ASL puts grammar on the face: raised brows turn a sentence into a yes/no question, furrowed brows mark a wh-question. Signpost ships with one sensitivity for everyone — teach it yours and those signals will register the way you actually sign them.
Everything runs in this tab. Signpost stores four numbers, never video.
Rest, raise, furrow — about two and a half seconds each. Signpost measures how far your brows travel and moves the trigger point to match, so you never have to over-act a question.
Until you calibrate, lessons use 22% raise and 30% furrow as the trigger points.