A Bold Experiment In A Decentralised Low Voltage Local DC Power Grid

January, for many of us in the Northern Hemisphere, can be a depressing month. It’s cold or wet depending where you live, the days are still a bit short, and the summer still seems an awfully long way away. You console yourself by booking a ticket to a hacker camp, but the seven months or so you’ll have to wait seems interminable.

If you want an interesting project to look forward to, take a look at [Benadski]’s idea for a decentralised low voltage local DC power grid for the upcoming SHA 2017 hacker camp in the Netherlands. The idea is to create a network that is both safe and open for hacking, allowing those with an interest in personal power generation to both have an available low-voltage power source and share their surplus power with other attendees.

The voltage is quoted as being 42V DC +/- 15%, which keeps it safely under the 50V limit set by the European Low Voltage Directive. Individuals can request a single 4A connection to the system, and villages can have a pair of 16A connections, which should supply enough for most needs. Users will need to provide their own inverters to connect their 5V or 12V appliances, fortunately a market served by numerous modules from your favourite Far Eastern sales portal.

This project will never be the solution to all power distribution needs, but to be fair that is probably not the intention. It does however provide a platform for experimentation, collaboration, and data gathering for those interested in the field, and since it is intended to make an appearance at future hacker camps there should be the opportunity for all that built up expertise to make it better over time.

We’ve touched on this subject before here at Hackaday, with our look at the availability of standard low voltage DC domestic connectors.

Wind turbine image: Glogger (CC BY-SA 3.0) via Wikimedia Commons.

Shmoocon 2017: The Ins And Outs Of Manufacturing And Selling Hardware

Every day, we see people building things. Sometimes, useful things. Very rarely, this thing becomes a product, but even then we don’t hear much about the ins and outs of manufacturing a bunch of these things or the economics of actually selling them. This past weekend at Shmoocon, [Conor Patrick] gave the crowd the inside scoop on selling a few hundred two factor authentication tokens. What started as a hobby is now a legitimate business, thanks to good engineering and abusing Amazon’s distribution program.

The product in question is the U2F Zero, an open source U2F token for two-factor authentication. It’s built around the Atmel/Microchip ATECC508A crypto chip and is, by all accounts, secure enough. It’s also cheap at about $0.70 a piece, and the entire build comes to about $3 USD. All of this is hardware, and should be extremely familiar to the regular Hackaday reader. This isn’t the focus of [Conor]’s talk though. The real challenge is how to manufacture and sell these U2F dongles, a topic we looked in on back in September.

The circuit for this U2F key is basically just a crypto chip and a USB microcontroller, each of which needs to be programmed separately and ideally securely. The private key isn’t something [Conor] wants to give to an assembly house, which means he’s programming all these devices himself.

For a run of 1100 units, [Conor] spent $350 on PCB, $3600 for components and assembly, $190 on shipping and tariffs from China, and an additional $500 for packaging on Amazon. That last bit pushed the final price of the U2F key up nearly 30%, and packaging is something you have to watch if you ever want to sell things of your own.

For distribution, [Conor] chose Fulfillment By Amazon. This is fantastically cheap if you’re selling a product that already exists, but of course, [Conor]’s U2F Zero wasn’t already on Amazon. A new product needs brand approval, and Amazon would not initially recognize the U2F Zero brand. The solution to this was for [Conor] to send a letter to himself allowing him to use the U2F Zero brand and forward that letter to the automated Amazon brand bot. Is that stupid? Yes. Did it work? Also yes.

Sales were quiet until [Conor] submitted a tip to Hacker News and sold about 70 U2F Zeros in a day. After that, sales remained relatively steady. The U2F Zero is now a legitimate product. Even though [Conor] isn’t going to get rich by selling a dozen or so U2F keys a day, it’s still an amazing learning experience and we’re glad to have sat in on his story of bootstrapping a product, if only for the great tip on getting around Amazon’s fulfillment policies.

Shmoocon 2017: Software Defined Radio for Terahertz Frequencies

Before Bluetooth, before the Internet of Things, and before network-connected everything, infrared was king. In the 90s, personal organizers, keyboards, Furbys, and critical infrastructure was built on infrared. Some of these devices are still around, hiding in plain sight. This means there’s a lot of opportunities for some very fun exploits. This was the focus of [Mike Ossmann] and [Dominic Spill]’s talk at this year’s Shmoocon, Exploring The Infrared World. What’s the hook? Using software-defined radio with terahertz frequencies.

irtra
[Dominic]’s infrared detector
Infrared communication hasn’t improved since the days of IrDA ports on laptops, and this means the hardware required to talk to these devices is exceptionally simple. The only thing you need is an IR phototransistor and a 4.7k resistor. This is enough to read signals, but overkill is the name of the game here leading to the development of the Gladiolus GreatFET neighbor. This add-on board for the GreatFET is effectively a software defined IR transceiver capable of playing with IrDA, 20 to 60 kHz IR remote control systems, and other less wholesome applications.

Demos are a necessity, but the world seems to have passed over IR in the last decade. That doesn’t mean there still aren’t interesting targets. A week before Shmoocon, [Mike Ossmann] put out the call on Twitter for a traffic light and the associated hardware. Yes, police cars and ambulances use infrared signaling to turn traffic lights green. You shouldn’t. You can, but you shouldn’t.

What was the takeaway from this talk? IR still exists, apparently. Yes, you can use it to send documents directly from your PalmPilot to a laser printer without any wires whatsoever. One of the more interesting applications for IR is an in-car wireless headphone unit that sends something almost, but not quite, like pulse coded audio over infrared. The demo that drew the most applause was an infrared device that changed traffic lights to green. The information to do that is freely available on the web, but you seriously don’t want to attempt that in the wild.

Shmoocon 2017: Dig Out Your Old Brick Phone

The 90s were a wonderful time for portable communications devices. Cell phones had mass, real buttons, and thick batteries – everything you want in next year’s flagship phone. Unfortunately, Zach Morris’ phone hasn’t been able to find a tower for the last decade, but that doesn’t mean these phones are dead. This weekend at Shmoocon, [Brandon Creighton] brought these phones back to life. The Motorola DynaTAC lives again.

[Brandon] has a history of building ad-hoc cell phone networks. A few years ago, he was part of Ninja Tel, the group that set up their own cell phone network at DEF CON. That was a GSM network, and brickphones are so much cooler, so for the last few months he’s set his sights on building out a 1G network. All the code is up on GitHub, and the hardware requirements for building a 1G tower are pretty light; you can roll your own 1G network for about $400.

The first step in building a 1G network, properly referred to as an AMPS network, is simply reading the documentation. The entire spec is only 136 pages, it’s simple enough for a single person to wrap their head around, and the concept of a ‘call’ really doesn’t exist. AMPS looks more like a trunking system, and the voice channels are just FM. All of this info was translated into GNU Radio blocks, and [Brandon] could place a call to an old Motorola flip phone.

As far as hardware is concerned, AMPS is pretty lightweight when compared to the capabilities of modern SDR hardware. The live demo setup used an Ettus Research USRP N210, but this is overkill. These phones operate around 824-849 MHz with minimal bandwidth, so a base station could easily be assembled from a single HackRF and an RTL-SDR dongle.

Yes, the phones are old, but there is one great bonus concerning AMPS. Nobody is really using these frequencies anymore in the US. That’s not to say building your own unlicensed 1G tower in the US is legally permissible, but if nobody reports you, you can probably get away with it.

Shmoocon 2017: A Simple Tool For Reverse Engineering RF

Anyone can hack a radio, but that doesn’t mean it’s easy: there’s a lot of mechanics that go into formatting a signal before you can decode the ones and zeros.

At his Shmoocon talk, [Paul Clark] introduced a great new tool for RF Reverse Engineering. It’s called WaveConverter, and it is possibly the single most interesting tool we’ve seen in radio in a long time.

If you wanted to hack an RF system — read the data from a tire pressure monitor, a car’s key fob, a garage door opener, or a signal from a home security system’s sensor — you’ll be doing the same thing for each attack. The first is to capture the signal, probably with a software defined radio. Take this data into GNU Radio, and you’ll have to figure out the modulation, the framing, the encoding, extract the data, and finally figure out what the ones and zeros mean. Only that last part, figuring out what the ones and zeros actually do, is the real hack. Everything before that is just a highly advanced form of data entry and manipulation.

[Paul]’s WaveConverter is the tool built for this data manipulation. Take WaveConverter, input an IQ file of the relevant radio sample you’d like to reverse engineer, and you have all the tools to turn a radio signal into ones and zeros at your disposal. Everything from determining the preamble of a signal, figuring out the encoding, to determining CRC checksums is right there.

All of this is great for reverse engineering a single radio protocol, but it gets even better. Once you’re able to decode a signal in WaveConverter, it’s set up to decode every other signal from that device. You can save your settings, too, which means this might be the beginnings of an open source library of protocol analyzers. If someone on the Internet has already decoded the signals from the keyfob of a 1995 Ford Taurus, they could share those settings to allow you to decode the same keyfob. This is the very beginnings of something very, very cool.

The Github repo for WaveConverter includes a few sample IQ files, and you can try it out for yourself right now. [Paul] admits there are a few problems with the app, but most of those are UI changes he has in mind. If you know your way around programming GUIs, [Paul] would appreciate your input.

Shmoocon 2017: So You Want To Hack RF

Far too much stuff is wireless these days. Home security systems have dozens of radios for door and window sensors, thermostats aren’t just a wire to the furnace anymore, and we are annoyed when we can’t start our cars from across a parking lot. This is a golden era for anyone who wants to hack RF. This year at Shmoocon, [Marc Newlin] and [Matt Knight] of Bastille Networks gave an overview of how to get into hacking RF. These are guys who know a few things about hacking RF; [Marc] is responsible for MouseJack and KeySniffer, and [Matt] reverse engineered the LoRa PHY.

In their talk, [Marc] and [Matt] outlined five steps to reverse engineering any RF signal. First, characterize the channel. Determine the modulation. Determine the symbol rate. Synchronize a receiver against the data. Finally, extract the symbols, or get the ones and zeros out of the analog soup.

From [Marc] and [Matt]’s experience, most of this process doesn’t require a radio, software or otherwise. Open source intelligence or information from regulatory databases can be a treasure trove of information regarding the operating frequency of the device, the modulation, and even the bit rate. The pertinent example from the talk was the FCC ID for a Z-wave module. A simple search revealed the frequency of the device. Since the stated symbol rate was twice the stated data rate, the device obviously used Manchester encoding. These sorts of insights become obvious once you know what you’re looking for.

In their demo, [Marc] and [Matt] went through the entire process of firing up GNU Radio, running a Z-wave decoder and receiving Z-wave frames. All of this was done with a minimum of hardware and required zero understanding of what radio actually is, imaginary numbers, or anything else a ham license will hopefully teach you. It’s a great introduction to RF hacking, and shows anyone how to do it.

Shmoocon 2017: On Not Reverse Engineering Through Emulation

Right now, I’m at Shmoocon, and it’s living up to all expectations. That’s a tall order — last year, the breakout talk was from [Travis Goodspeed] on his efforts to reverse engineer the firmware for a cheap Chinese radio. Four people in the room for that talk last year bought the radio on Amazon, and now there’s a legitimate open source project dedicated to building firmware and tools to support this radio.

tyteraNow that [Travis] has a few compatriots working on firmware for this radio, he has the same challenges as any other team. The project needs unit tests, and this isn’t easy to do when all the code is locked up inside a radio. Instead of setting up an entire development platform based around a cheap radio, [Travis] came up with a toolchain that’s unlike anything I’ve ever seen. Instead of reverse engineering the firmware for this radio, he’s simply emulating the ARM firmware on the desktop. Development is quick and easy, and he has the live demos to prove it.

The heart of the Tytera radio in question is an STM32F405. This is a pretty common part, and thanks to [Travis]’ work last year, he has all the firmware that ships on this radio. This doesn’t mean he has access to all the radio’s capabilities, though; there’s a black box in the code somewhere that translates .wav files to radio packets and back again. Open sourcing this would usually mean reverse engineering, but [Travis] had a better idea.

Instead of reverse engineering the entire radio, [Travis] is using QEMU to emulate an ARM microcontroller on his desktop, run the relevant code, and completely ignore any actual reverse engineering. Since this radio is already jailbroken and the community has a pretty good idea of where all the functions and subroutines are in the firmware, the most difficult part of pulling this trick off is setting up QEMU.

As a proof of concept, [Travis] downloaded raw AMBE packets from the radio to his laptop. These were then sent through the emulated radio, producing raw audio that was then converted into a .wav file. Effectively, a black box in this radio was emulated, which means [Travis] doesn’t need to know how the black box works.

All the code for this weird emulation / unit test, as well as everything the community has released for this radio is available on the GitHub. A lot of work has gone into the jailbreaking, reverse engineering, and emulation efforts here, making this radio somewhat ironically one of the most open radios you can buy.