Technology to restore voice from bulb vibration?

A research team at Ben Gurion University reports a system lampphone that can eavesdrop on conversation sounds in a room by measuring the vibration of a light bulb from a distance without installing a camera or tapping device in the room where the subject is located.

Lampphone is a system that allows you to hear sounds from tens of meters away using a laptop, telescope, and sensor. It costs about $1,000. It is said that all sound in the room can be restored by simply checking the location of the light bulb without the need to hack or install equipment by restoring the small vibration sound generated from the light bulb glass surface.

In the experiment conducted by the research team, a telescope was installed 25m away from the room where the light bulb was suspended, and a photodetector PDA100A2 was installed on the telescope eyepiece, a sensor that captures the vibration of the bulb. A sensor that listens to music or plays a voice in a room retrieves the vibration value from the light bulb and outputs the restored voice to the PC in real time. The sensor used can detect vibrations of hundreds of microns in the bulb.

According to reports, only light bulbs hanging from cables were able to restore the voice, and whether it was possible to restore voice from light bulbs fixed to the ceiling or wall has not been confirmed. Also, in the experiment, since the speaker volume was at the maximum when playing voice or music, it was not known whether or not a small sound conversation could be detected by light bulb vibration. In this experiment, the research team claimed that relatively inexpensive equipment was used, so using expensive equipment that can detect delicate vibrations can restore even small voice conversations from light bulb vibrations. Related information can be found here .