Smartphones are receptors for wireless signals, but they’re typically displayed as a series of bars. Turn those bars into a color app, and you’ve got an instant art display, capable of being the object of colorful time-lapse photography.
They’re called Spirit Photographs, or Wireless Spectre. The project is a performance art piece by Newscastle University student Luis Herman. The photos demonstrate the nuances of invisible wireless waves as perceived by our mobile devices and moved by humans. In order to capture the wireless signals as colors, the light performers used the Kirlian Device, an app that expresses wireless signal strengths with screen colors.
The current version of the app continuously reads the WiFi manager status, looks for the Received Signal Strength Index (RSSI) of the current connection and transforms the value into the corresponding color from a five-color heat map scheme. Red means stronger signal, blue means weaker. In addition, it uses the RSSI value to emit a changing frequency sine-wave tone. The app maps values between -40 and -90 dB, but it is possible to adjust this threshold by pressing the “Calibrate” button provided in the main interface.
Just a note: the app does not take photos. It simply shows WiFi strength as colors. In order to re-create the ghostly images, you’ll need to experiment with some time-lapse photography and a tripod. Another thing to keep in mind is the color of the WiFi spectrum. If you find yourself seeing a lot of blue, that’s actually a bad sign.