CircleLock

A smart lock with no screen: ESP32-C5 firmware and an iOS app.

How it opens the door. The box sits on the door about two feet under the handle, and the servo winds a string onto its spool to pull the lever down. An animation modelled on the CAD below, not footage.

The phone signs an offline ECDSA P-256 challenge inside its Secure Enclave. The cloud can carry the command, but it never gets to decide that the door opens.

What's inside

Walk-up detection from an iBeacon arrival state machine.
Motor safety: watchdog-capped servo control, jam detection from learned travel, and a failsafe when the link drops.
Every module is split into a hardware half and a host-testable half. 411 tests pass with no board attached. Hardware bring-up is next.

Six screens of the CircleLock app, each a single circle over one word. Closed: an empty green ring. Opening: the ring half filled. Open: a solid green circle. Checking: a white ring. Not you: a dim ring with red lettering. Jammed: a ring half filled in dark red. — The app's one screen, in six of its twelve states. The circle shows the door and is the only control.

CAD view into the open enclosure: a servo with a flanged spool on its shaft beside a round opening in the wall, a blue relay on its board, and the mounts around them. — The enclosure in CAD, with the servo, its spool and the relay in place.