Revealing inherently invisible and abstract data on a computer screen is one thing. But making it immediate and tangible in physical reality is another. There have been a few great attempts to accomplish just that, such as those that revealed the Readable Volume in the Field of a RFID Reader, or Overlaying Urban Images with Wireless Technology. This project is the next step, larger and more spatially relevant as never before.
By combining a stick full of WiFi sensor-connected LED lights with a long-term photo exposure, Timo Arnall, Jørn Knutsen and Einar Sneve Martinussen achieved a physical life-size bar graph of sorts in their project "Immaterials: Light painting WiFi" [yourban.no].
In essence, they built a 4-meter long WiFi measuring rod that visualizes the overall WiFi signal strength as a bar of lights on a specific location. When moved through space, the rod displays the changes in the WiFi signal by changing the number of the lights that light up. As a result, long-exposure photographs of the moving rod reveal cross sections of a network's signal strength. The light of the measuring rod pulses as it is being moved, which creates dashed lines rather than solid ones. This creates a semi-transparent texture that allows the visualization to appear within the physical setting without covering it.
Via Flowing Data.