DIY Bug Detector Instructions

by | Spy Gear

Last Updated on March 12, 2021

Whether you travel often or you simply appreciate the peace of mind of knowing nobody is listening in on your conversations, the best bug detector can help you get that safety. It’s a device that’s a must for people who often spend a lot of time in hotel rooms, and If you’re looking to make one yourself, we’ve got just the right thing for you – a guide on making a DIY bug detector. And you may also want to check our learning guide as well on how to use a bug detector.

In terms of tools, you’ll need a hot glue gun and some glue, as well as a PCB clamp and magnifying glass. You’ll want to grab a small screwdriver to break up traces, as well as wire strippers and cutters, and a pair of needle nose pliers. And lest we forget, a soldering iron and solder, as well as a solder pump to solder everything to the PCB.

We’ll be following this schematic, and there you’ll also find a list of all components you will need as well, which shouldn’t cost more than $15 in total. This schematic is best printed, and you can then use that to grab a pegboard and cut it to the appropriate dimensions. The end goal is for the entire thing to fit inside an Altoids tin, so you will need to do a bit of cutting. With that out of the way, let’s start. (1)

Let’s begin

First, you’ll want to solder the capacitors. The board should be kept in the same orientation as the schematic, so you don’t make a mistake. This is going to simplify everything significantly.

Another thing to keep in mind is the polarity of the electrolytic capacitor. The negative side should be on the left, and you’ll notice it because it has a silver stripe. You should straighten out the leads in order for them to fit the board.

Insert the capacitors where necessary, and bend the leads on the other side to hold them in place. A good tip would be to bend the leads in the direction where you’ll be soldering, to keep things easier to track. Solder the leads.

Next, you have resistors. They’re all marked with a color code, and the R1 will have a value printed on it. Again, use the reference image to set everything right. Place the resistors, as well as the inductor, on the pegboard, and bend all the leads to keep things in place. Flip it over, and solder them in place.

The transistors are next, and you should be careful with the orientation. You should have the flat side facing the left of the board. Bend the leads out for Q4 to fit the board well, and again, bend them on the other side to be able to solder them more easily.

It’s time for the LED and diodes. You’ll need to know which is the cathode, and which is the anode. The cathode is the shorter lead on the LED, and it has a white line on the diode. On an LED, the cathode goes on the bottom of the board, and on a diode, it goes at the top. Use the trick of bending the leads to solder them in place.  

Up next we have the switch and the piezo buzzer. When you’re inserting the switch, make sure to spread out the leads a bit. This will make it fit just right, so the buzzer drops into place. Solder them to the pegboard.

The coil should be made with a copper wire, one you’ll bend around an object that has a 3mm diameter. Make the turns nice and tight, and use a bit of hot glue to keep things in place. When you’re done, you should strip the ends a bit. The antenna is basically a 100mm piece of wire, nothing complicated about it.

Time for the battery. Grab two pieces of wire, 10mm each, and bend them into two U-shaped pieces. Place them in the Pad1 area, as the schematic suggests, and place the battery clip. Solder it in place, which will let you insert the battery.

Let’s solder the traces now. Use the excess leads, but make sure you don’t bridge two traces that you shouldn’t be bridging – this might completely destroy the project. Grab pieces of wire if you need it for traces, and do things carefully, as you don’t want to be making a mistake with this.

The last step is to insert everything in the Altoids tin. Isolate the bottom, because it might short the board, and cut holes in the sides for the LED and the switch. Use hot-glue to secure the PCB to the tin, and voila, you’ve got your DIY bug detector!

If you are looking for a learning guide about RF bug detectors this time, then, start with this; What is an RF detector? I hope these learning guides help you!



About Gadgets Spy

Hi, I’m Michael, a security and surveillance expert. I co-founded and write for GadetsSpy and help teach people about new tech and Gadgets.