Guide · Technology

Privacy by Design: How a Sun-Tracking Mirror Runs Locally

A device that reflects sunlight has a hard job beyond aiming: it must never steer the redirected sunlight into anyone's eyes. The obvious route there runs through image recognition - and therefore through an image sensor in your own garden. The ohoya heliostat takes a different route: it solves the job geometrically and computes locally.

The problem: safety usually means a camera

To keep a sunbeam off faces, a system usually needs to know where people are - typically solved with a camera streaming video to a cloud or at least to a chip inside the device for analysis. For a product that lives on your terrace and looks toward your home, that's a hard compromise to justify.

The answer: geometry instead of image recognition

The ohoya Heliostat solves this differently: you set exclusion zones and the firmware never moves into them; separately, the mirror is slightly convex, so no focal point exists by design. You set exclusion zones (e.g. over a neighbor's window) once, using augmented reality on your own smartphone - the device itself needs no camera for this. Firmware remembers these zones permanently and blocks any movement into them, even after a reset or a move.

Four layers that keep it private

• Image sensor: none. There is nothing on the heliostat that could record an image.
• Glare protection: three measures, not one. The slightly convex mirror shape and fixed no-glare zones in the firmware work together with the placement guidance you follow when you set it up - two of them sit in the device, the third one is yours.
• Exclusion zones, set once. AR setup runs through your phone's camera, not the device's. Zones are world-anchored and stay valid even after a reset.
• An additional thermal sensor. A discreet, imageless sensor (AMG8833) on the device front.

Why local control does more than protect your privacy

Because the sun's position is computed locally from clock, date, GPS and compass, the heliostat doesn't need the internet to do its core job. That means no account to create, no server outage that can break it, and no ongoing data outflow. Local control is also faster and keeps working if your connection drops. (New to the concept? Start with what a heliostat is.)

Note: the ohoya Heliostat is in pre-series development. Stated safety characteristics are development goals and are verified per EN 62471 before public marketing.