DIY Listening Devices

Make a listening device from a pair of old headphones.

There are many reasons you may need to build your own listening device. Whether you want to catch a cheating lover in the act or install a surveillance system in your house, making a listening device could be the solution to your problems. And on the plus side, building it can make for a fun weekend project.

Things You'll Need

• Headphones
• Wire cutters or strippers
• Soldering iron
• Cadmium sulfide photocell
• Digital recorder
• Duct tape
• Laser pointer
• Tripod

Instructions

1. Cut the wire off your headphones. Carefully strip the plastic covering off the headphone jack to expose the red, black and white wires. Solder the red and white wires together to one of the two contacts on the cadmium sulfide photocell. Solder the black wire to the other contact on the cadmium sulfide photocell.

2. Plug the headphone jack into the digital recording device. Duct tape the photocell to a sturdy surface that can be moved and adjusted.

3. Attach the laser pointer to your tripod. Duct tape down the power button so it stays on.

4. Place this setup in the room you want to record in, discrete or not. Point the laser on the tripod at a window. Locate where the laser reflects to and place the photocell there so the point of the laser shines directly on the center front of the photocell.

5. Press record on the digital recorder. Now when people talk in the room or if noise is made, the window will vibrate. This vibration will be captured by the laser and transmitted to the photocell, turning on the recorder.

References

• DIY Life: DIY Laser Long-Distance Listening Device