DVB-S From A Raspberry Pi With No Extra Hardware

April 3, 2016 by 19 Comments

An exciting aspect of the trend in single board computers towards ever faster processors has been the clever use of their digital I/O with DSP software to synthesize complex signals in the analogue and RF domains that would previously have required specialist hardware. When we use a Raspberry Pi to poll a sensor or flash an LED it’s easy to forget just how much raw processing power we have at our fingertips.

One of the more recent seemingly impossible feats of signal synthesis on a Raspberry Pi comes from [Evariste Courjaud, F5OEO]. He’s created a DVB-S digital TV transmitter that produces a usable output direct from a GPIO pin, with none of the external modulators that were a feature of previous efforts required. (It is worth pointing out though that for legal transmission a filter would be necessary.)

DVB is a collection of digital TV standards used in most of the world except China and the Americas. DVB-S is the satellite version of DVB, and differs from its terrestrial counterpart in the modulation scheme it employs. [Evariste] is using it because it has found favor as a digital mode in amateur radio.

This isn’t the first piece of [F5OEO] software creating useful radio modes from a GPIO pin. He’s also generated SSB, AM, and SSTV from his Pi, something which a lot of us in the amateur radio community have found very useful indeed.

We’ve covered digital TV creation quite a few times in the past on these pages, from the first achievement using a PC VGA card almost a decade ago to more recent Raspberry Pi transmitters using a USB dongle and a home-built modulator on the GPIO pins. Clever signal trickery from digital I/O doesn’t stop there though, we recently featured an astoundingly clever wired Ethernet hack on an ESP8266, and we’ve seen several VHF NTSC transmitters on platforms ranging from the ESP to even an ATtiny85.

Thanks [SopaXorzTaker] for the nudge to finally feature this one.

Hacking Flappy Bird By Playing Mario

April 3, 2016 by 24 Comments

This is a hacking and gaming tour de force! [Seth Bling] executed a code injection hack in Super Mario World (SMW) that not only glitches the game, but re-programs it to play a stripped-down version of “Flappy Bird”. And he did this not with a set of JTAG probes, but by using the game’s own controller.

There are apparently a bunch of people working on hacking Super Mario World from within the game, and a number of these hacks use modified controllers to carry out the sequence of codes. The craziest thing about our hack here is that [Seth] did this entirely by hand. The complete notes are available here, but we’ll summarize the procedure for you. Or you can go watch the video below. It’s really incredible.

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Bike Power Meter With Crank-mounted WiFi Strain Gauges

April 3, 2016 by 35 Comments

In any motorsport, the more you know about how the engine is performing, the better a driver is likely to do in a race. That holds for bicycles, too, where the driver just happens to also be the engine. There are plenty of cheap bike computers on the market, but the high-end meters that measure power output are a bit pricey. [chiprobot] is looking to change that with a home-brew, low-cost bike power meter.

The project still appears to be in the proof-of-concept phase, but it’s an interesting concept for sure. The stock crank arms are carefully fitted with two pairs of tiny strain gauges. The gauges are wired in a Wheatstone bridge arrangement, with one gauge in each pair mounted perpendicular to the force on the crank to serve as a static reference. Output from the bridge is fed to an HX711 instrumentation amplifier. The demo video below shows how sensitive the bridge and 24-bit amp are.

The goal is to send crank data to a handlebar-mounted UI via WiFi with a pair of ESP8266 modules. We like the idea of a bicycle area network, but [chiprobot] has his work cut out for him in terms of ruggedizing and weatherproofing all this gear. We’ll be sure to keep an eye on this project. In the meantime, there’s plenty to learn from this bike power meter project we covered last year.

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Raspberry Pi As Speed Camera

April 3, 2016 by 110 Comments

Wherever you stand on the topics of road safety and vehicle speed limits it’s probably fair to say that speed cameras are not a universally popular sight on our roads. If you want a heated argument in the pub, throw that one into the mix.

But what if you live in a suburban street used as a so-called “rat run” through route, with drivers regularly flouting the speed limit by a significant margin. Suddenly the issue becomes one of personal safety, and all those arguments from the pub mean very little.

Sample car speed measurements
Sample car speed measurements

[Gregtinkers]’ brother-in-law posted a message on Facebook outlining just that problem, and sadly the local police department lacked the resources to enforce the limit. This set [Gregtinkers] on a path to document the scale of the problem and lend justification to police action, which led him to use OpenCV and the Raspberry Pi camera to make his own speed camera.

The theory of operation is straightforward, the software tracks moving objects along the road in the camera’s field of view, times their traversal, and calculates the resulting speed. The area of the image containing the road is defined by a bounding box, to stop spurious readings from birds or neighbours straying into view.

He provides installation and dependency instructions and a run-down of the software’s operation in his blog post, and the software itself is available on his GitHub account.

We’ve had a lot of OpenCV-based projects but haven’t featured a speed camera before here on Hackaday. But we have had a couple of dubious countermeasures, like that humorous attempt at an SQL injection attack, or a flash-based countermeasure.

Turning An Angle Grinder Into A Belt Sander

April 3, 2016 by 23 Comments

Faced with a project requiring a lot of sanding, [George] had two options. Suck it up and buy a belt sander — or re-purpose a tool he already had to do the same job. He chose the latter, and turned an angle grinder into a belt sander.

Part of a series called Make It Extreme on YouTube, [George] built the entire project from scratch using raw materials. Using a lathe he created the aluminum rolling dowels the sanding belt will sit on. He pressed bearings into them, and then welded up a frame using scrap steel to hold them apart. He’s even added a spring-powered tension device to ensure the belt stays on.

As for mounting the angle grinder in place, it couldn’t be easier. It slides in between two metal guides, and attaches using the threaded hole for the angle grinder’s handle.

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Paper Enigma Machine

April 2, 2016 by 6 Comments

It was high-tech encryption for an important period of time in the mid-1940s, so perhaps you can forgive us our obsession with the Enigma machine. But did you know that you can make your very own Enigma just using some cut out paper strips and a tube to wrap them around? Yeah, you probably did. But this one is historically accurate and looks good too!

If you just want to understand how the machine worked, having a bunch of paper rolls in your hands is a very intuitive approach. Alan Turing explained the way it worked with paper models too, so there’s no shame there. With this model, you can either make the simple version with fixed rotor codes, or cut out some extra slip rings and go all out.

What is it with Hackaday and the Enigma machine? Just last month, we covered two separate Enigma builds: one with a beautiful set of buttons and patch cables, and another in convenient wrist-watch format. In fact, one of our first posts was on a paper Enigma machine, but the links are sadly lost to bitrot. We figure it’s cool to repeat ourselves once every eleven years. (And this one’s in color!)

Hack Corporate Overlords For Single Button Beer Delivery

April 2, 2016 by 9 Comments

[Brody Berson] is at it again, but this time he’s hacked the services floating in the aether around him to give him beer on demand. Finally the future we’ve been waiting for.

This hack is not as hacky as his first one, which, at the push of a button, could summon a bad driver straight to his house who would then give him pizza. The first one was done with a modified version of a button used to summon paper towels; because there’s nothing like needing paper towels RIGHT NOW, and then pushing a button to get them a few days later.

Apparently Amazon saw how practically no one was pushing the dish detergent button, but a lot of people were making scary mailboxes and magic pizza apps after ruthlessly scratching the branding off. So they shrugged and decided to sell the buttons as the newly branded (these get more hilarious when you don’t use the acronyms) Amazon, Amazon Web Services Internet of Things Button. Now your button can die along with the internet because Amazon is hosting your Raspberry Pi for a small fee, neat.

Anyway, [Brody] did some research on the best beer delivery services in his area, and went with one called Drizzly because they had a nice API. After integrating this system with Amazon’s, he can now push a button and minutes later, after subtracting some currencies from his account, a bad driver will show up and hand him beer.