Timekeeper for doing time trials with my RC car model

This is a Spring Boot application accessible via standard web browser that sits on a Raspberry Pi and is connected to a photocell. When the model car passes the start line, the photocell is interrupted and the timekeeper displays lap times and total race time. See it in action on youtube.

Usage Instructions

1. Get a photocell with open collector transistor output, like this one.
2. Connect photocell power and ground as needed, and its output to pin 13.
3. Build fun-timekeeper.jar using maven or download the latest release.
4. Launch the timekeeper on your raspberry using java:

   java -jar -DlapsPerRace=3 fun-timekeeper-1.0.jar

5. Open http://address-of-your-pi:8080/ in the browser.
6. Click Start Race and put pedal to the metal.

To clean the records remove races.json and restart the app.