So you need to hear the secrets that are being spilled in the building across the street? If the conversation is happening over the phone you could build a DIY Telephone Listening Bug and tune into the conversation on a radio but what if the conversation is happening between two people in the room? The answer is a Laser Listening Device, we have featured one of these DIY Laser Listening Devices in the past but this project article by Lucid Science is laid out and explained better.
The idea is that sound from someone speaking will vibrate the window that is in the same room as them. If you bounce a laser beam from a 5mW laser module off the window the laser beam will be deflected slightly as the window vibrates. If you monitor this vibration you will be able to hear what is being said.
Via: HG Comments
