Turn a Desk Chair Into a Novel Input and Force Feedback Device

Haptic feedback is usually focused on your hands, whether in the form of a smartphone, VR controller, or computer joystick, but what about the desk chair in which you sit? If you've ever wondered about adding a new input and feedback method to this type of office furniture, the Aarnio project by researchers across several institutions does just that, adding resistance and sensing in three axis: rotation, rolling, and tilt.

To implement these new capabilities, Aarnio uses an Arduino Uno board linked to a computer via USB. For rolling, the chair is augmented with a bicycle-style disk brake, which clamps down as needed to modify the resistance to turning, and thus signal the user. Input here is sensed via an accelerometer, which also determines how far the chair is tilted back. Tilting force feedback is similarly modified with a DC motor, which cranks down on the spring holding the backrest in order to regulate the force holding a user upright. Finally, rolling force feedback is taken care of by five servo motors, which lock the casters in place or release as needed. An optical sensor from a computer mouse then detects movement as an input.

In trials, tilt axis recognition was around 87%, while rotation and rolling were both recognized at around a 93% rate. Such a system could be used for gaming, as an input method for those with certain disabilities, or as feedback in an office environment, where checking the time and/or your phone over and over is generally considered rude. Aarnio has even been tested in a chair racing application as seen in the video below, with a variable resistance depending on “track” conditions.

See the full research paper on this experiment here.