Arduino Lap Timer System

The goal is to turn an Arduino into reliable timing equipment for track-day cars. I already know the core requirement: precise lap timing triggered by track-side sensors, with each lap time shown live on an attached LCD screen so drivers can see their results as they pass the pit wall.

What I need coded is:
• Accurate capture of a start/finish trigger (IR beam, magnetic reed, or similar—happy to follow your recommendation)
• Millisecond-level lap calculation that stores the current lap, previous lap, and best lap in memory
• Real-time display of those three values on a 16×2 (or comparable) LCD; the screen should auto-update as each new lap registers
• Simple push-button reset to clear the session without rebooting the board

Deliverables:
1. Clean, well-commented Arduino sketch (.ino) ready to upload
2. Minimal wiring diagram showing the Arduino, chosen sensor, LCD, and reset button
3. Short parts list so I can source identical components locally
4. Quick-start guide that walks me through calibration and testing at the track

I will test the build by running ten consecutive laps; the system must not miss or double-count any trigger and must display each time within one second of passing the line to be accepted.