Researchers Turn Smartphone Vibration Motor into Microphone
Two researchers from the University of Illinois at Urbana-Champaign have devised a method for turning vibration motors, like the ones found in smartphones, into makeshift microphones, capable of recording the sound around them.
Their method doesn't yield perfect results and also needs physical access to the device, but it puts in place the theoretical details needed to carry out and refine such attacks in the future.
The attack, named VibraPhone, is based on the idea that any vibration motor is technically a speaker. Vibration motors translate electrical current sent into sound waves by moving a coil. In this case, the coil generates vibrations and low humming sounds in the phone. Since a microphone is basically a reversed speaker, taking incoming sounds and converting them back into electrical waves, the researchers decided to attempt an experiment during which they turned a phone's vibration motor into a microphone.
