iWall: An Illuminated Façade For Smart Lighting Research




The iWall was an interactive light installation that opened up new opportunities in Smart Lighting research, teaching, and development for researchers, students, artists and makers. It was installed high up along the entire façade of the Computer Science building at RWTH Aachen University, facing Halifaxstraße. The iWall installation opened to the public in December 2013. It was on display until 2022, when the sun protection panels were removed to make room for a renovated façade.

The iWall was designed so users could interact with it outside the building using their mobile devices. The iWall was part of the Aixplorer project that was working on future approaches to city guide systems for tourists. Interactive façades are becoming commonplace in urban spaces, and future mobile city guide systems have an opportunity to use such displays to provide additional channels for information, art, and entertainment to tourists.

Why the iWall for Smart Lighting Research?

  • The iWall was a permanently visible statement about the importance and potential of photonics, right at a major research hub, visible to students, faculty, and visitors. Thousands of students from one of Germany's top-ranked computer science departments were exposed to it on a daily basis, pointing them towards photonics and smart lighting as an exciting field to study and conduct research in.
  • The challenges of real-time content delivery, networking, synchronization, video display, power supply solutions, interactivity, sensor usage, and many other related photonics and smart lighting topics were explored by students and researchers both while constructing the iWall and when writing new apps for it.

Respecting A Historic Building

The CS building is a protected historical building from the 1950s that used to host the "Pädagogische Hochschule", so special care was taken to find a solution for designing and installing the iWall so that it was completely invisible when looking at the façade during daytime. Only at nightfall, the illumination became noticeable. Even then, the iWall did not use direct LED point lights which would have created a cheap, amusement park-like look. Instead, its LEDs were mounted behind the permanent sun reflector panels that spanned the entire width of the building. The LEDs pointed downwards at an angle, thus indirectly illuminating the street-facing outside of the next sun reflector panel below with a soft glow. This created larger, more subdued and elegant illumination effects and a spatially continuous impression.

Unique Format: 1920x10 — A FullHD Strip

The building constraints led to an unusual format for the iWall: With a dot pitch of about 3 cm over the width of 60 meters, it featured 1920 RGB LED pixels of horizontal resolution, while the existing sun reflector structure only allowed for 10 RGB LED pixels of vertical resolution at a dot pitch of about 20 cm, for a height of about 2 meters. This unique format — FullHD horizontal, but only 10 pixels vertical — challenged the designers of content and interactive applications for the display. At the same time, this elegant "illuminated band" perfectly fit the existing architecture, underlining its original design intentions.

A Smart Lighting Research Platform

The iWall was not just a passive, automated display showing meaningless animations, however. Instead, we created an API and programming interface so that researchers, students, artists and makers could turn the iWall into a tool for their own ideas and projects. The entire array of 20,000 RGB LEDs could be individually controlled at framerates fast enough for completely smooth animated effects. A first workshop for these developers was included in this project. Here are just some sample ideas for directions that projects using the iWall could take:

  • Implement a side-scrolling game that people can play by connecting to the iWall online using their smartphone: Waving your phone up and down (or shouting, or...) controls your character while you try to evade the many obstacles coming towards you.
  • Have the stars of 80's video games parade the length of the CS building - Super Mario, PacMan gobbling pills,... (the original Lemmings game characters were only 10 pixels high!)
  • Provide a real-time collaborative drawing app that lets users doodle on the wall using their smartphone or tablet. Content slowly fades away after a while unless it's liked through social media.
  • Visualize the number of internet-connected devices currently in the building (or energy consumption, or illuminated offices, or...) in a scrolling graph view - complete with a history view of the past 24 hours
  • Use the elongated wall banner to display a local weather status and forecast based on live internet data
  • Artists can design reactive animations that detect sounds, or measure environmental parameters like light or humidity using local sensors we install, and that visualize the effects of changes in beautiful, serene patterns.
  • Play back video content at a full 30 fps — what kind of video material works on such a wide display?
  • Create a real-time, low-resolution "mirror" of the environment captured by a low-resolution image sensor; reflecting people walking by, cars passing, and other effects, in a stylized fashion, without invading privacy.
  • Show a low-resolution live view of people moving around the inside of the building, to make the building's façade "transparent".
  • Instead of the local environment, show a live street scene from a partner university somewhere in the world instead.
  • Provide a serene "signature" illumination effect that identifies the Computer Science building, similar to existing RWTH buildings like SuperC, Heizkraftwerk and others.
  • Of course the iWall can also display traditional text — over 50 detailed characters along its length. Application ideas: Provide real-time pointers for visitors at events ("Enter here for graduation ceremony ->"), for public transport ("Next bus: Line 30 to Melaten arriving in 5 min "), etc.

We knew that students, artists and other makers, given the opportunity, would come up with countless even more creative ideas to breathe life into this unusual display.

During one annual "Tag der Informatik" graduation party, for example, we turned the iWall into an interactive chat board that users could send messages to using their smartphones.


Prof. Jan Borchers: Project idea

Dr. Thorsten Karrer: Senior Project Lead, driver development

René Bohne: Mechanics consulting

Jan Zimmermann: Mechanics, mountings

Sascha Schade: Electronics and software

Niklas Hauser: Electronics and software

Simon Jakubowski: Mobile app and web server development


  • Oct 14, 2013: While getting out of bed, Jan B. thinks a CS media façade would be cool. Initial discussions with Niklas in the lab.
  • Oct 17, 2013: Project kickoff with Mario, Jan Z., René, Jan B. at Dorkbot meeting. Tested mounting an LED strip to one of the sun reflectors, looks great at night.
  • Dec 6, 2013: Tag Der Informatik takes place, organized by i10; iWall scheduled to be up and running.
  • March 2014: Simon Jakubowski completes his Bachelor thesis developing a software infrastructure for mobile iWall apps
  • November 2014: Niklas Hauser overhauls the iWall hardware and wired communication protocols
  • Summer 2022: After nearly ten years, the iWall is disassembled to make room for a modernized building façade. 

Internal Project Pages — registered access only

We use cookies on our website. Some of them are essential for the operation of the site, while others help us to improve this site and the user experience (tracking cookies). You can decide for yourself whether you want to allow cookies or not. Please note that if you reject them, you may not be able to use all the functionalities of the site.