Why do my hands have to be underwater for 2.5 seconds at the start and for a lap change?

Our software analyses your swim data to intelligently determine your actual swim time, so you can leave the stopwatch at home. But there are a few things to be aware of:

1. After you have started the recording (LEDs are flashing green), the software waits for you to push off before the timer begins. To trigger the push-off, both hands need to be underwater for at least 2.5 seconds.
2. The software also looks for 2.5 seconds of continuous submersion to detect a lap change ie. gliding into and/or out of the wall.
3. When you finish your swim, or are taking a rest between laps, simply lift one or both hands out of the water for 2.5 seconds or more to indicate the end of the swim.