Ham Radio Trips Circuit Breakers

Arc-fault circuit breakers are a boon for household electrical safety. The garden-variety home electrical fire is usually started by the heat coming from a faulty wire arcing over. But as any radio enthusiast knows, sparks also give off broadband radio noise. Arc-fault circuit interrupters (AFCI) are special circuit breakers that listen for this noise in the power line and trip when they hear it. The problem is that they can be so sensitive that they cut out needlessly. Check out the amusing video below the break.

Our friend [Martin] moved into a new house, and discovered that he could flip the breakers by transmitting on the 20-meter band. “All the lights in the place went out and my rig switched over to battery. I thought it was strange as I was certainly drawing less than 20 A. I reset the breakers and keyed up again. I reset the breakers again and did a [expletive] Google search.” Continue reading “Ham Radio Trips Circuit Breakers”

Jamming WiFi by Jumping on the ACK

As we fill our airwaves with more and more wirelessly connected devices the question of what could disrupt this systems becomes more and more important. Here’s a particularly interesting example because the proof of concept shows that you don’t need specialized hardware to pull it off. [Bastian Bloessl] found an interesting tweak to previous research that allows an Atheros WiFi card to jam WiFi by obscuring ACK frames.

The WiFi protocol specifies an Acknowledgement Frame (ACK) which is sent by the receiving device after error correction has been performed. It basically says: “yep, I got that data frame and it checks out”. This error correcting process turns out to be the key to [Bastian’s] technique as it provides time for the attack hardware to decide if it’s going to jam the ACK or not.

The jamming technique presented by [Mathy Vanhoef] at the end 2014 outlined both constant and selective jamming. The selective part involved listening for data packets and analyzing them to determine if they are headed to a MAC the attacker wishes to jam. The problem is that by the time your commodity hardware has decoded that address it’s too late to jam the packet. [Bastian] isn’t trying to jam the data frame, he’s jamming the ACK that the receiver sends back. Without that acknowledgement, the sender will not transmit any new data frames as it assumes there is a problem on the receiving end.

SDR and Node.js Remote-Controlled Monster Drift

Most old-school remote controlled cars broadcast their controls on 27 MHz. Some software-defined radio (SDR) units will go that low. The rest, as we hardware folks like to say, is a simple matter of coding.

So kudos to [watson] for actually doing the coding. His monster drift project starts with the basics — sine and cosine waves of the right frequency — and combines them in just the right durations to spit out to an SDR, in this case a HackRF. Watch the smile on his face as he hits the enter key and the car pulls off an epic office-table 180 (video embedded below).

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Reprogramming Bluetooth Headphones for Great Justice

Like a lot of mass-produced consumer goods, it turns out that the internal workings of Bluetooth headphones are the same across a lot of different brands. One common Bluetooth module is the CSR8645, which [lorf] realized was fairly common and (more importantly) fairly easy to modify. [lorf] was able to put together a toolkit to reprogram this Bluetooth module in almost all of these headphones.

This tip comes to us from [Tigox] who has already made good use of [lorf]’s software. Using the toolkit, he was able to reprogram his own Bluetooth headphones over a USB link to his computer. After downloading and running [lorf]’s program, he was able to modify the name of the device and, more importantly, was able to adjust the behavior of the microphone’s gain which allowed him to have a much more pleasant user experience.

Additionally, the new toolkit makes it possible to flash custom ROMs to CSR Bluetooth modules. This opens up all kinds of possibilities, including the potential to use a set of inexpensive headphones for purposes other than listening to music. The button presses and microphones can be re-purposed for virtually any task imaginable. Of course, you may be able to find cheaper Bluetooth devices to repurpose, but if you just need to adjust your headphones’ settings then this hack will be more useful.

[Featured and Thumbnail Image Source by JLab Audio LLC – jlabaudio.com, CC BY-SA 4.0]

Bluetooth Automation Remote Hangs Around

Using your smartphone to control your home automation system gives you a lot of flexibility. But for something as simple as turning the lights on and off, it can be a pain to go through the whole process of unlocking your phone, choosing the right browser page or app, and then finally hitting the button you need. It’d be much simpler if it could all be done at the touch of a single, physical button – but phones don’t have many of those anymore. [falldeaf] brings the solution – a four-button Bluetooth remote for your smartphone that’s wearable, to boot.

The project is built around the RFDuino, an Arduino platform used for quickly and easily building Bluetooth compatible projects. So far, so simple – four buttons wired into a microcontroller with wireless capability onboard. The real trick is the 3D-printed clothespin style case which allows you to clip the four-button remote onto your clothes. [falldeaf]’s first attempt was a palm-mounted setup that they found got in the way of regular tasks; we agree that the wearable version offers a serious upgrade in utility.

The smartphone side of things is handled with a custom app [falldeaf] coded using PhoneGap. This is where actions for the buttons can be customized, including using the buttons to navigate a menu system to enable the user to select more than just one function per button. It adds a high level of flexibility, so you can create all kinds of macros to control your whole home automation system from your button clip.

It’s really great to see a project that considers ergonomics and usability above and beyond just creating the baseline functionality. Follow this train of thought and you’ll find yourself enjoying your projects in the use phase well beyond the initial build. Another great example is this self-charging electrically heated jacket. Video after the break.

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Voltmeter Speaks MQTT Without Libraries

[Emilio Ficara] [built himself an Internet-connected MQTT multimeter](http://ficara.altervista.org/) (translated from Italian by robots). Or maybe we should say that [Emilio Ficara] undertook a long string of cool hacks that ended up in a WiFi-enabled multimeter, because the destination isn’t nearly as interesting as the voyage.

debugtool-sch

The multimeter, a DT-4000ZC, has a serial output but instead of transferring the data directly, it sends which cells on the LCD screen need to be activated. For testing along the way, [Emilio] used his own USB-serial-to-ESP01 dongle, which sounds like a useful tool to have around if you’re debugging an AT command session. He made a cute AVR SPI-port debugging aid with a reset button and diagnostic LEDs that we’re going to copy right now. Other home-made tools, like a 3.7V Li-ion battery manager and a serial data snooper make this project worth a look.

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Remote Controlling A Dog

Until the industrial revolution, humans made use of animals to make our labor easier. This is still seen in some niche areas, like how no machine yet has been invented that’s as good at sniffing out truffles as pigs are. [William] has hearkened back to humanity’s earlier roots, but in a more modern twist has made something of a general purpose dog that could feasibly do any work imaginable. Now his dog is remote-controlled.

[William] accomplished the monumental task in a literally cartoonish fashion using the old trope of hanging a hot dog in front of something’s face to get them to chase it. The attachment point was fitted with a remote control receiver and an actuator to get the hanging hot dog to dangle a little bit more to the dog’s right or left, depending on where the “operator” wants the dog to go. [William]’s bulldog seems to be a pretty good sport about everything and isn’t any worse for wear either.

Believe it or not, there has been some actual research done into remote controlling animals, although so far it’s limited to remote-controlled cockroaches. We like the simplicity of the remote-controlled dog, though, but don’t expect to see these rigs replacing leashes anytime soon!

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