Six-Lane Quiz Buzzer
First-press lockout, commissioned by the department and used live.
If the code stops at the first pressed lane it finds, lane one always wins a close call. With a live audience, people would have noticed.
Problem
Six teams, one buzzer, an audience watching, and no room for an argument about who pressed first.
System
Six buttons, six lane LEDs and a buzzer on an Arduino. The first press locks out the other five; the host then awards the point or resets.
My part
Whole build, commissioned and paid for by the ECE department. Structure and host-control flow follow an open-source quiz buzzer by Alastair Aitchison (Playful Technology); the tone generation is my own.
Result
Ran a full quiz for five teams at a live college event. The scan reads all six lanes before deciding, and a tie inside a single scan is genuinely unresolvable, since the loop runs in tens of microseconds while human reaction differs by tens of milliseconds.