It sounds like something out of a sci-fi movie—a ghostly voice coming through the radio, repeating strange sentences like “The birch canoe slid on the smooth planks.”
But it’s not supernatural.
It’s your own smart devices unknowingly giving away your private conversations.
Researchers from the University of Florida and the University of Electro-Communications in Japan have discovered a surprising new security flaw.
Microphones in laptops, smart speakers, and other common electronics can accidentally leak your voice using weak radio signals.
These signals are not meant to be broadcast, but they are strong enough to pass through walls and can be picked up by basic radio equipment.
The researchers demonstrated how these hidden signals can be captured using a simple FM radio receiver and a copper wire as an antenna—materials that cost less than $100.
Even more unsettling, the recordings they captured from another room or through thick concrete walls were still understandable, thanks to software that cleans up the static.
At the heart of the issue are MEMS microphones, short for microelectromechanical systems. These small, cheap microphones are built into most modern electronics.
As they process sound, they unintentionally release tiny amounts of radio frequency energy. These emissions contain traces of whatever the microphone is hearing—conversations, meetings, music, and more.
Even when you’re not actively using a microphone, apps like YouTube, Spotify, Amazon Music, or Google Drive can enable it in the background. That means your devices might be listening more often than you think—and unintentionally sending out those signals for others to catch.
The research team tested a variety of devices, including laptops, video conferencing headsets, and a Google Home speaker. Laptops turned out to be the most vulnerable because their microphones are often connected to long wires, which act like antennas and boost the signal’s strength.
To prove how easy it is to exploit the flaw, the team used artificial intelligence tools to clean up and transcribe the radio signal recordings. The software could even search for specific words, making it easier to sift through conversations.
The good news is that fixing the problem doesn’t require expensive solutions. Moving the microphone closer to the circuit board or using shorter cables could reduce the signal strength. Updating the way microphones process audio could also make the leaked signals harder to understand.
The researchers have already shared their findings and suggestions with electronics manufacturers. Whether companies act on these warnings remains to be seen. Until then, this surprising vulnerability serves as a reminder that even our most ordinary devices might be sharing more than we realize.
Source: University of Florida.
