Dub Siren Synth Does It The Old School Way

November 29, 2019 by 18 Comments

There’s little that can compare to the sheer obnoxious thrill of mashing the DJ siren when its your turn behind the decks. We’ve certainly been guilty of abusing the privilege at local house parties, and unsurprisingly have not been invited back. If we ever get another shot, though, we’d be glad to have [lonesoulsurfer]’s dub siren at the ready.

This is a build for the old-school purists. There’s no microcontrollers or digital hardware here. The synth relies on two 555 timer ICs as the oscillators and an LM741 op-amp. These parts harken right back to the dawn of the integrated circuit era, and still do a great job in this application. There’s also a cheap reverb/echo module added in to fatten up the sound. It’s all laced up in an old CB radio enclosure, with the classic woodgrain applique doing much to add to the aesthetic.

It’s a build that’s simple enough for the electronics beginner, and would make a great tactile, analog addition to any DJ’s rig. If you need some wubwubs to go with your woowoos, then consider building a Ball of Dub, too.

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Landbeest, A Single Servo Walking Robot

November 29, 2019 by 14 Comments

Walking robots have a rich history both on and off the storied pages of Hackaday, but if you will pardon the expression, theirs is not a field that’s standing still. It’s always pleasing to see new approaches to old problems, and the Landbeest built by [Dejan Ristic] is a great example.

It’s a four-legged walker with a gait dictated by a cam-and-follower mechanism that allows it to perform the full range of leg movement with only one motor. Each cam can control more than one leg in synchronisation, and in his most recent prototype, there are two such mechanisms that work on opposite corners of a four-legged machine. The legs are arranged in such a way that the two corner-to-corner pairs pivot at their centres in a similar manner to a pair of scissors; allowing a servo to steer the robot as it walks.

The result certainly isn’t as graceful as [Theo Janssen]’s Strandbeest, from which it evidently takes inspiration for its name, but it’s no less capable for it. After the break you can see a video he’s posted which clearly illustrates its operation and demonstrates its ability to traverse obstacles.

The only thing that’s missing are the files and software should you wish to create your own. He’s unapologetic about this, pointing out that he’d prefer to wait until he is satisfied with it before letting it go. Since he’s put a lot of work in so far and shows no sign of stopping, we’re sure he’ll reach that point soon enough.

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DSP Spreadsheet: Talking To Yourself Using IQ

November 29, 2019 by 12 Comments

We’ve done quite a bit with Google Sheets and signal processing: we’ve generated signals, created filters, and computed quadrature signals. We can pull all that together into an educational model for two SDRs talking to each other, but it’s going to require two parts: modulation and demodulation. Guess what? We can do that with a spreadsheet.

The first step is to generate a reference clock for the carrier. You’ll need a cosine wave (I) and sine wave (Q). Of course, you also need the time base. That’s columns A-C in the spreadsheet and works like other signal generation we’ve seen.

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A Fantastic Frontier Of FPGA Flexibility Found In The 2019 Supercon Badge

November 29, 2019 by 7 Comments

We have just concluded a successful Hackaday Superconference where a highlight for many was digging into this year’s hardware badge. Shaped in the general form of a Game Boy handheld gaming console, the heart of the badge is a large FPGA opening up new and exciting potential for badge hacking.

Beyond our normal tools of compiling custom code or modifying hardware with a soldering iron, we now have the option to change core hardware behavior with Verilog. And people explored this new frontier to great effect, as seen at the badge hacking ceremony. (Video embedded below.)

FPGAs are not new, technically speaking, why are they exciting now? We can thank their recent growth in capability, their rapidly falling cost, and the relatively new availability of open source toolchains. These developments elevated FPGA into one of the most exciting trends in hardware today, so this year’s badge master [Sprite_TM] built an open FPGA playground for several hundred of his closest Supercon friends. Let’s take a look at what people were able to accomplish in just a few days using this unique and powerful hardware.

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Simplified AI On Microcontrollers

November 29, 2019 by 6 Comments

Artificial intelligence is taking the world by storm. Rather than a Terminator-style apocalypse, though, it seems to be more of a useful tool for getting computers to solve problems on their own. This isn’t just for supercomputers, either. You can load AI onto some of the smallest microcontrollers as well. Tensorflow Lite is a popular tool for this, but getting it to work on your particular microcontroller can be a pain, unless you’re using an Espruino.

This project adds support for Tensorflow to this class of microcontrollers without having to fuss around with obtuse build tools. Basically adding a single line of code creates an instance, all without having to compile anything or even reboot. Tensorflow is a powerful software tool for microcontrollers, and having it this accessible now is a great leap forward.

So, what can you do with this tool? The team behind this build is using Tensorflow on an open smart watch that can be used to detect hand gestures and many other things. They also opened up these tools for use in a browser, which allows use of the AI software and emulates an Espruino without needing a physical device. There’s a lot going on with this one, and it’s a bonus that it’s open source and ready to be turned into anything you might need, like turning yourself into a Street Fighter.

That’s It, No More European IPV4 Addresses

November 29, 2019 by 83 Comments

When did you first hear concern expressed about the prospect of explosive growth of the internet resulting in exhaustion of the stock of available IP addresses? About twenty years ago perhaps? All computers directly connected to the internet must have an individual unique address, and the IPv4 scheme used since the 1980s has a 32-bit address space that provides only 4,294,967,296 possibilities. All that growth now means that IPv4 addresses are now in short supply, and this week RIPE, the body which allocates them in Europe, has announced that it no longer has any to allocate. Instead of handing new address blocks they will instead now provide ones that have been relinquished for example by companies that have gone out of business, and parties interested can join a waiting list.

Is the Internet dead then? Hardly, because of course IPv6, the replacement for IPv4, has been with us for decades and has a much larger 128-bit address space. The problem is that there is a huge installed base of IPv4 infrastructure which has always been cited as the reason to delay its adoption, so the vast majority of the internet-connected world has remained with IPv4. Even in an IPv4 world there are opportunities to be more efficient in the use of addresses such as the network address translation or NAT that many private networks use to share one address between many hosts, so it’s not quite curtains for your smart TV or IoT light bulb even though the situation will not get any easier.

The mystery comes in why after so many years we still use IPv4 so much. Your home router and millions like it will pick up an IPv4 address from your broadband provider’s pool, and there seems little reason why it can not instead pick up an IPv6 address and contain a gateway between the two. The same goes for addresses outside the domestic arena, and even in out community we find that IPv6 networks at events are labelled as experimental. Perhaps this news will spur the change, but meanwhile we don’t expect to be using an IPv6 address day-to-day very soon.

We know among Hackaday’s readership there will be people close to the coalface when it comes to IPv6 adoption. As always the comments are open, and we’d like to hear your views.

Header: Robert.Harker [CC BY-SA 3.0].

Your WiFi Signals Are Revealing Your Location

November 28, 2019 by 43 Comments

The home may be the hearth, but it’s not going to be a place of safety for too long.

With the abundance of connected devices making their ways into our homes, increasing levels of data may allow for more accurate methods for remote surveillance. By measuring the strength of ambient signals emitted from devices, a site can be remotely monitored for movement. That is to say, WiFi signals may soon pose a physical security vulnerability.

In a study from the University of Chicago and the University of California, Santa Barbara, researchers built on earlier studies where they could use similar techniques to “see through walls” to demonstrate a proof-of-concept for passive listening. Attackers don’t need to transmit signals or break encryptions to gain access to a victim’s location – they just need to listen to the ambient signals coming from connected devices, making it more difficult to track bad actors down.

Typically, connected devices communicate to an access point such as a router rather than directly with the Internet. A person walking near a device can subtly change the signal propagated to the access point, which is picked up by a receiver sniffing the signal. Most building materials do not block WiFi signals from propagating, allowing receivers to be placed inconspicuously in different rooms from the access point.

WiFi sniffers are relatively inexpensive, with models running for less than $20. They’re also small enough to hide in unsuspecting locations – inside backpacks, inside a box – and emit no signal that could be detected by a target. The researchers proposed some methods for safeguarding against the vulnerability: insulating buildings against WiFi leakage (while ensuring that desirable signals, i.e. signals from cell tower are still able to enter) or having access points emit a “cover signal” that mixes signals from connected devices to make it harder to sniff for motion.

While we may not be seeing buildings surrounded by Faraday cages anytime soon, there’s only going to be more attack surfaces to worry about as our devices continue to become connected.

[Thanks to Qes for the tip!]