Sprint Start Countdown & Reaction Timer

This app will audibly play the words "on your marks" and "set," followed by an (optional) random delay, and then a starter pistol shot. It can also measure how quickly you react to the starter pistol.

NEW: "Coach Mode" now allows coaches and race officials to manually play each sound in the countdown, or to start an automatic countdown from either "On Your Marks" or "Set," and to play a second gunshot if they witness a false start.

KEY FEATURES:
- Simulates an "on your marks," "get set" and "go" (or gunshot) countdown with audible and visual cues.
- Gives you the option of randomizing the delay time between "set" and "go" in order to simulate variation between race officials. You can also choose a fixed delay time.
- Tracks how quickly you leave the starting block with an included reaction timer.

IN-APP PURCHASES:
- The "reaction timer" and "random delay" features can be used for free 50 times. Afterwards, the user will be asked to purchase the full version for $2.99 to continue using those two features.
- All the other features in the app are free forever.

EXTRA FEATURES FOR SERIOUS SPRINTERS:
- Turn on "crowd noise" in the background, to learn not to get confused by coughs or murmurs.
- Choose whether the app will accept starts that are faster than 100ms, or reject them in accordance with IAAF rules.
- Review your history of start times and track your progress on the "analytics" page.
- You can disable the "on your marks" part of the countdown and have the app skip straight to "set" in order to save time during long practices.
- Both visual and audible cues are provided during the countdown, to enable use by the hearing impaired. You can also choose to disable the audio and rely solely on the visual cues.

AND JUST FOR FUN:
- Choose from multiple different recordings and sound effects for the "gunshot" sound and the "on your marks" announcement - including a few fun ones :-D

The reaction timer works through your phone's touchscreen. To use it, get in the sprint start position and place the phone under your thumb. Hold down the "go" button to start the countdown. When you rise from the starting block, you will naturally lift your thumb off of the screen. The app will capture the length of time between the gunshot and your finger-lift, and report this as your reaction time.

This is a sequel to my old "Sprint Start Trainer" app from ~6 years ago. I've re-written it from scratch to add a bunch of new features and improve stability. Hope you find it helpful!