How to Make a Bug Sweeper

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Build your own radio frequency device to detect bugs.

Bug sweepers are electronic devices that are used to detect listening devices or bugs installed in a room. They work by detecting the radio frequency signals that are transmitted and received by the bugging device. If you believe that someone is listening in on conversations, then you can purchase a bug detection device; however if you like to tinker and build things yourself, then you can make your own bug sweeper to detect a listening device.


Step 1

Put all of your equipment on a large table. This will help prevent things from getting lost.

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Step 2

Strip the insulation off the 41 AWG copper wiring using the wire cutters. Turn the wire around the end of a toothpick 20 times. This will create a coil. Glue one end of the coil to the toothpick, and allow the glue to dry so that the coil will not loosen up.

Step 3

Get the brass tube and run the other end of the copper wire through it. Measure a half inch of a wire from the end of the tube. If there is any insulation on it, peel it off using the wire stripper.


Step 4

Work on the BNC connector. Inspect the stripped end of the 41-AWG copper wire. Connect the first wire to the positive terminal of the BNC connector and the other wire to the negative terminal of the BNC connector. Solder the connections. Stick the BNC connector to the brass tube using bonding glue.

Step 5

Apply a dollop of glue to the outer side of the toothpick coil. Insert it into the brass tube. The coil should be attached to the brass tube. To do this, push the glued side of the coil to the side of the tube.


Step 6

Get the RF Voltmeter and locate its female BNC connector. Connect the BNC connector to the female BNC connector for the RF voltmeter. Tighten the connection by turning the screws.

Step 7

Turn on the voltmeter and do a test. Turn your cell phone on and make a phone call. Place the RF voltmeter nearby. You will see an increase in signal. Mark the number on the voltmeter when the cell phone was transmitting.

Step 8

Walk around with the brass tube in your hand. Check if there is a change on the meter comparable to when the cellphone was transmitting. If there is, you may have an active bug in that area.

Things You'll Need

  • 0.9-inch brass tube

  • 41-AWG copper wire

  • Toothpick

  • Wire stripper

  • Glue

  • Soldering iron and lead