One month into open alpha, Circadia has moved from a tool I built for my own impossible sleep into an app with enough real N24 data to make the research side feel less theoretical. The Community tab is live, Jon replaced the particle filter forecast with a tag-aware Kalman-IMM model, and the app now has enough users to expose the administrative layer under health software: platform rules, security audits, server costs, and the boring financial reality of keeping something useful alive.
A plain-language guide to Non-24-Hour Sleep-Wake Disorder (N24): what it is, what "free-running" means, why sighted people get it too, how it's diagnosed and managed, and why several of its stranger features — marathon wake periods, sleep debt that won't clear, a sleep window that slams shut — are completely normal for the disorder.
Two τ Changes Today, and the Bug I Caught On My Own Data
Why your τ tile might look a little different from this morning — and why the change is mostly the math finally admitting it can't fit a 30-hour cycle onto a 24-hour clock face.
Why Circadia lets you change the math behind your sleep — and why my own settings look nothing like the defaults. Featuring a very bad Airbnb, a fourteen-hour lurch, and the embarrassing number of hours I do not spend asleep.