E14 Echoic Steps
Peter Torpey
March 2009
This proposal outlines a non-destructive installation for E14's stairways. Primarily intended for the four promenade stairways in the lower and upper atria, the concept can readily be extended to the other stairwells and spiral lab staircases in the building.
Concept
In this installation, the upper face of each step will glow in response to being stepped on. The width of the step is divided into several regions, nominally six, that respond to pressure. When a region is stepped upon, it glows. Once the passerby removes his or her foot from the region, the glow fades. Each step maintains a history or accumulation of the number of times during a certain period, perhaps a 24-hour day, on which it has been stepped. This count affects how brightly the region glows when not being stepped on.
The effect of this is in many ways familiar to early interactive art pieces, in that it displays a trail of the user. These trails accumulate over time, showing paths frequently traveled and those areas infrequently tread upon. It serves as a visualization of the traffic among floors 1 through 5 on these stairways.
Objectives
The objective of this installation is to encourage not only vertical movement through E14, but vertical movement by way of stairs. Use of the stairs is often considered more healthful and, in E14, it allows for residents and guests to experience the central spaces of the building, provides views into many of the labs through the glass walls, and increases the potential of spontaneous encounters with others in the building.
The installation is interactive, but in a passive sense. A person need not do anything out of the ordinary to interact with it. It also visualizes cumulative traffic flow on the stairways in an anonymous way.
The presence of the installation would make taking the stairs to other floors a unique and enhanced experience. The history of traveled paths may prompt individuals to follow a well-worn path or to walk up a portion of the stairway not frequently traversed. Clever users may learn to walk up and down stairways in particular ways repeatedly to “paint” step regions as pixels, ultimately revealing a low-resolution image or message that will be later washed away by others taking the stairs, as would be writing on a sandy shore. The hall on the E15 side of the upper atrium on the fifth floor would provide a vantage of all four stairways, thus promoting travel up through all five floors of the building.
Construction
The installation is contructed by outfitting each step with a single assembly. Two sizes of assembly would be required to fit the 12″ and 16″ deep steps of the four main staircases. There are 48 steps of each size in the building. The assembly would fit on top of the existing step, with cut-outs for railing posts where appropriate, and require minimal adhesion or other attachment to remain in place.
Each assembly consists of three layers of matieral. The top surface is 0.25″ Acrylite EndLighten or transparent acrylic. EndLighten material is designed specifically to accept illumination from its edges and internally transmit the light evenly from its clear surfaces. If standard acrylic is used, one side of the acrylic should be sandblasted or scored to provide a similar effect when illuminated from the edges. The 0.25″ should be sufficient to withstand the stresses of footfall impacts. Beneath the transparent material is a thin layer of opaque white material that will provide a backing for the illuminated surface. The bottom layer is a thin cushion material to absorb footfalls and to possibly allow the assembly to be adhered to the original step. In this bottom layer are embedded capacitive or piezo sensors at the center of each region.
The three layers are held together at the trailing edge by a C extrusion and at the leading edge by a similar extrusion as part of a nosing that overhangs the riser. The nosing may be textured to provide traction. The channels of these extrusions house LED strips segmented into pairs of circuits for each region of the step. Each circuit is a pair of LED strips across from each other along the leading and trailing edges. The wiring for the LEDs and sensors is also run in these channels.
A small extrusion or box along the depth of the step rests against the inside stringer. The wiring from the channels leads to a microcontroller housed here. The microcontroller maintains the state and counts of each region on the step, processes pressure sensor input, and controls the LED output. A multiplexer and LED controllers, such as a BuckPuck, may be required to provide constant current to LED strips given a PWM signal from the microcontroller. A channel descends the riser into the controller housing for the step below, allowing for a common power bus and optional serial communication for each stairwell.
Variations
As described, each step assembly is a functionally independent unit requireing only power. With this configuration alone, a number of variations on the above concept are possible.
With RGB LEDs, the color of light output may be varied. For example, the color may be chosen to match the characteristic color of the stringers of each staircase. Color may also be used to provide additional information about the trails displayed. Relying only on time, each trail may be given a color from a cycle. (More preciseily, all trails created within a window of time would be given a unique color.) The color of the trails may be used to distinguish them or vary slowly over time, providing a chronology of traversal over the course of a period of time. A single step may be fully illuminated (or inversely illuminated producing negative trails) at a given time providing a function of a clock. Since each stairway has a total of 24 steps (not including floors or landings), one step could be mapped to each hour of the day. This hour step would move linearly, providing a time of day to viewers, and serve as a key for the color used in all trails for that hour.
If all of the steps are powered on instantaneously, it may be possible to achieve adequate temporal synchronization without the need for step assemblies to communicate with each other. However, a serial communication connecting all steps in a stairway can open the door for many more applications, including loading imagery onto the stariwell-wide raster to brand particular events or even provide directions through the building to an event.