A project made in the course Shape-Changing Interface, which I was later a teaching assistant in, that resulted in a publication and showcase at the TEI’14 Conference in Munich. Through a prototype, we explore how we could raise awareness of the invisible wireless communication that surrounds us, in relation to spatial shape-changing interfaces. So far, this area of research has been largely unexplored. In order to explore this, we have built an installation that reacts to radio waves emitted by personal devices like smartphones and tablets, causing unanticipated movements.
KINETIC WAVE Category Tangible Interfaces Date Spring, 2014 Homepage KINETICWAVE.SPACE Publication Kinetic wave: raising awareness of...
Kinetic wave: raising awareness of the electromagnetic spectrum
Søren Pedersen, Michael Ha and Anders Høedholt
The installation consisted of twelve, frosted acrylic rings (with electroluminescent wire on the edges) that was suspended from the ceiling and controlled by their own separate stepper motor. Through sensor readings, the rings would create a corresponding wave and give the feeling of a floating blue wave. More details and technical description can be found on KINETICWAVE.IO
Design Process & Technical Implementation
Controlling the Rings
Sensing the nearby Wireless Signals
Kinetic Wave reacts to wireless communication around it, so we needed a way to detect this in an anonymous way. An RF power detector proved to be the solution, since it is a very generalized way of detecting the amount of radio communication. We got the LT5534 chip from LINEAR Technology, and they were really kind to send us a couple of free samples. Our only challenge was to solder the chip onto a breakout board, since it is tiny.
The chip is an RF power detector that works in the 50MHz to 3GHz frequency range. Our primary aim was to measure Wi-Fi and 3G / 4G networks – around 1.8 GHz or 2.6 GHz for 4G in Denmark, and typically 2.4 GHz for most 802.11n networks. We can roughly adjust which frequency bands the detector should be most sensitive to by the length of the antenna. We made a simple 12 cm wire antenna, which gives a good input at those frequencies.
Creating the Wave
Every ring is connected to two wires which are rolled up and down by custom-made pully-wheels driven by stepper motors. Each motor is controlled by a separate AutoDriver board, which is based on the L6470 Stepper Driver. The board keeps track of the rings position and the move-instructions. In other words, every ring has its own pully system, controllerboard and stepper motor. The motors we use are bought from Sparkfun, and the Sparkfun AutoDriver board makes controlling them precisely with Arduino a breeze.
Let there be light!
The major components of the installation include the base station at the ceiling and the twelve rings suspended from it. We designed the ring stencil in Adobe Illustrator, and afterwards had it lasercut in diffused acrylic at Aarhus School of Architecture. The base station is made by hand and out of aluminum and is designed to hold the stepper motors and electronics, whilst still being lightweight.