A Browser Extension That Knows When You Actually Left Your Desk
Standing-desk reminders are a commodity, but most are oblivious to whether you actually moved. Tying reminders to OS idle state and lock-screen events — and handling the resulting state-machine complexity — turns a nag into a credible health log. For anyone stuck in Chrome all day, it's a zero-friction install that doesn't touch a server.
Most sedentary reminders are just countdown timers that pop up on schedule, regardless of whether you already stood up. This extension fuses Chrome's idle API and lock-screen signals to detect genuine breaks: a bathroom trip, a water refill, or a meeting all reset the clock automatically. It also handles edge cases that break naive timers — overnight shutdowns, Service Worker suspensions, and deadline crunches — through a 1,100-line finite state machine running entirely offline under Manifest V3.
A weighted health score (60 points for rest frequency, 40-point linear penalty for the longest single sit) gives immediate feedback when you overstay by even one minute. A "Busy Now" mode suppresses popups but keeps accumulating overtime in a red badge, so the warning stays visible without interrupting flow. Daily snapshots, a 7-day trend chart, and full JSON export/import make the data portable across machines.
Built with zero dependencies, zero build steps, and zero servers, the extension stores everything in chrome.storage.local. The developer started it after a hospital visit diagnosed cervical spine straightening and lumbar strain — the tool is now in daily use and planned for open-source release.
Most "stand up" reminders fail not because people ignore them, but because the timer has no model of whether the user already stood up — idle detection closes that gap.
A linear penalty in the health score (rather than a stepped or threshold-based one) makes the cost of over-sitting immediately visible, which is a deliberate design choice favoring continuous feedback over delayed punishment.
Building this as a browser extension rather than a standalone app sidesteps corporate IT approval friction and smartwatch dependency — the lowest-friction distribution channel for desk workers is the browser they never close.
The project's origin story (a hospital diagnosis) explains why the feature set prioritizes non-intrusiveness: the reminder is a dialogue with options to defer, dismiss, or mark a false alarm, not a binary alarm clock.