Cybersecurity researcher Takeshi Sugawara found that it’s possible to make microphones respond to light as if it were sound. By pointing a laser at the microphone and changing the intensity, the light somehow influences the microphone’s membrane at the same frequency as the laser. The researchers then changed the intensity of the laser to match the frequency of a human’s voices to “speak” to the voice-activated devices. They found that all almost all the smart devices tested registered commands from up to 164 feet away. This has the potential to allow threat actors to purchase items and unlock doors silently through your window. The researchers even tried using infrared lasers, which are invisible to the naked eye, and found that it worked to activate certain smart devices. There are technical controls to prevent this, such as voice authentication and PIN numbers, but the best thing to do is keep the device out of the line of sight of any potential threats.
https://www.wired.com/story/lasers-hack-amazon-echo-google-home/