Kawaiicon, New Zealand's premier hacker conference, took a bold step to ensure the health and safety of its attendees by implementing a real-time, room-by-room carbon dioxide monitoring system. This innovative approach was a response to the challenges posed by the ongoing measles outbreak, COVID-19, influenza, and RSV, which have made large gatherings risky. The conference organizers installed DIY CO2 monitors throughout the Michael Fowler Centre venue, providing attendees with a unique opportunity to check air quality before even arriving. This system, developed in collaboration with researchers from the University of Otago's public health department, used RGB Matrix Portal Room CO2 Monitors, offering live readings, daily highs and lows, and historical data. The monitors were strategically placed in various areas, including the Main Auditorium, Renouf session space, daycare, Kuracon (kids' hacker conference) areas, Quiet Room, Registration Desk, and Green Room, ensuring comprehensive coverage. The organizers also created a user-friendly online dashboard, accessible via QR codes on custom-made posters, allowing attendees to quickly check CO2 levels and decide on their safety measures. This DIY solution, with resources, parts lists, and assembly guides available, empowers any conference to prioritize air quality and attendee well-being, even during challenging times.