This Wall Art Displays Ambient Radio Waves

A fact of modern life is that we’re all constantly surrounded by manmade radio waves — not to mention those from natural sources. There isn’t anywhere on the surface of the planet where you won’t be exposed to at least some. But because we can’t see them or feel them, we tend to forget that they’re there. So, Rootkid built this wall art that displays those ambient radio waves.

Rootkid was particularly interested in the part of the electromagnetic spectrum we use for communications, which includes most of the radio range and into the microwave range. Even small cities will be absolutely inundated with activity in those ranges, so there is plenty to see.

To create this wall art, Rootkid had to accomplish two things: detecting the radio waves and displaying a visualization of what is detected.

The former was easy enough to do with a Raspberry Pi Zero 2 W single-board computer that scans for signals through a HackRF One SDR (software-defined radio) device. Because it doesn’t need to actually connect to anything, the HackRF One can simply tell the Raspberry Pi what it “sees” across its capable range, which extends from 1MHz to 6GHz.

The visualization part was more complicated, but also more fun. Because this is art and not some kind of measurement instrument, Rootkid was able to play around with the data to get a result that looks nice. That is a visualization consisting of many blinking LED filaments, with frequencies corresponding to detected signals across the range.

The finished product looks kind of like an EQ visualizer, but for radio waves. The cool part is that it reflects local communications. Upload a big file nearby over Wi-Fi and you’ll probably see a corresponding jump on the display. Late at night, when most people are asleep, it will show minimal activity — though there is always at least some, since radio waves are ever-present.