What waveform should I use to drive the VCO and why?
Generate a near-linear sawtooth that peaks at ≥4 V. Linear ramps keep the VCO sweeping evenly; steep edges cause missed bands and silence [Elektroda, Seps111, post #20241242]
DIY bluetooth jammer, bluetooth jammer - final project
TL;DR
- DIY 2.4 GHz jammer targets Bluetooth and Wi‑Fi as a low-cost final project.
- The circuit uses a LiPo-powered MT3608L supply, with pads for charging, external output, and calibration of the sweep signal.
- It claims 2100–2600 MHz sweep coverage, about 5–10 mW output, and optional 100 mW or 1 W amplification for more range.
- Effectiveness depends strongly on distance, and the post warns that Wi‑Fi or Bluetooth interference is illegal and intended only for private use against spy devices.
A simple but effective 2.4 GHz jammer. This module can block BT and Wi-Fi. I designed it so that the cost of its implementation was as low as possible due to the semiconductor crisis. The circuit includes a simple astable multivibrator with a square wave to saw converter for generating the VCO control signal. The 5.1V power supply is provided by the MT3608L converter, so the device can be powered by any LiPo battery, but please make sure the battery can supply at least 500mA of current, if you want to use the amplifier, the current must be at least 1A. The VCO generates the sweep signal in the range 2100-2600 MHz. The output power is about 5-10mW, you can use an amplifier if you want more range. The CHRG fields are used to charge the battery, the 5V out pad is used to connect an external device, e.g. an amplifier. The SWEEP OUT pad is used to calibrate the output wave, the ADJ potentiometer adjusts the waveform, the correct signal should look something like this:
To emit a signal, a biquad antenna works best, I attach a link with an interesting article on how to make it and a model for printing a 3d antenna frame
https://buildyourownantenna.blogspot.com/2014...-biquad-sector-antenna-for-2450-mhz-wifi.html
3D printing model: https://www.thingiverse.com/thing:4734227
To disrupt the signal, point the jammer at the receiver, remember that the effectiveness of the interference depends on the distance between the transmitter and receiver. When the phone is 20 cm from the loudspeaker, jamming is almost impossible, but when the phone is 2 m away, the jammer can easily block the signal within a range of several to several meters.
An example of a 1W amplifier: https://pl.aliexpress.com/item/10050023541036..._list.0.0.37e01c24IXT8Uk&gatewayAdapt=glo2pol
Cheaper 100 mW amplifier: https://a.aliexpress.com/_EJz6Zs5
VCO used: https://pl.aliexpress.com/item/1005002503822581.html
You can use a model other than YSGM232508, such as SV2450 or SM2400, the pinout should look like this:
Schematic diagram:
Tile appearance:
Assembly diagram:
Mounting holes spacing:
In the attachments I include the GERBER file to order the board and the list of materials (BOM), if, for example, you want a PDF file for etching or purchase a printed circuit board (boards sold out!), I invite you to a private chat.
Please remember that interference with Wi-Fi or bluetooth is illegal, a device for private use only to block, for example, spy devices (webcam, listening loudspeaker). The author is not responsible for improper use of the jammer, post and the information contained therein solely for educational purposes.
To emit a signal, a biquad antenna works best, I attach a link with an interesting article on how to make it and a model for printing a 3d antenna frame
https://buildyourownantenna.blogspot.com/2014...-biquad-sector-antenna-for-2450-mhz-wifi.html
3D printing model: https://www.thingiverse.com/thing:4734227
To disrupt the signal, point the jammer at the receiver, remember that the effectiveness of the interference depends on the distance between the transmitter and receiver. When the phone is 20 cm from the loudspeaker, jamming is almost impossible, but when the phone is 2 m away, the jammer can easily block the signal within a range of several to several meters.
An example of a 1W amplifier: https://pl.aliexpress.com/item/10050023541036..._list.0.0.37e01c24IXT8Uk&gatewayAdapt=glo2pol
Cheaper 100 mW amplifier: https://a.aliexpress.com/_EJz6Zs5
VCO used: https://pl.aliexpress.com/item/1005002503822581.html
You can use a model other than YSGM232508, such as SV2450 or SM2400, the pinout should look like this:
Schematic diagram:
Tile appearance:
Assembly diagram:
Mounting holes spacing:
In the attachments I include the GERBER file to order the board and the list of materials (BOM), if, for example, you want a PDF file for etching or purchase a printed circuit board (boards sold out!), I invite you to a private chat.
Please remember that interference with Wi-Fi or bluetooth is illegal, a device for private use only to block, for example, spy devices (webcam, listening loudspeaker). The author is not responsible for improper use of the jammer, post and the information contained therein solely for educational purposes.
Seps111 wrote 143 posts with
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Live in city Kielce.
Been with us since 2018 year.
Comments
Cool design, does the wave shape strongly affect the "effectiveness" of the operation? [Read more]
The waveform should be as linear as possible, keeping in mind that the peak voltage should be at least 4 V (then the VCO adjusts to 2500 MHz). By turning the ADJ potentiometer, not only the shape but also... [Read more]
Why did you choose the astable multivibrator? Eyes hurt from looking at this thing on T3. When the slider reaches the collector, the transistor ends its life. [Read more]
I chose the multivibrator because it is quite simple and cheap in construction, it works perfectly for my requirements. With this T3 you rightly noticed, a stupid oversight on my part. However, surprisingly,... [Read more]
Need a battery for power? A LiPo battery is the better choice if it's going to be small. The battery in a cylindrical housing 18650 is an even better choice, because it is capacious and gives more... [Read more]
It works effectively above my expectations, even on a mini omnidirectional antenna, soon tests on the one recommended by the author of the project ;) [Read more]
How efective IT is and at what range? [Read more]
Can you send me a file in jlc format? Added after 1 [minutes]: Can you send me a file in jlc format? My email address is 1761140303@qq.com Added after 26 [minutes]: @Seps111 Can you send me a... [Read more]
I'm interested in your project. Could you sent me a copy of no panelized (just single board) Gerber file? So that I can use the production discounts from JLC. Thank you so much for sharing. (My email address:... [Read more]
I really appreciate your solution; it's elegant and straightforward! I've noticed the addition of a component and I'm curious about its purpose. https://obrazki.elektroda.pl/2689354400_1714289418_thumb.jpg... [Read more]
Hi, May I have a JLC format file? thanks. my e-mail: 1287892228@qq.com, thanks a lot. [Read more]
You can't, I've made the file available in GERBER format if you want to order a disc. Added after 1 [minute]: The additional resistor is used to protect transistor T3 from too much current... [Read more]
Hello, I assembled exactly the same device as yours, but it doesn’t jam anything. Could this be due to an incorrect output from the multivibrator? I am attaching the photo below. https://obrazki.elektroda.pl/5939649300_1716144713_thumb.jpg... [Read more]
The slope of the control signal is too steep, adjust it to look like the one in my picture at the beginning of the forum topic. Make sure you use the correct antenna and verify that the VCO is soldered... [Read more]
What voltage does the step-up inverter produce? I think you have the resistor divider wrong - in your case it is before the diode, it should be after the diode. [Read more]