About this app

Sundials are one of humanity's oldest instruments — and building one that actually keeps time is easier than you think. AR Sundial Builder guides you, step by step, to lay out a genuine working sundial in the real world, using your phone's camera to place every line exactly where it belongs. No guesswork, no complicated math on paper. Point your phone, follow the guide in augmented reality, and watch the dial take shape in minutes. WHAT YOU CAN BUILD • Horizontal sundials — the classic garden dial that sits flat, facing the sky. • Vertical (wall) sundials — mounted on a wall, including walls that face off to one side rather than straight south. More dial types are on the way — you'll see them appear in the app as they arrive. HOW IT WORKS 1. Place the center of your dial in AR and set its size. 2. Align it to true north with an on-screen compass guide, then lock it in. 3. The app draws the correct hour lines and gnomon (the shadow-casting edge) for your exact location. Every hour line is positioned from your latitude and the real geometry of the sun — the same principles a traditional dial-maker uses. SEE THE SUN, READ THE TIME A live sun-and-shadow guide shows where the sun is and where the shadow should fall right now, so you can check your dial against the real sky — and read the time straight off the dial as the shadow moves. LEARN AS YOU GO Tap through built-in explanations of how sundials work — the gnomon and style, why your latitude matters, how a wall's direction changes the design, and why sundial time differs from clock time. A hands-on way to explore astronomy, geometry, and history. Great for students, teachers, and the endlessly curious. SAVE YOUR DIALS Name and save the dials you design, and reopen them whenever you like. ACCURATE — AND HONEST ABOUT IT The geometry follows established sundial-making principles. That said, a phone is not a surveyor's instrument: results depend on your device's sensors, compass calibration, and GPS. Treat your dial as a wonderful, working approximation — not a tool for navigation or safety-critical use. PRIVATE BY DESIGN • No account, no sign-in. • No internet connection required. • Everything is processed and stored on your device — nothing is transmitted to us or anyone else. Your location and camera are used only on your phone, to build your dial. Grab your phone, pick a spot, and build a sundial that really tells time.