated sports meet software to manage your start lists. There are several ways to transfer the list from the spreadsheet to the Results manager in SprintTimer. They are briefly described in the Guide, but there are a large number of options, so this post will give some more details and tips about how to set up an effective workflow. I will assume that you are using a spreadsheet on a Mac/PC and want to import it into SprintTimer. I will give some tips on how to work with Apple Numbers, Microsoft Excel, and Google Sheet. I will also discuss how to transfer the data via iCloud Drive, DropBox, Google Drive, and Microsoft OneDrive.

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Making a starting E-Gun

This is a much-improved version of an older post.
An electronic starting gun/pistol/device is a useful tool since it is entirely risk-free and lets you control how loud the sound should be. It can also be connected directly to SprintTimer, which makes it insensitive to external noise. But while an e-gun is not very expensive, it still costs around $200. So if you are on a budget, or like DIY projects, you can build one yourself at a tenth of the cost. That might sound hard, but there is no programming involved, and you only have to connect two wires. It will also be more flexible than commercial guns since you can decide what type of sound you want and how to trigger the start.

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With SprintTimer as the starter

The self-start mode is obviously useful when you want to time yourself, but it might have other purposes as well. For example, can it be used for a group of runners when there is no coach available, or when he wants to be at the finish line. As always is the communication between the start and the finish a challenge, and I will, therefore, go through some options.

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On clocks and synchronization

This post might be a bit technical, but can help you understand how a smartphone or computer measures time. 

Every smartphone and computer has a clock, so measuring time shouldn’t be a problem? Well, that is true if you want to know the time of the day within a second or so. But if you’re going to take milliseconds into account, it can become trickier. The clocks in smartphones are controlled by an oscillator, e.g. a crystal, in the same way as an electronic watch. Unfortunately, do the manufacturers prioritize cost and energy consumption over very high accuracy when picking oscillators (Apple is no better or worse than others in this respect).

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Adding a front line camera

For any timing tool the best accuracy is achieved by measuring the time from the side, and in line with the finish line. A big disadvantage though is that it can be difficult to identify the competitors. Hip numbers can be a solution, but is not always practical. But with SprintTimer you have another solution that maybe not is so obvious. If you have access to an extra iPhone or iPad you can use that as a frontline camera synchronised with the timing camera.

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Improving motion detection

Motion detection is an important feature in SprintTimer. In Video Finish it helps to reduce the number of frames that you have to shift through. In Live Finish it is the key factor for measuring time. So I thought that explaining how it works might help you apply it successfully. The first thing to realize is that it not really is motion detection, but rather change detection; the motion creates changes in the image that are detected.

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Sprint Testing

Sprint tests can be conducted in more ways than ordinary races. The different setups in SprintTimer therefore come in handy, for example, you have the option to choose from either convenient ”timing gates” or the more accurate Photo Finish.

Many tests are over a 10-40 m distance, which is favourable since it means that you might use Start Sender without an external network. It is usually possible to connect two iPhone/iPads directly to each other over 30 m (40 m with luck). Below I have described some alternative setups that hopefully can inspire you to find the best configuration for your test.
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The stand alone finish line camera

One of the strengths of SprintTimer is that is an ”all in one” solution with a camera, display and result generation in one small, neat smartphone package. But it is sometimes also a weakness, it can prevent you from placing the camera in an optimal place since you must access it after each race. Or you might not have time get the results after each race if they come too frequently. The recent updates of SprintTimer, however, has made it possible to place one iPhone/iPad as a remotely controlled finish line camera and handle everything from one or two other devices.

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Connecting an electronic starting gun to SprintTimer

The most accurate method to start the clock in SprintTimer is to use the sound from the starting gun, either directly in Photo Finish or via Start Sender. You need a microphone placed close to the starting gun to get a sound that is significantly louder than the surrounding noise (cheering crowds, wind etc). But with an electronic starting gun, an even better solution is to connect the starting gun directly to the headset jack on the iPhone/iPad.

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