Back in the day, an FM bug was a handy way to make someone’s annoying radio go away, particularly if it could be induced to feedback. But these days you’re far more likely to hear somebody’s Bluetooth device blasting than you are an unruly FM radio.
To combat this aural menace, [Tixlegeek] is here with a jammer for the 2.4 GHz spectrum to make annoying Bluetooth devices go silent. While it’s not entirely effective, it’s still of interest for its unashamed jankiness. Besides, you really shouldn’t be using one of these anyway, so it doesn’t really matter how well it works.
Raiding the AliExpress 2.4 GHz parts bin, there’s a set of NRF24L01+ modules that jump around all over the band, a couple of extremely sketchy-looking power amplifiers, and a pair of Yagi antennas. It’s not even remotely legal, and we particularly like the sentence “After running the numbers, I realized it would be cheaper and far more effective to just throw a rock at [the Bluetooth speaker]“. If there’s a lesson here, perhaps it is that effective jamming comes in disrupting the information flow rather than drowning it out.
This project may be illegal, but unlike some others we think it (probably) won’t kill you.
Holy moly, just get 4 2.4ghz ‘video transmitters’ set them to different channels and bob is your uncle. Use a wok pan for directionality!
Or defeat the interlock on your microwave oven and leave the door open.
This may also keep your targets coffee warm while taking out their Bluetooth and brain cells.
Retina would go out first, I think?
“Do not look in the waveguide with the remaining eye” ?
I note that he doesn’t say whether it did actually jam his neighbour’s speaker. BT can be surprisingly resilient to non-wideband jamming attacks.
Nope, it didn’t. I found the range to be at most 2m 😄
“This project may be illegal, but unlike some others we think it (probably) won’t kill you.”
Unless you’re a diabetic that relies on bluetooth comms from your glucometer and insulin pump.
That is why you add “Your mileage may vary…” at the end ;)
i would be ok if the FCC camped by dude’s house and knocked on the door as soon as the jammer was turned on.
“i would be ok if the FCC camped…”
So many well known entrepreneurs were once hackers and the thinking process, the design process, and maybe even the construction of a “potentially bad” device DOES NOT correlate to illegal offences and potential punishment. The human animal often finds that the enrichment of knowledge follows a path to a working prototype. What happens AFTER the prototype is constructed determines the label: Good or Evil.
Case study:
http://spectrum.ieee.org/zone-of-silence
We aren’t supposed to emit harmful interference to other users in the ISM bands, but on the flip side their receivers must tolerate any interference they receive. So, the odds of ever being rousted for jamming are about zero for any device emitting power less than that required to fog your eyeballs.
Jammers do have one advantage that he did not mention. Unlike analog, digital protocols do not need to be disrupted continuously. If you’re clever you can desyncronize the receiver and transmitter and they link will be broken for some time, potentially seconds. That means you can focus your power into bursts, and at single frequencies to obtain MUCH higher peak output, even though the average is still low. Alas this does rule out simple “noisy” jammers.
I still like this project though. Legality aside, the reality is that technology is used very often for evil. Open source counter-measures are important.