Rootkid's Spectrum Slit Lights Up Any Room with the Cheery Glow of Visualized Radio Spectrum

Pseudonymous maker and artist "Rootkid" has built a unique wall-mounted light called the Spectrum Slit, which is designed to respond to the local radio environment, targeting the 2.4GHz and 5GHz spectra.

"Spectrum Slit is a sculptural installation that renders visible the otherwise imperceptible electromagnetic activity that permeates contemporary interior spaces," its creator explains. "While a room may appear visually calm and silent, it is continuously traversed by dense fields of radio-frequency transmissions generated by wireless communication technologies. This work exposes that hidden layer of reality by translating radio wave activity into light (and sound) in real time."

The light itself is a long, rectangular affair made up of 64 luminous filaments — behind which, at one end, you can see a Great Scott Gadgets' HackRF One software-defined radio. "Unlike traditional radios which are designed for a specific frequency," Rootkit explains, "software-defined radios are driven by software. This means I can tune in and listen to any frequency within their operating range."

While the HackRF One can handle frequencies as low as 10MHz and as high as 6GHz, Rootkid's sculpture focuses on the two bands most common in modern households: 2.4GHz and 5GHz, as used by Wi-Fi and Bluetooth devices. Data from the HackRF One are sent to a Raspberry Pi Zero 2 W single-board compute for processing, and then used to drive the lamp's 64 filaments in a pattern inspired by scientific frequency plots.

"The resulting display is dynamic and situational," Rootkid says. "At moments of low network usage, the sculpture emits faint, intermittent light, reflecting the ambient background noise of an urban environment. As wireless activity increases — through web browsing, video streaming, messaging, or connected devices — the filaments surge and saturate, forming dense bands of intense illumination. The sculpture thus becomes a temporal portrait of collective digital behavior, shaped by the rhythms of daily life."

The project is documented in the video embedded above and on Rootkid's YouTube channel, with more information available on the maker's website.