SprintTimer Guide

Start Sender (Pro)

Start Sender records the start time and activates Photo/Video/Motion Finish on another device. It can also be used as a remote control to start and stop the video recording. Start Sender has two modes:

The devices are in direct contact with each other over WiFi and can synchronise the clocks directly. For short distances, no extra hardware is needed, but for distances over 30 m an external WiFi network is required (but not internet access).

The devices communicate with online time servers and iCloud. An Internet connection is therefore required, either over a cellular/mobile networks, or via a WiFi connected to Internet.

Synchronization and set up
Before using the Start Sender, the devices must be synchronized to establish the difference between the internal clocks and to set up the communication. In Cloud mode this is done automatically in the background. In Direct mode you must start the sync manually.

Direct Mode

  1. Turn on WiFi on both devices (plus Bluetooth if you are running without an external network)
  2. Open StartSender from the main menu on one device.
  3. In Photo/Video/Motion Finish on the other device, go to Start Set Up and choose the mode Start Mode: Start Sender. Tap the Synchronize button when the text says "Start sender found". Synchronization usually takes 10-15 s.
  4. When it says "Ready to run" you can close the Set Up.

Start Sender will continuously update the clocks, so there is no need for resyncing, unless the communication is lost.
A video of the set up ->

Cloud Mode

  1. Check that you have Internet access
  2. Check that you are logged in to iCloud (same account on all devices)
  3. If you are using the mobile network go to Cellular (green radio mast icon) in the settings app and turn on Mobile data. Scroll down and check that SprintTimer is allowed to use mobile data.
  4. Set the Start Sender Mode to Cloud on both devices.

A start in Start Sender will open the camera in the finish line device, and you can then start the recording the usual way. If you want the finish device to be completely autonomous go to Set Finish on the finish device and set Start recording to Time or Motion and turn on Auto finish. Alternatively, you can turn on Remote recording in the finish set up on the Start Sender device. Then you can start and stop the recording from start sender.

The start in Start Sender works similar to when you use only one device (see the Start guide). The differences are that there is no Hand+Mic, but instead, there is a Start on motion, which uses the camera to detect motion.

If you use Self start, Start Sender will also measure the reaction time. This is described more in detail in this blog post.

In Direct mode there is some feedback between the devices. The start and activate buttons are disabled when the receiver is not ready. You can also activate the sound start from the finish. If the connection is broken both sides are notified.

In Cloud mode each side communicates with a server and you will get feedback if that connection is OK, but not necessarily information about whether the other side is active. Sending a start is, therefore, a bit like sending an email. There will also be a few seconds delay before the finish gets the start time.

Back up start
On the finish side there is a small "Hand Start" button. It will start the Photo/Video finish as if it was a single device with manual start. However, if it gets a start time from Start Sender after the button is pressed, but before the recording is started, that time will be used instead. So if you press that button at the start you will be sure to always have a time, even if the network is unstable. If the "Hand" time is used, the running clock in the camera view is shown in grey.

Apple Watch
The Apple Watch can be used similar to Start Sender. See the start guide for more details.

This page is also available at sprinttimer.se/support