Home

Bombshock Turns 10!

To celebrate, I've launched operation overhaul, and are adding several hundred new fringe books to the archives.

I Need HELP! "Like" and share with your friends on facebook. Put a link to bombshock on your site or blog. That's All.

You Are Here: Home » Electronics Projects » Wireless Transmitters, Bugs & Taps » How To Build A Bug Detector

How To Build A Bug Detector

A lot of people face invasion of their privacy due to widespread use of the bugs in almost every place. To avoid this situation many people spend a lot of money on bug detectors as they do not know of How To Build A Bug Detector. Construction of a bug detecting device is not hard if a specific method is followed.

In How To Build A Bug Detector you will read a simple way to make a device that detects Infinity transmitters.

Basic theory:

Because most bugs are triggered through certain frequencies, it is very simple to build a small sweeping device that will trigger any bug present. The two IC’s are what create the oscillating tone. The IC1 operates at .8 Hz where the IC2 runs at about 10 Hz. Frequency is determined by this formula:

f=1.44/(R1+2R2)C)

f measured in Hertz, R in megohms, and C in microfarads

The oscillation can be varied by the voltage placed upon pin #5. This is how we create the wave sound. When voltage goes up, so does the frequency, and vice-versa.

Normally, the output pin 3 is a square wave. Since we need varying wave at pin #5, we need a triangular wave.We get this through integrating the square wave created at pin #3 of IC1. It is acheived by D1, D2, R3, R4 and C2.

This varying output is fed into the phone line by transformer T1 which has an 8 ohm winding going to pin #3 of IC2 and the 500 end to a 0.1 microfarad capaci- tator at the phone line.

Enuf talk..let’s get movin!

Schematic Design:

how to build a bug detector How To Build A Bug Detector

Parts List:

C1 : 10-uF electrolytic capacitator 25 WDVC
C2 :300-uF electrolytic capacitator 25 WDVC
C3 :0.1-uF capacitator
C4 :0.068-uF capacitator
D1-D3 : 1N914
IC1,IC2 555 timers
R1, R4-R6 : 1-kilohm resistors
R2 : 91-kilohm resistor
R3 : 22 kilohm resistor
T1 :500-to-8 ohm audio output transformer

Construction:

When building this unit, it is very useful to use a breadboard or vector board. I suggest that leads being connected to phone line (T1, C3) end in a jack or a modular connector to make the hookup easier. To test it, hook it to the phone line (not the suspected line) and call the line you suspect is being bugged. The party you are calling should not answer the phone.Now, the unit is activated. 3 times, every 4 seconds, the oscillator will go up to 10 kHz and back down again..like a bell curve..If there is a frequency sensitive bug on the line, the phone will stop ringing, and you will be able to hear everything said in the room. If the phone keeps ringing, chances are that all is fine..unless the bug requires a multi-frequency trigger..but these are very rare..

So, we can see that this really does work! It creates the tone..any click heard is the Phone Co’s (or whoever is bugging) speaker/tape recorder picking up!

Now you know How To Build A Bug Detector and you are also aware that building it is nothing very tough.


Comments (2)

  • jay

    Could you please post a better diagram and a pic of the finihsed detector on a bread board? Thanks.

  • John Dortch

    I have been a broadcast engineer for 45 years. I have see better schematics drawn by two year olds.

  • leecaddick2k8@gmail.com

    @Dave
    hay dave is there some chance that you could send me a pcb of a good fm wireless mic please i cant find any any where please also layout and parts list ty

  • am

    yes dave i totally agree with you mate it took me some time staring at that schematic before ieven ”realised” it was a schematic!

  • HBSkirmit

    On the schematic, you show pin 3 of the first 555 connected to D1 and R2.
    R2 should be corrected and relabeled as D2.

Leave a Comment

© 2013 bombshock.com

Scroll to top