ARCord: Visually Augmented Interactive Cords for Mobile Interaction
Research on wearable controllers has shown that body-worn cords have many interesting physical affordances that make them powerful as a novel input device to control mobile applications in an unobtrusive manner. With this work, we want to extend the interaction and application repertoire of body-worn cords by contributing the concept of visually augmented interactive cords using state-of-the-art augmented reality (AR) glasses. This novel combination of simultaneous input and output on a cord has the potential to create rich AR user interfaces that seamlessly support direct interaction and reduce cognitive burden by providing visual and tactile feedback. As a main contribution, we present a set of cord-based interaction techniques for browsing menus, selecting items, adjusting continuous values & ranges and solving advanced tasks in AR. In addition, we present our current implementation including different touch-enabled cords, its data transmission and AR visualization.
Membrane Potentiometer Cord
Our first cord sensor is made of a commercial SoftPot potentiometer that is sewn in a fabric cord (see A) and captures squeeze positions. The sensor is bendable and acts as a linear sensing device and can be used with any standard analog-to-digital converter (GND, 3.3V, A1) (see B).
The video shows how a user slides about the cord, while in the background raw sensor values are displayed.
Capacitive Touch Cord
Our second sensor integrates twelve capacitive pads and is made of multi-conductor zebra fabric and conductive yarn allowing multi-touch recognition without any instrumentation (see A).
To sense all conductive pads we used a NXP MPR121 breakout board from Adafruit via I2C (see B).
Moveable Ring Slider
For our moveable ring slider sensor, we fabricated a series of prototypes in a iterative design process. Or first sensor (A) consists of a resistive cord and a dedicated wiper that measures the position. Our next iteration (B) is made of a double-sided cord with a resistive material and copper tape. A moveable ball bridges both layers and thereby creates a unique resistance. The second sensor has the disadvantage that the copper was cumbersome and tends to broke. Therefore, we developed a further version (C) with a highly conductive and very flexible cord.
The video illustrates how a user moves the slider ring, while in the background the corresponding raw sensor values are shown.
Tactile Confirmation Button
In addition, we add an additional tactile push-button at the end of the cord enabling explicit confirmations. The casing is 3D-printed with black ABS.
Visual Feedback for Cord Controls
For our current implementation, we use the Microsoft HoloLens as state-of-the-art AR glasses and place all visual control overlays in front of the user at the body-worn cord.
The video shows how the control visuals are placed at the cord. The video sequence was recorded with a second HoloLens. That is the reason why all controls are aligned to the video perspective.