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Reverse Engineering a Blu-ray Drive for Laser Graffiti


There’s a whole lot of interesting mechanics, optics, and electronics inside a Blu-ray drive, and [scanlime] a.k.a. [Micah Scott] thinks those bits can be reused for some interesting project. [Micah] is reverse engineering one of these drives, with the goal of turning it into a source of cheap, open source holograms and laser installations – something these devices were never meant to do. This means reverse engineering the 3 CPUs inside an external Blu-ray drive, making sense of the firmware, and making this drive do whatever [Micah] wants.

When the idea of reverse engineering a Blu-ray drive struck [Micah], she hopped on Amazon and found the most popular drive out there. It turns out, this is an excellent drive to reverse engineer – there are multiple firmware updates for this drive, an excellent source for the raw data that would be required to reverse engineer it.

[Micah]‘s first effort to reverse engineer the drive seems a little bit odd; she turned the firmware image into a black and white graphic. Figuring out exactly what’s happening in the firmware with that is a fool’s errand, but by looking at the pure black and pure white parts of the graphic, [Micah] was able guess where the bootloader was, and how the firmware image is segmented. In other parts of the code, [Micah] saw thing vertical lines she recognized as ARM code. In another section, thin horizontal black bands revealed code for an 8051. These lines are only a product of how each architecture accesses code, and really only something [Micah] recognizes from doing this a few times before.

The current state of the project is a backdoor that is able to upload new firmware to the drive. It’s in no way a complete project; only the memory for the ARM processor is running new code, and [Micah] still has no idea what’s going on inside some of the other chips. Still, it’s a start, and the beginning of an open source firmware for a Blu-ray drive.

While [Micah] want’s to use these Blu-ray drives for laser graffiti, there are a number of other slightly more useful reasons for the build. With a DVD drive, you can hold a red blood cell in suspension, or use the laser inside to make graphene. Video below.

Filed under: hardware


Nikes With Power Laces, Just in Time for Next Year


With the world’s first hoverboard being shown a few days ago, we’re on the verge of the fabulous world of tomorrow from Back to the Future. Hoverboards are cool, but there’s a wealth of other cool technology from the far-off year of 2015: Mr. Fusions, inflatable pizza, Dustbusters, and of course, Nikes with power laces. [Hunter] just built them, and with the right shoes, to boot.

[Hunter] is using the BttF-inspired Nike Air Mag shoes for this build, along with a few bits of electronics – an Arduino pro mini, a force sensing resistor, and a motor. The build began by carving out a notch in the back of the shoe for the electronics. A small bit of fishing line goes around the shoe, providing the power behind the power laces.

A force sensitive resistor under the heel of the insole tells the microcontroller when a foot is inside the shoe, and a rotary encoder on the motor shaft makes sure all the power lace cycles are the same. It’s not quite the same as the shoe seen on screen – the lower laces can’t be replicated and it’s certainly not as fast as the BttF shoes, but it does work, and as far as shoelaces are concerned, they work well.

Videos below.

Filed under: wearable hacks


Retrotechtacular: Fire Control Computers in Navy Ships

mainHere is a two-part Navy training film from 1953 that describes the inner workings of mechanical fire control computers. It covers seven mechanisms: shafts, gears, cams, differentials, component solvers, integrators, and multipliers, and does so in the well-executed fashion typical of the era.

Fire control systems depend on many factors that occur simultaneously, not the least of which are own ship’s speed and course, distance to a target, bearing, the target’s speed and course if not stationary, initial shell velocity, and wind speed and direction.

The mechanisms are introduced with a rack and pinion demonstration in two dimensions. Principally speaking, a shaft carries a value based on revolutions. From this, a system can be geared at different ratios.

Cams take this idea further, transferring a regular motion such as rotation to an irregular motion. They do so using a working surface as input and a follower as output. We are shown how cams change rotary motion to linear motion. While the simplest example is limited to a single revolution, additional revolutions can be obtained by extending the working surface. This is usually done with a ball in a groove.

The film moves on to describe these mechanisms in the context of fire control systems. It does an excellent job of explaining how several different cams take the rotary input of a ship’s speed and deliver it as linear motion to the follower for output to other systems. Most are aptly named based on the type of output delivered; a reciprocal cam’s output is computed as the reciprocal of the input, and a square cam’s output is the square of the input.

superelevationsA tangent cam’s input is an angle between 40 and 70, and the output is the tangent of that angle. A time of flight cam takes the range as input and gives the time of flight for projectiles. Perhaps the most complicated, the barrel cam takes the advance range and advance elevation of the target and uses them to compute the superelevation of a projectile. It effectively contains an infinite number of cams that each compute a different superelevation. Differentials are explained quite well through a visual breakdown of the bevel gear variety. In these, the end gear pair provides endless racks to the spider gear’s pinion.

Part two opens with component solvers, which solve vector problems for firing upon stationary targets. These provide continuous solutions by forming vector diagrams based on own ship’s speed and bearing to the target at any given point. The solver calculates the speed vector relative to line of sight with a groove cam, and uses two slotted racks to compute the range rate along the line of sight and the bearing rate perpendicular to the line of sight.

disc-type integratorDisc-type integrators are used for range keeping where the present range equals the algebraic sum of the initial range and the range change. The disc integrator continuously computes the range change and outputs it to a differential, which along with the initial range computes the present range. It does this using a time disc and the range rate output sent from the component solver. The mechanism operates like a variable gear with infinite ratios.

Finally, multipliers are used to multiply two continuously changing values, either or both of which may be positive or negative. This device is quite mesmerizing, if we may say so. The rack type described consists of two input racks at right angles to each other, an output rack, and a stationary pin that helps determine the zero point. Both input racks move along the scale and provide the product of the two inputs on the output rack.

Even though these systems were heavy, had a large footprint, and required a lot of power, there is much to be said for their elegance and reliability.

[Thank you to Barron for sending this in]

Retrotechtacular is a weekly column featuring hacks, technology, and kitsch from ages of yore. Help keep it fresh by sending in your ideas for future installments.

Filed under: Hackaday Columns, Retrotechtacular


8×8 LED Arrays Make for one Creepy Animated Pumpkin

Arduino Pumpkin

[Michal Janyst] wrote in to tell us about a little project he made for his nephew in preparation for Halloween – a jack-o-lantern with facial expressions.

Pumpkin Eyes uses two MAX7219 LED arrays, an Arduino nano, and a USB power supply. Yeah, it’s pretty simple — but after watching the video you’ll probably want to make one too. It’s just so cute! Or creepy. We can’t decide. He’s also thrown up the code on GitHub for those interested.

Of course, if you want a bit more of an advanced project you could make a Tetris jack-o-lantern, featuring a whopping 8×16 array of LEDs embedded directly into the pumpkin… or if you’re a Halloween purist and believe electronics have no place in a pumpkin, the least you could do is make your jack-o-lantern breath fire.

It’s pretty simple, but extremely effective — so if you’re looking for some last-minute decoration ideas, this might be it!

Filed under: Arduino Hacks, Holiday Hacks, led hacks


Apple looking to expand use of NFC in iPhone 6 and iPhone 6 Plus beyond Apple Pay

When Apple unveiled the iPhone 6 and iPhone 6 Plus, many were disappointed to find out that the built-in NFC technology could only be used for Apple Pay. Now, it looks like Apple is trying to make the NFC chip inside the iPhone 6 and 6 Plus more useful in day-to-day life by expanding its functionality to beyond payments.

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Star Gate LED Clock Has Plenty of Pizazz

Star Gate Clock

[David Hopkins] has finally finished off his Star Gate LED clock over on and it looks fantastic.

We originally featured his progress with the project in Hacklet 18 – Tick Tock, it’s Time for Clocks, and we’re happy to say it’s finally complete. The clock features 60 WS2812 LEDs to simulate the Star Gate’s chevrons — and to tell the time. Under the hood is an RTC, an Arduino Nano, an LDR and even an hourly ‘chime’. Did we mention it also automatically dims at night?

What we’re almost more impressed with is the build quality, which [David] doesn’t actually mention how he did it — regardless, it looks great! Stick around after the break to see a video of it in action, so you can really appreciate the clock’s capabilities.

We still think the Bacon Alarm Clock is one of our favorite ways of waking up though. Although if you’re in a hurry diffusing a bomb clock might be more effective…

Filed under: clock hacks


Meet J-Deite Quarter, the 4-Foot-Tall Transformer

Developers posing with the J-Deite Quarter

There’s just something about the idea of robots turning into everyday objects that fascinates us all. It seems Japan outdoes the world in that category, and the J-Deite project is no exception. J-Deite Quarter is the first transforming robot to come from the collaborative project between  [Kenji Ishida] of Brave Robotics, [Watur Yoshizaki] of Asratec Corp., and Tomy Co. Ltd. If Brave Robotics sounds familiar, that’s because this isn’t the first transforming robot [Kenji Ishida] has produced, nor the first featured on Hackaday.

The J-Deite Quarter weighs 77lbs (35kg) and can run for an hour on a single battery charge. It’s joints are powered by Futaba servos. It is controlled by the proprietary V-SIDO OS designed by [Watur Yoshizaki]. As a robot, it stands at 4.25 feet (1.3m). It walks at a rather slow speed of 0.6mph (1km/hr). It has several points of articulation; it can bend its arms and flex its fingers. In less than 30 seconds, the robot transforms into an equally long two-seat sports car with a maximum speed of just over 6mph (10km/hr). Overall, the J-Deite Quarter is no speed demon, but it is noteworthy for being functional in both forms.

The web site has a cute backstory featuring a green meteorite that allows the “real” J-Deiter to communicate with the developers trying to create a robot in its image. Along with the video, it resembles a marketing ploy for a toy, which could explain Tomy’s involvement. After all, Tomy, along with Hasbro, developed the original Transformers toy line. Unfortunately, the J-Deiter Quarter is just a prototype, with no plans for mass production at this time. Instead, the project’s focus is on making a bigger and better J-Deiter. There are plans for a J-Deiter Half (8-foot-tall) to be developed by 2016, with the final goal of creating a 16-foot-tall transforming robot by 2020.

Enjoy the video that shows what J-Deite Quarter is capable of (with added sound effects, of course) after the break. Now, if you’ll excuse me, I have a sudden hankering to watch some Transformers and Voltron cartoons.

[via SimpleBotics]

Filed under: robots hacks


Use a Cheap PIN Diode as a Geiger Counter


After the Fukushima nuclear power plant disaster, radiation measurement became newly relevant for a lot of people. Geiger-Müller tubes, previously a curiosity, became simultaneously important and scarce. (English-language version here) has complete instructions for making a Geiger counter without a Geiger-Müller tube. Instead, this counter uses a PIN photodiode and some carefully chosen operational amplifiers. The total cost of such a device is significantly cheaper than the alternative: under for the diode and around for the rest. And since the PIN photodiode in question is used in many other devices, it’s not a niche component like a Geiger tube is.

The secret sauce is in component selection and tuning. Opengeiger uses the BPW34 diode because it is relatively common and has a large surface area, but also because it has a very low capacitance when reverse-biased. The first-stage opamp choice is also fairly critical. Considering that an average gamma radiation event produces only around 10 nanoamps for about 50 microseconds, a lot of amplification (100,000x), low noise, and high bandwidth are a must.

If you want to get started with this project, you could first browse through the explanation (PDF) to get an overview of the project’s goals, read up on all the technical considerations (PDF) or just head straight for the DIY instructions for the “Stuttgarter Geigerle” (PDF, schematic is on the last page). All of the documentation is chock-full of relevant references and totally worth the read.

Filed under: how-to


Room Inc, creators of the app Room, are ‘debating legal action’ following the launch of Facebook’s Rooms

There are a lot of applications in any app store, but when it comes to Apple’s App Store, there are more than a lot. Unfortunately, sometimes a similar app finds its way out into the wild to something that already exists.

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Building A Magnetic Levitating Quadcopter

hover Three days ago on October 21, 2014 it was announced to the world the Back to the Future hoverboard was real. It’s a Kickstarter, of course, and it’s trending towards a Million dollar payday for the creator.  Surprisingly for a project with this much marketing genius, it’s a real, existing device and there’s even a patent. From the patent, we’re able to glean a few details of how this hoverboard/magnetic levitation device works, and in our post on the initial coverage, we said we’d be giving away some goodies to the first person who can clone this magnetic levitation device and put it up on

[jellmeister] just won the prize. It’s somewhat cheating, as he’s had his prototype hoverboard working in July, and demoed a more advanced ‘upside-down quadcopter’ device at the Brighton Mini Maker Faire in September. Good on ‘ya [jelly]. You’re getting a gift card for the hackaday store.

hoverLike the Kickstarter hoverboard, [jelly] is using an array of magnets rotating in a frame above a non-ferrous metal. For the initial test, eight neodymium magnets were arranged in a frame, suspended over 3/4″ aluminum plate, and spun up with a drill. With just this simple test, [jelly] was able to achieve 2kg of lift at 1cm and 1kg of lift at 1 inch of separation. This test also provided some valuable insight on what the magnets do to the aluminum or copper; the 3kg aluminum plate was nearly spinning, meaning if this device were to be used on small plates, counter-rotating pairs of magnetic lifters would need to be used.

The test rig then advanced to two pairs of rotors with standard hobby brushless motors, but stability was a problem; the magnetic rotors provided enough lift, but it would quickly fall over. To solve this problem, [jellmeister] took a standard quadcopter configuration, replaced the props with magnetic rotors, and successfully hovered it above a sheet of aluminum at the Brighton Maker Faire.

Since [jellmeister] has actually built one of these magnetically levitating hoverboards, he has a lot more data about how they work than an embargoed press release. The magnetic rotor hoverboard will work on aluminum as well as copper, but [jell] suspects the Kickstarter hoverboard may be operating right at the edge of its performance, necessitating the more efficient copper half pipe. The thickness of the non-ferrous plate also makes a difference, with better performance found using thicker plates. No, you bojo, hoverboards don’t work on salt water, even if you have pow-ah.

So there ‘ya go. That’s how you build a freakin’ hoverboard. [jellmeister]‘s design is a little crude and using a Halbach array for the magnetic rotors should improve efficiency. Using a 3D printed rotor design is a stroke of genius, and we’ll expect a few more quad-magnetic-levitating-things to hit the tip line in short order.

Demos of [jellmeister]‘s work below.

Oh. These things need a name. I humbly submit the term ‘Bojo’ to refer to any device that levitates though rotating magnets and eddy currents.

Filed under: misc hacks