Think your smartphone’s microphone is the only way hackers can eavesdrop on your conversations?

Think again.

University of Illinois Urbana-Champaign researchers found that the vibration motors on smartphones and wearables (such as fitness bands) can be engineered to record sound vibrations from someone’s voice, which can be reconstructed into waveforms.

This isn’t something that can be done remotely, but researchers Romit Roy Choudhury and Nirupam Roy of UIUC engineering, say that the mechanical process to rewire the vibration motors would only take a minute or so. Later, malware could be installed that can listen in on any conversation. After being processed, they found recordings become intelligible, “to the extent that humans can understand the vibra-motor recorded words with greater than 80 percent average accuracy” they wrote in a paper that will be presented next month.

Gulp.

The good news? Choudhury and Roy are not hackers, and in fact their research centers on ways to anticipate the various ways that technology can be hacked so engineers can find ways to prevent it from happening. Previously Choudhury created an app that could guess which words a smartwatch wearer was typing, using data gathered from the motion sensors in the watch.

And their findings weren’t all so ominous. Choudhury and Roy also pointed out that their findings could be used to develop further applications for smartphones and wearables, such as voice activated fitness bands and improved microphone function in smartphones.

You can explore their work through the research website.