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.

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CD Drive CNC Machine Steals Matt Groening’s Job, Says ‘Ha Ha’

DIY CNC Machines are fun to build. There are a lot of different designs all over the internet. Some are large and some small. Some are made from new material and others from recycled parts. [Leonardo’s] newest project is at the absolute far end of the small and recycled spectra. His CNC Machine is made from CD Drives and can draw a mean Nelson.

First, the CD Drives were disassembled to gain access to the carriages. These were then mounted to a quick and dirty wooden frame. Notice the Y Axis carriage is mounted with bolts and nuts that allow for leveling of the bed, not a bad idea. A Bic pen mounted to the Z axis carriage is responsible for the drawing duties.

[Leonardo] does something a little different for generating his g-code. First he takes a bitmap image and converts it to monochrome using MS Paint. The image is then imported into Cadsoft Eagle and using a modified import_bmp.ulp script. The bitmap is converted into what Eagle considers wire traces and then outputted as x and y coordinates for each wire complete with a command for lifting and lowering the pen.

A PC sends the move commands via USB, through a PL2303HX USB-Serial TTL Converter, to a PIC16F628A which, in turn, sends step and direction signals to the three Easy Driver stepper motor drivers. The stepper motor drivers are connected directly to the original CD Drive motors.

Check out the video after the break….

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Raspi Mini Laser Engraver

If you’ve got a lot of spare parts lying around, you may be able to cobble together your own laser engraver without too much trouble. We’ve already seen small engraver builds that use an Arduino, but [Jeremy] tipped us off to [Xiang Zhai’s] version, which provides an in-depth guide to building one with a Raspberry Pi.

[Xiang] began by opening up two spare DVD writeable drives, salvaging not only their laser diodes but the stepper motors and their accompanying hardware, as well as a handful of small magnets near each diode. To assemble the laser, he sourced an inexpensive laser diode module from eBay and used a vise to push the diode into the head of the housing. With the laser snugly in place and the appropriate connecting wires soldered on, [Xiang] whipped up a laser driver circuit, which the Raspi will later control. [Xiang] worked out the stepper motors’ configuration by following [Groover’s] engraver build-(we featured it a few years back)-attaching the plate that holds the material to be engraved onto one axis and the laser assembly to the other.

Check out [Xiang’s] project blog for details explaining the h-bridge circuits as well as the Python code for the Raspi. As always, if you’re attempting any build involving a laser, please use all necessary precautions! And if you need more information on using DVD burners for their diodes, check out this hack from earlier in the summer

Fail of the Week: Laser cutter that makes jagged edges

This Fail of the Week is really only a failure because of the standards to which [eLabz] holds himself. The rig pictured above is a laser cutter built out of DVD drive parts. It goes above and beyond most of the optical drive CNC projects we see around here — it actually makes cuts! But [eLabz] looks on it as a failure because the steps of the driver motors are visible as jagged edges in those cuts. We see this more as a pausing point in the development process before the next refinement is made.

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CNC Tic Tac Toe


This computer controlled physical Tic Tac Toe game is built from parts scavenged from common consumer goods. Specifically, the sled is made up of a combination of printer and DVD drive parts.

The build is delightful, and you can’t move on to the next feature until you watch it play a game in the clip after the break. The game board can move along two axes. It’s obvious from the image above that the printer ink cartridge sled has been reused to let the board move left and right. But the DVD lens sled hidden under the board lets it move forward and back. The piece of protoboard seen on the left is an IR reflectance scanner. The board moves systematically under this sensor. Whenever a black square (placed by the human player) is in play it prevents the IR beam from reflecting back. What you can’t see in this image is the yellow disc dispenser which is just out of the frame. It uses the DVD disc tray motor to place the computer’s pieces. We think this build is just begging to be turned into a Turing Machine demonstration.

If you liked this one we’re sure you’ll also appreciate CNC chess.

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Self-feeding pen printer

At first look we thought this was a plotter, but it’s really more of a dot matrix (or line matrix) printer. [Bruno] whipped this up using parts from a DVD optical drive. It is capable of moving the pen along the Z and X axes, and feeding the paper along the Y axis.

The video after the break shows the machine printing Megaman, an image perfectly suited to the low-resolution pixels this can put out. But even without the high-pixel counts you might get from a thermal printer, we just love the look of this one. And who doesn’t have an optical drive sitting around just waiting to be hacked? It looks like the one part you’re going to have to source is the stepper motor and geared feed wheel that moves the paper.

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