Hackaday Prize Entry: Electric Variable Pitch Props

April 3, 2017 by 39 Comments

Barring the smallest manned airplanes, most aircraft that are pulled around by a prop have variable pitch propellers. The reason for this is simple efficiency. Internal combustion engines are most efficient at a specific RPM, and instead of giving the engine more gas to speed up, pilots can simply change the pitch of a propeller. With a gas powered engine, the mechanics and design of variable pitch propellers are well understood and haven’t really changed much in decades. Adding variable pitch props to something pulled around by an electric motor is another matter entirely. That’s what [Peter McCloud] is building for his entry to the Hackaday Prize, and it’s going into the coolest project imaginable.

This project is designed for a previous Hackaday Prize entry, and the only 2014 Hackaday Prize entry that hasn’t killed anyone yet. Goliath is a quadcopter powered by a lawnmower engine, and while it will hover in [Peter]’s test rig, he’s not getting the lift he expected and the control system needs work. There are two possible solutions to the problem of controlling the decapatron: an ingenious application of gimballed grid fins, or variable pitch rotors. [Peter] doesn’t know if either solution will work, so he’s working on both solutions in parallel.

[Peter]’s variable pitch rotor system is basically an electronic prop mount that connects directly to the driven shafts on his gas-powered quadcopter. To get power to the electronics, [Peter] is mounting permanent magnets to the quad’s frame, pulling power from coils in the rotor hub, and rectifying it to DC to drive the servos and electronics. Control of the props will be done wirelessly through an ESP32 microcontroller.

Variable pitch props are the standard for everything from puddle jumpers to acrobatic RC helis. In the quadcopter world, variable pitch props are at best a footnote. The MIT ACL lab has done something like this, but perhaps the best comparison to what [Peter] is doing is the incredible Stingray 500 quad. Flite Test did a great overview of this quad (YouTube), and it’s extremely similar to a future version of the Goliath. A big motor (in the Stingray’s case, a brushless motor) powers all the props via a belt, and the pitch of the props is controlled by four servos. The maneuverability of these variable pitch quads is unbelievable, but since the Goliath is so big and has so much mass, it’s doubtful [Peter] will be doing flips and rolls with his quads.

You can check out a video of [Peter]’s build below.

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LEGO Liquid Handler And Big Biology

April 3, 2017 by 6 Comments

A career as a lab biologist can take many forms, but the general public seems to see it as a lone, lab-coated researcher sitting at a bench, setting up a series of in vitro experiments by hand in small tubes or streaking out a little yeast on an agar plate. That’s not inaccurate at all – all of us lab rats have done time with a manual pipettor while trying to keep track of which tube in the ice bucket gets which solution. It’s tedious stuff.

But because biology experiments generally scale well, and because more data often leads to better conclusions, life science processes can quickly grow beyond what can be handled manually. I’ve seen this time and again in my 25 years in science, from my crude grad school attempts to miniaturize my assays and automate data collection to the multi-million dollar robotic systems I built in my career in the pharmaceutical industry. Biology can get pretty big in a hurry. Continue reading “LEGO Liquid Handler And Big Biology” →

VCF East: Enigma Machines In The Flesh

April 3, 2017 by 13 Comments

At the end of World War II, the Germans ordered all Enigma cipher machines destroyed. Around the same time, Churchill ordered all Enigma cipher machines destroyed. Add a few decades, neglect the efforts of Polish codebreakers, and make a movie about Alan Turing and an offensively historically incorrect love interest, and you have a mystique around these rare, innovative cipher machine.

At the Vintage Computer Festival East, I was privy to what is probably the largest collection of Enigma machines on the planet. The exhibit comes from [Tom] and [Dan Perera] of Enigma Museum. Right now, they’re they only place where you can go out and simply buy a real, wartime Enigma machine. The price? Well, there is a pair of million-dollar Apple I boards at VCF. The Enigmas go for about a fifth of an Apple I.

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When The Grid Goes Dark

April 3, 2017 by 92 Comments

If you lived through the Y2K fiasco, you might remember a lot of hype with almost zero real-world ramifications in the end. As the calendar year flipped from 1999 to 2000 many forecast disastrous software bugs in machines controlling our banking and infrastructure. While this potential disaster didn’t quite live up to its expectations there was another major infrastructure problem, resulting in many blackouts in North America, that reared its head shortly after the new millennium began. While it may have seemed like Y2K was finally coming to fruition based on the amount of chaos that was caused, the actual cause of these blackouts was simply institutional problems with the power grid itself.

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Revealing Capcom’s Custom Silicon Security

April 3, 2017 by 52 Comments

Ask any security professional and they’ll tell you, when an attacker has hardware access it’s game over. You would think this easily applies to arcade games too — the very nature of placing the hardware in the wild means you’ve let all your secrets out. Capcom is the exception to this scenario. They developed their arcade boards to die with their secrets through a “suicide” system. All these decades later we’re beginning to get a clear look at the custom silicon that went into Capcom’s coin-op security.

Alas, this is a “part 1” article and like petulant children, we want all of our presents right now! But have patience, [Eduardo Cruz] over at ArcadeHacker is the storyteller you want to listen to on this topic. He is part of the team that figured out how to “de-suicide” the CP2 protections on old arcade games. We learned of that process last September when the guide was put out. [Eduardo] is now going through all the amazing things they learned while figuring out that process.

These machines — which had numerous titles like Super Street Fighter II and Marvel vs. Capcom — used battery-backed ram to store an encryption key. If someone tampered with the system the key would be lost and the code stored within undecipherable thanks to “two four-round Feistel ciphers with a 64-bit key”. The other scenario is that battery’s shelf life simply expires and the code is also lost. This was the real motivation behind the desuicide project.

An overview of the hardware shows that Capcom employed at least 11 types of custom silicon. As the board revisions became more eloquent, the number of chips dropped, but they continued to employ the trick of supplying each with battery power, hiding the actual location of the encryption key, and even the 68000 processor core itself. There is a 6-pin header that also suicides the boards; this has been a head-scratcher for those doing the reverse engineering. We assume it’s for an optional case-switch, a digital way to ensure you void the warranty for looking under the hood.

Thanks for walking us through this hardware [Eduardo], we can’t wait for the next installment in the series!

Recover Your Broken SD Card Selfies By Your Selfie

April 3, 2017 by 33 Comments

You may still have some luck getting those selfies off of your SD card, even if it will no longer mount on your computer. [HDD Recovery Services] shows us a process to directly access the NAND memory of a faulty micro SD card to recover those precious files you thought about backing up but never got around to.

On a Micro SD card you may have noticed there are two slightly longer pins than the rest. These are VSS and VCC pins. As long as they are not a dead short between the two the SD card controller isn’t completely trashed and we can go ahead and get into that little sucker. With a bit of know how — along with sandpaper, enameled wire, and a NAND reader — an image of your lost data can be recovered with a bit of patience and some good soldering skills.

Working your way down from a relatively high grit sand paper, slowly sand away the plastic on the underside of the SD card until you can clearly see the copper traces hidden away inside. Then solder your enameled wire onto the small solder pads to hook it up to a NAND reader and you should be able to read the data that was previously unreachable via conventional means. Of course you’re still going to need to make sense out of the NAND dump. That’s a topic for a different article.

If you ever find yourself in need of an SD card recovery tool you could always roll your own DIY NAND reader. We will likely give this process a try just to play round with the concept. Hopefully we’ll never need to do SD card recovery!

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Command Alexa With A Completely Mechanical Vintage Remote Control

April 2, 2017 by 10 Comments

Anyone with grandparents already knows that in ye olden days, televisions did not have remote control. Your parents probably still complain about how, as children, they were forced to physically walk over to the TV in order to switch between the three available channels. In these modern times of technological wonder, we have voice control, programmable touch screen remotes, and streaming services that will automatically play an entire season of the show you’re binge watching. However, before these, and before the ubiquitous infrared remote, television manufacturers were experimenting with ways to keep kids from having to run across the living room every time the channel needed to be changed.

Early remote controls were simply wired affairs — nothing too surprising there. But, it wasn’t long before methods of wireless control were being introduced. One early effort called the Flashmatic would shine light onto a photoelectric cell on the television set to control it. Of course, it might also be controlled by unintended light sources, and users had to have good aim to hit the sensor. These issues soon led to the introduction of the Zenith Space Command remote control, which used ultrasonic frequencies to control the TV.

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