Pest Control Bag Tag

Introduction: Pest Control Bag Tag

About: Hello I'm a hobbyist and crafts enthusiast. I love to share things I know would help solve a certain problem. Hope to share more instructables for you all!

This project is a simple pest control upgrade for your loved backpacks.

The ultrasonic sound waves emitted is safe to humans and may offend pest such as rodents, mosquitoes and cockroaches.

Please see following instructions to see how the project was done.

Step 1: The Circuit

The circuit is basically a 555 timer configured as astable multivibrator.

Frequency calculated based from R1, R2 and C1 values is around 43-kHz (above human threshold of 20kHz).

The output of 555 timer is fed to a piezoelectric buzzer creating the ultrasonic effect. The circuit is powered by two CR2032 button cells connected in series providing 6V supply.

Step 2: Materials and Tools

Here are the tools and materials I used to complete this project:


- 555 timer (IC1)

- 15k Ohms resistor (R2)

- 3.3k Ohms resistor (R1)

- 10nF mylar capacitor (C2 and C4)

- 1nF mylar capacitor (C1)

- 0.47uF electrolytic capacitor (C3)

- SPST Switch (SW1)

- Piezoelectric Buzzer (PS1)

- Key Chain (optional)

- Universal PCB

- Wires

- IC holders

- CR2032 Button cell and Holder


Soldering Iron

Wire Stripper

Soldering lead

Hack saw (optional)

Step 3: Dry Fit the Components

Assemble the parts to the universal PCB. The circuit layout is dry fitted to maximized space that allow it to look like a small back pack tag.

Step 4: Assemble Components and Start Soldering

Solder the leads once installed to the PCB. Start with the small parts since it will be difficult for it to be soldered if the big parts comes first. Cut the excess leads of each component.

Step 5: Wire the Circuit

This time wire the components based from the schematic given. Use of a smaller gauge wire is advisable. Cut any excess PCB using hacksaw.

Step 6: Done!

Lastly put in the battery and add a key chain or any alike for it to be installed in a back pack.

Now the pest control back pack tag is done and ready for use.

Thanks and hope you enjoyed.

Backpack Challenge

Participated in the
Backpack Challenge

Be the First to Share


    • Cheese Challenge

      Cheese Challenge
    • Metal Contest

      Metal Contest
    • Crayons Challenge

      Crayons Challenge



    4 years ago

    Empirically, it has no effect on mosquitoes. A 15kHz wave propagating in air is only good for annoying young kids (who can hear higher frequencies than adults).

    I looked into this about a month ago. Please cite relevant research if you found otherwise.


    Reply 4 years ago

    This device is working on the ultrasonic range (~43kHz). Haven't mentioned a 15kHz frequency in the instructions as you have mentioned.


    Question 4 years ago

    No offense, but using ultrasound to repel mosquitoes seems kinda gimmicky. Does this actually work? Enough to wear in the evening in Minnesota? Without bug spray?


    Answer 4 years ago

    The ultrasonic effect seemed to annoy them since it emits sound at their audible range. also the effectiveness of the device depends on the area it could cover.. I have brought one of these before and label says it could cover a small room keeping mosquitoes at bay...Try and see for yourself I guess..