A team of designers from the Oslo School of Architecture and Design has created a device that can produce a large scale visualization of the fluctuating Wi-Fi signals around a city.

Their latest prototype is a four-meter-tall rod, lined with LEDs that incorporates a microcontroller, Wi-Fi device, computer program, and Wi-Fi module to reveal its signal strength, displayed by lighting up an appropriate number of LEDs.

The signal reading is updated every three seconds so a changing bar made of lights is produced as the user walks around with the rod. By setting up a locked-off camera with a long exposure, a light painting that looks like a bar graph is produced over time.