Are you one of those people who never closes a door behind you? Then this project may be interesting for you or your entourage. The creator of this project lives in a house where doors stay mostly ajar, i.e. almost closed but never completely. A closed door means that someone is behind it and closed it on purpose, usually to secure some privacy. However, it can be hard to see from a distance if a door is closed or slightly ajar and so this Poster started thinking of an elegant system capable of signaling the state of the door. The Smart Door was born.

The system is simple: a magnet and a reed relay create a classic door open/closed sensor. A microcontroller reads the sensor and makes an LED blink if the door is closed. Of course a microcontroller is not really necessary for this, but it has the advantage that the circuits can remain very simple and small. The latter property is especially important because of the project’s Elegancy requirement: it must be small enough to be hidden in a standard door without damaging it.

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