DIY Laser Listening Device
- 1). Mount a laser pointer on the tripod. A laser pointer can be purchased at an office supply store for about $5 as of 2010.
- 2). Get an old set of headphones and strip off the coating on the wire to expose the three wires: red, black and white. Connect the photocell to the wire using a soldering iron. There are two contacts connecting both the red and white wires to one contact, and the black wire to the other. A photocell can be bought in any electronics store for $0.30 each. Solder one pin of the photocell to the red and white wires of the headphones and the other pin to the black wire.
- 3). Clip the photocell, soldered to a wire, to another tripod or portable base such as a book.
- 4). Point the headphone jack to the microphone port of a laptop, recorder or MP3 player, depending on what you will decide to use.
- 5). Turn your laser on and point it to your target window. Clip the laser "On" button to ensure that it will be on throughout the process.
- 6). Position the photocell so that it will hit or catch the reflection made by the laser pointer. Any noise inside the room will trigger the window to vibrate. The vibration causes reflections from the laser pointer. The photocell catches the reflections and transmits it to the recorder. You may want to add a filter to your system to remove unwanted noise such as scratches or humming.
- 7). Put on your headphones and begin listening to any conversation in the room.
