Unless you’re one of the cool people who uses the same password everywhere, you might be in need of a hardware device that keeps your usernames and passwords handy. The Passkeeper is a hardware password storage system built on a Raspberry Pi. It encrypts your passwords, and only through the magic of a special key fob will you ever get your passwords out of this device.
The hardware for this device is built around the Raspberry Pi Zero. You might be questioning the use of a Pi Zero, but given that it’s an entire Linux system for just a few bucks, it only makes sense. The rest of the hardware is a tiny OLED SPI display, an RFID card reader, a few LEDs, some wire, and some solder. A 3D printed case keeps everything together.
Of course, this build is all about the software, and for that, the Passkeeper device is built in Go, with a system that builds a web interface, builds the firmware, and writes everything to an SD card. Usage is simply plugging the Passkeeper into the USB port of your computer where it presents itself as a network interface. Everything is available by pinging an IP address, and after that the web UI will log your usernames and passwords. All this data is encrypted, and can only be unlocked if an RFID key fob is present. It’s an interesting idea and certinaly inexpensive. It’s not quite as polished as something like the Mooltipass, but if you have a Pi around and don’t have a password keeper, this is something to build this weekend.
One of the things that makes us human is our ability to communicate. However, a stroke or other medical impairment can take that ability away without warning. Although Stephen Hawking managed to do great things with a computer-aided voice, it took a lot of patience and technology to get there. Composing an e-mail or an utterance for a speech synthesizer using a tongue stick or by blinking can be quite frustrating since most people can only manage about ten words a minute. Conventional speech averages about 150 words per minute. However, scientists recently reported in the journal Nature that they have successfully decoded brain signals into speech directly, which could open up an entirely new world for people who need assistance communicating.
The tech is still only lab-ready, but they claim to be able to produce mostly intelligible sentences using the technique. Previous efforts have only managed to produce single syllables, not entire sentences.
Continue reading “Scientists Create Speech From Brain Signals” →
USB-C has been around for a while, and now that it can charge phones and Macbooks and Thinkpads, the hackers are starting to take note of power adapters that can supply lots of current. [Alex] was turned on to USB-C after he charged a laptop, Nintendo Switch, and phone with one power adapter. This led him to create a USB-C battery charger for all your LiPos.
The high-level design of this project is simply a board with a USB C port on one end, an XT60 plug on the other, and some support for balance leads. Plug this board into a USB C adapter, plug a battery in, and the battery will charge automagically. The only UI is an RGB LED. It’s difficult to imagine a battery charger that’s easier to use.
For the electronics, [Alex] is using an STM32G0 for the smarts of the device, which includes handling the USB PD spec. This gives the charger 20 Volts to play with, and this is then regulated and sent into the battery. Right now, this board will charge 2-4c batteries. That’s a good enough proof of concept to charge some quadcopter batteries, or just as a really simple way to charge some LiPo cells.
RFID payment systems are one of those things that the community seems to be divided on. Some only see the technology as a potential security liability, and will go a far as to disable the RFID chip in their card so that it can’t be read by a would-be attacker. Others think the ease and convenience of paying for goods by tapping their card or smartphone on the register more than makes up for the relatively remote risk of RFID sniffers. Given the time and effort [David Sikes] put into creating this contactless payment ring, we think it’s pretty clear which camp he’s in.
Alright, so the whole ring making part sounds easy enough, but how does one get an RFID chip that’s linked to their account? Easy. Just call the bank and ask them for one. Of course, they won’t just send you out a little RFID chip and antenna to mount in your hacked up project. (If only things were so simple!) But they will send you a new card if you tell them your old one is getting worn out and needs a replacement. All you have to do when it gets there is liberate the electronics without damaging them.
[David] found that an hour or so in an acetone bath was enough to dissolve the plastic and expose the epoxy-encased RFID chip, assuming you scrape the outer layers of the card off first. He notes that you can speed this part of the process up considerably if you know the exact placement and size of the RFID chip; that way you can cut out just the area you’re interested in rather than having to liquefy the whole card.
Once you have your chip, you just need to mount it into a ring. [David] has designed a 3D printable frame (if you’ve got a high-resolution SLA machine, that is) which accepts the chip and a new antenna made from a coil of 38 AWG magnet wire. With the components settled into the printed frame, its off to a silicone mold and the liberal application of epoxy resin to encapsulate the whole thing in a durable shell.
If a ring is not personal enough for you, then the next step is getting the RFID chip implanted directly into your hand. There are even folks at hacker cons who will do that sort of thing for you, if you’re squeamish.
Continue reading “RFID Payment Ring Made From Dissolved Credit Card” →
While at the Hacker Hotel camp in the Netherlands back in February, our attention was diverted to an unusual project. [Niklas Fauth] had bought along a Tesla coil, but it was no ordinary Tesla coil. Instead of the usual tall coil and doughnut-shaped capacity hat it took the form of a stack of PCBs with spacers between them, and because Tesla coils are simply cooler that way, he had it playing music as an impromptu MIDI-driven plasma-ball lousdpeaker. Now he’s been able to write up the project we can take a closer look, and it makes for a fascinating intro not only to double-resonant Tesla coils but also to Galium Nitride transistors.
The limiting factor on Tesla coils comes from the abilities of a transistor to efficiently switch at higher frequencies. Few designs make it above the tens of kHz switching frequencies, and thus they rely on the large coils we’re used to. A PCB coil can not practically have enough inductance for these lower frequencies, thus Niklas’ design employs a very high frequency indeed for a Tesla coil design, 2.6 MHz with both primary and secondary coils being resonant. His write-up sets out in detail the shortcomings of conventional MOSFETS and bipolar transistors in this application, and sets out his design choices in using the GaN FETs. The device he’s using is the TI LMG5200 GaN half-bridge driver, that includes all the necessary circuitry to produce the GaN FET’s demanding drive requirements.
The design files can be found in a GitHub repository, and you can see a chorus of three of them in action in the video below. Meanwhile [Niklas] is a prolific hardware hacker whose work has appeared on these pages in the past, so take a look at his ultrasonic phased array and his x-ray image sensor work.
Continue reading “A Tesla Coil From PCBs” →
To the average person, the application of balloon technology pretty much begins and ends with birthday parties. The Hackaday reader might be able to expand on that a bit, as we’ve covered several projects that have lofted various bits of equipment into the stratosphere courtesy of a high-altitude balloons. But even that is a relatively minor distinction. They might be bigger than their multicolored brethren, but it’s still easy for a modern observer to write them off as trivial.
But during the 1940’s, they were important pieces of wartime technology. While powered aircraft such as fighters and bombers were obviously more vital to the larger war effort, balloons still had numerous defensive and reconnaissance applications. They were useful enough that the United States Navy produced a training film entitled History of Balloons which takes viewers through the early days of manned ballooning. Examples of how the core technology developed and matured over time is intermixed with footage of balloons being used in both the First and Second World Wars, and parallels are drawn to show how those early pioneers influenced contemporary designs.
Even when the film was produced in 1944, balloons were an old technology. The timeline in the video starts all the way back in 1783 with the first piloted hot air balloon created by the Montgolfier brothers in Paris, and then quickly covers iterative advancements to ballooning made into the 1800’s. As was common in training films from this era, the various “reenactments” are cartoons complete with comic narration in the style of W.C. Fields which were designed to be entertaining and memorable to the target audience of young men.
While the style might seem a little strange to modern audiences, there’s plenty of fascinating information packed within the film’s half-hour run time. The rapid advancements to ballooning between 1800 and the First World War are detailed, including the various instruments developed for determining important information such as altitude and rate of climb. The film also explains how some of the core aspects of manned ballooning, like the gradual release of ballast or the fact that a deflated balloon doubles as a rudimentary parachute in an emergency, were discovered quite by accident.
When the film works its way to the contemporary era, we are shown the process of filling Naval balloons with hydrogen and preparing them for flight. The film also talks at length about the so-called “barrage balloons” which were used in both World Wars. Including a rather dastardly advancement which added mines to the balloon’s tethers to destroy aircraft unlucky enough to get in their way.
This period in human history saw incredible technological advancements, and films such as these which were created during and immediately after the Second World War provide an invaluable look at cutting edge technology from a bygone era. One wonders what the alternative might be for future generations looking back on the technology of today.
Continue reading “Retrotechtacular: Balloons Go To War” →
Every few years, or so we’re told, [Scott] revisits the idea of building an electrocardiogram machine. This is just a small box with three electrodes. Attach them to your chest, and you get a neat readout of your heartbeat. This is a project that has been done to death, but [Scott]’s most recent implementation is fantastic. It’s cheap, relying on the almost absurd capability for analog to digital conversion found in every sound card, and the software is great. It’s the fit and finish that makes this project shine.
The hardware for this build is simply an AD8232, a chip designed to be the front end of any electrocardiogram. This is then simply connected to the microphone port of a sound card through a 1/8″ cable. For the exceptionally clever, there’s a version based on an op-amp. It’s an extraordinarily simple build, but as with all simple builds the real trick is in the software. That’s where this project really shines, with custom software with graphics, and enough information being displayed to actually tell you something.
We’ve seen a number of sound card ADCs being used for electrocardiograms in the past, including some from the Before Times; it makes sense, sound cards are the cheapest way to get a lot of analog data very quickly. You can check out [Scott]’s demo video out below.
Continue reading “Sound Card ADCs For Electrocardiograms” →