Exhibition / Gainer Kaidan

IAMAS PDP (Programmable Device Project)
The Gainer Kaidan team (for the original version)
HIRUTA Sunao + HARADA Katsuhiko + SATAKE Hiroyuki + KASHIWAGI Emiko + AKAMATSU Masayuki + KOBAYASHI Shigeru

The Gainer Kaidan workshop team (for the extended version)
KOBAYASHI Shigeru + HARADA Katsuhiko + KAGECHIKA Masamichi + KASHIMADA Tomoya + MIZUTANI Kentaro + SUGIHARA Yoshihiro + 24 participants of the workshop

  • Venue: NTT InterCommunication Center [ICC]
  • Exhibition period: 2007.4.19 - 2008.3.9
  • Link: Open Space 2007
  • Support: Sunhayato Corp., IAMAS (Institute of Advanced Media Arts and Sciences + International Academy of Media Arts and Sciences)
  • Special Thanks to: IGARASHI Tomoko, IDE Haruka, ENDO Takanori, KOJIMA Ichiro, SAKAMOTO Mariko, TABEI Katsuhiko, SAWANO Chika, TAKAWO Shunsuke, MASUDA Ichitaro and YAMAMOTO Nobuyuki (alphabetical order)

Photo: Kenichi Hagihara

The brief overview

"Gainer Kaidan" was exhibited at NTT InterCommunication Center [ICC] (Tokyo, Japan) as part of the long term exhibition throughtout 2007, "ICC 2007 Open Space" (from April 19, 2007 to March 9, 2008). It was a media installation work produced by add-ons to the existing staircase, which linked the 4th to the 5th floorww. This work consists of the content part and the platform part, and the platform part has been published under the Creative Commons license (Attribution-Share Alike 2.1 Japan). More than 69,000 people have experienced during the exhibition period.


Staircases are usually less concerned location when we walk up and down, but unknowingly guided to walk according to the steps. Gainer Kaidan makes audiences conscious of their own body movements and the normally-uncousious relations between others who accidentaly present on the stairs. Since recent information technology devices like the PCs and mobile phones are high-density and complexed, these devices became into complete black boxes for users. In addition, the disproportionate emphasis on visual and manipulation by fingers has resulted in loss of body sensation about the interaction between a human and a computer. On the other hand, the experiences of Gainer Kaidan are all physical: The input is go up and down the stairs and the output is physically generated sounds by actuators. As a result, audiences can feel the function of the electorinic circuits and the operation of the invisible software. This work utilized the features of the Gainer toolkit such as users can develop and flexibly change the electric circuit through trial and error, and easily modify the circuit on the fly. The platform was constructed on the exsisting staris by adding sensors, actuators, wires and so on, and the platform ieself is an artwork. Therefore, these equipments (i.e. a PC, sensors, actuators and wires) which are usually hidden away were designed to be shown to audiences. This allows audiences can feel the structure and size of the system as cutaneous sensations. As well as software and hardware for input and output can be changed later, and the interaction varies from simple interactions to complex and dynamic ones. In addition, the platform has been published under a Creative Commons license, so aggressive secondary uses of the platform is possible.


In this works add-on to the staircase in ICC from 4th floor to 5th galleries floor. The staircase have 24-steps. We put 24 pairs of a laser emitting module and an optical sensors for each step to detect people go up and down the stairs, and 24 actuators (AC solenoid units) to make sounds like sounds of footsteps. In order to show the entire electronic circuits and make it possible to change freely later, we wired all electronic circuit by the 220 breadboards and over 11,000 jump wires which is normally used for prototyping of electric circuit without soldering. A breadboard has tabs on four sides to connect and expand the space horizontally or virtically. By using this feature, we linked two pairs of 110 bereadboards for the input and output side, then we attatched in parallel to the banisters. As far as we know, this is first time using so many breadboards at once. At first, all information of sensors that are installed on the bottom side breadboards are caputured by I/O modules for the input side and processed by the PC to detect status of each steps. 24 sensors (photocell) are located to be targeted by 24 laser emitting modules. If an audience interrupt a laser beam, the action is detected as a change of voltage of the corresponding sensor. We also installed 24 actuators (AC solenoid units), and each actuators is designed to hit a woddern face located on each steps by a rubber hammer to make sounds like footsteps. Activities of the whole system are shown in the screen of the PC that is located just before the staircase, so audiences outside the staircase can enjoy from a different standpoint.

Contents (original version)

The contents of the original version consist of three categories. The first category is a basic interaction, "delay": When a visitor steps on a step, the actuator on the same step hits the step and after a specific period, the actuator hits the same step again. This is a kind of delay effect in musical context, so an audience hears one's own step up or down actions. Thought this is a simple interaction, an audience can feel the physical feedback and reflect one's habit of walking at a staircase, the experience becomes interesting. The delayed sound is disabled when a visitor goes up or down quickly to make the interaction clear. The second category is a time signal. The actuators tap at each o'clock for the number of hours, audiences can know rough time in the museum. The third category is hidden commands, and several commands were implemented. The popular one is "wave": When an audience stops at a step for the specific period, the actuators tap in succession and back to the step. Since the sound is not played by speakers but generated physically (by tapping real steps), a visitor can feel as three-dimensional sound and enjoy the uniqueness, so it's worth experience over and over again.

Contents (expanded version)

On November 10th 2007, about seven months after the first version was published, we held a workshop as a part of a symposium regarding physical computing. The workshop was titled "Let's expand the Gainer Kaidan," and participants expanded the Gainer Kaidan. 24 participants were selected from among applicants, and they assembled expansion units during the workshop, and added the units to the Gainer Kaidan in the end. The expanded version was kept on exhibition until March 2008. The expansion units were assembled on the same type breadboards that were used for the original version. Since no soldering was needed to assemble an electrical circuit, the participants could easily assemble them guided by the instructions. The expansion units are designed as output units and actuators were LEDs. A unit has four LEDs and a micro-controller, an external trigger starts a sequence of LEDs: Two LEDs flash when they receive a trigger, then the other two LEDs flash after a specific period. Since an LED is a point light source, small blocks made of soap were used as diffusers. The soap used was a regular item. We carefully selected on among various types through experimental trials. The 24 participants assembled a unit for each, and installed a unit for a step on the fly without stopping the system. Since it's designed to modify the combination of colors of LEDs and delay time, an assembled unit is unique. Though the software itself was the same as the original version, audience can enjoy not only aurally but also visually with this expansion. As far as we know, there are next to no examples even in museums such as ICC where members of the public can modify a media installation piece and it is kept on exhibition as is. We realized a key concept of the original version: "dynamically expandable."

Contents (in the near future)

The platform of the Gainer Kaidan has been published under the Creative Commons license "Attribution-Share Alike 2.1 Japan," so a person can create a new version even for commercial use under the same license. The exhibition period of the Gainer Kaidan ended on March 9th 2008, but it will be recreated by another person (scheduled in April 2008). In this way, the Gainer Kaidan is not a static media installation piece, but a dynamic platform for media arts based on the Creative Commons license.

The whole source code of the Gainer Kaidan system