Norwegian designers Timo Armall, Jørn Knutsen, and Einar Sneve Martinussen visually capture invisible WiFi signals by light painting signal strength in long-exposure photographs. The trio set up a four-meter long WiFi-detecting rod with 80 LED bulbs to depict cross-sections through the WiFi networks of various Oslo neighborhoods. Armall says:
"After a week of walking through urban spaces holding and photographing this instrument, we have a much better sense of the qualities of WiFi in urban spaces, its random crackles, bright and dim spots, its reaction to the massing of buildings, and its broad reach through open areas. The resulting images show some of these qualities, and light painting is a brilliant medium for situating visualisations and data into physical world locations and situations."