02 ‐ Overall Concepts

As stated, this project was designed for a very specific event - 6th grade robot car races. But it can be easily adapted as long as you understand the basic concepts of how the system works.

For this implementation, a single ESP32 will control the entire system. A time-of-flight sensor is used both at the start and finish line. As soon as a racer's car touches or crosses the finish line, a timer consisting of a MAX7219 dot-matrix display (with whole or optional tenth of a second resolution) will start and then stop again as soon as the car touches or crosses the finish line.

Optional LED strip lighting down the course will change colors to reflect the current stage of a race:

• Ready: System is 'armed' and ready to start timing.
• Active: An active race is occurring and the timer is running.
• Completed: The car has reached the finish line successfully and the timer has stopped.
• Timed-Out: The racer took longer than the allocated time for a race and time has expired.

The LED colors are configurable via the settings page after installation and initialization of the firmware.

The system also has an option for manual timing mode in which case the sensors are simply ignored and time is manually started and stopped via a button on the timer display. Manual timing mode can be selected at any time via a toggle switch on the timer. LEDs, if used, will still reflect the current race mode even when manual timing is used.