Case study · TU Eindhoven

Disconnected Controller

The smart home made everything controllable and put every control in the same place: your phone. This project keeps the remote control and drops the smartphone: a twistable, doorknob-shaped object tracked by a camera, so the interface stays physical, and you can truly detach while still remaining in control.

Role: Individual project: concept, build and evaluation
Context: MSc Industrial Design, TU Eindhoven
Timeline: November 2023 to February 2024
Scope: Concept · Computer vision · Working prototype · Research paper

A hand lifting the doorknob-shaped controller in front of a white wall panel with a thermostat dial and LCD, a camera above and a glowing lamp beside it. — Lifting the controller in front of the test wall: thermostat, lamp, and the camera watching from above.

01Question

Every convenience of the smart home currently routes through a screen that also carries your email, your news and everyone else’s opinions. Checking the thermostat costs a slice of your attention. The project asked whether you could keep remote control of the home while disconnecting from the digital world entirely: no smartphone, no app, no account.

The answer had to be an object: something that lives in the room the way a remote used to, that anyone present can pick up and use: control as furniture, not as a session on somebody’s phone.

Convenience shouldn’t cost you your attention.

02Form

The form borrows the oldest control mental model in the house: the doorknob. You already know what to do with it: lift it, point it, twist. A flat base means it rests on any surface without triggering anything; picking it up is the act that arms it.

The controller is 3D-printed, with the ArUco marker set into its flat underside, the one concession the object makes to the system that watches it. A small indentation in the spherical top marks the midpoint of the range, so the hand can feel how far the knob is turned instead of checking a screen for it.

A sheet of pencil form sketches for the controller: cylinders, faceted solids, doorknob and chess-piece shapes, each annotated with where the CV marker would sit. — Form exploration: Where does the marker go, and can the camera still see it?

Close-up of the white 3D-printed controller: a domed top with a vertical indentation running down it, seated on a wide flat circular base. — The printed knob. The groove down the dome is the midpoint, feelable without having to look.

03Vision

There are no electronics inside the controller at all. A 1080p camera watches the room; a Python script finds the marker and serves its position and rotation, a Processing sketch relays that over a COM port, and an Arduino turns it into device values. Rotation around the vertical axis becomes brightness or degrees; horizontal position picks which of the two devices is listening.

An empty object is what keeps it dependable: no battery to charge, no pairing to fail, nothing to update. The intelligence sits in the room, and the thing in your hand stays a thing.

A desk-height test wall: a lamp glowing blue-violet on a white plinth, a hand holding the white controller to the right, an office visible behind. — One lamp, one thermostat, one camera between them to prove the concept.

The thermostat side of the wall: a blue LCD reading Desired Temp 22.0 above a white knurled dial with a thermometer icon, the controller held alongside. — The thermostat answering. The knob was moved via a stepper motor and the change illustrated on the LCD.

Close view of a hand tilting the white controller toward the glowing lamp, the camera mounted above in frame. — Twisting the knob while pointing at the lamp turned it on and adjusted the brightness.

04Findings

The prototype works: brightness and temperature adjust smoothly, the doorknob needs no explaining, and the whole loop runs without a phone or an account. What it doesn’t have is proof. The project ran on a short timeframe and no user testing was conducted, so that reading is mine, not a study’s.

The real outcome of the report? A camera watching a living room is a real privacy question, not a footnote. And a twist maps cleanly onto brightness and temperature but not onto devices that ask for more than one number.

This project was only ever meant as an exploration, a first step to build on.

The prototype electronics: an LCD module mounted on a wall, a stepper motor with a cardboard pointer, and an Arduino on a breadboard, wired together on a plywood base. — Behind the wall: the LCD, the stepper standing in for a thermostat dial, and the Arduino translating marker angles into values.

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