When you want to read what is being said on a television program, movie, or video you turn on the captions. Looking under the hood to see how this text is delivered is a fascinating story that stared with a technology called Closed Captions, and extended into another called Subtitles (which is arguably the older technology).
I covered the difference between the two, and their backstory, in my previous article on the analog era of closed captions. Today I want to jump into another fascinating chapter of the story: what happened to closed captions as the digital age took over? From peculiar implementations on disc media to esoteric decoding hardware and a baffling quirk of HDMI, it’s a fantastic story.
There were some great questions in the comments section from last time, hopefully I have answered most of these here. Let’s start with some of the off-label uses of closed captioning and Vertical Blanking Interval (VBI) data.
Continue reading “History Of Closed Captions: Entering The Digital Era”
We’ve all likely seen the amazing images possible with a scanning electron microscope. An SEM can yield remarkably detailed 3D images of the tiniest structures, and they can be invaluable tools for research. But blasting high-energy cathode rays onto metal-coated samples in the vacuum chamber of a bulky and expensive instrument isn’t the only way to make useful images, as this home-brew laser scanning microscope demonstrates.
This one comes to us by way of [GaudiLabs], a Swiss outfit devoted to open-source lab equipment that enables citizen science; we saw their pocket-sized thermal cycler for PCR a while back. The basic scheme here is known as confocal laser scanning fluorescence microscopy, where a laser at one wavelength excites fluorescent tags bound to structures in a sample. Light emitted by the tags is collected, and a 3D image is built up from multiple scans of the sample at different focal planes.
Like many DIY projects, this microscope is built from old DVD parts, specifically the pickup heads. The precision optics in these commonly available assemblies, which are good enough to read pits as small as 150 nm on a Blu-Ray DVD, are well-suited for resolving similarly sized microstructures. One DVD pickup is used to scan the laser in the X-axis, while the other head is modified to carry the sample and move it in the Y-axis. The pickup head coils and laser are driven by an Arduino carried on a custom PCB along with the DVD heads. Complete build files are posted on GitHub for anyone interested in recreating this work.
We love tips like this that dig back a bit and find things we missed the first go-around. And the equipment [GaudiLabs] lists really has potential for the budding biohacker, which we also like.
Thanks for the tip on this one, [Bill].
For many generations, home consoles have featured copy protection. Aiming to stop users from playing pirated games as well as running homebrew code, hackers often race to find vulnerabilities shortly after each new launch. Of course, finding workarounds can sometimes be more of a marathon than a sprint. [CTurt]’s new hack may come many years after the PlayStation 2 has since faded from store shelves, but remains impressive nonetheless.
The goal was to find a way to run unsigned code on the PlayStation 2 without using any complex external hardware. Hacked memory cards, network interfaces, and other trickery were ruled out. Instead, sights were set on using the only other way in to the console – through the DVD drive.
The only burnable media the PS2 DVD drive will normally read comes in the form of DVD video discs. Thus, [CTurt]’s search began in the code of the on-board DVD player software. After finding potential overflow targets in the code, it was possible to exploit these to run unsigned code.
It’s not yet a fully-polished piece of code, and [CTurt] notes that additional work may be required to get the exploit working on all firmware versions of the console. Regardless, it’s as simple a hack as you could possibly ask for – burn the disc, and away you go! It reminds us fondly of the Sega Saturn hack exploiting the MJPEG interface. Video after the break. Continue reading “FreeDVDBoot Opens Up The PlayStation 2 Like Never Before”
The influx of cheap laser cutters from China has been a boon to the maker movement, if at the cost of a lot of tinkering to just get the thing to work. So some people just prefer to roll their own, figuring that starting from scratch means you get exactly what you want. And apparently what [Mike Rankin] wanted was a really, really small laser cutter.
The ESP32 Burninator, as [Mike] lovingly calls his creation, is small enough to be in danger of being misplaced accidentally. The stage relies on tiny stepper-actuated linear drives, available on the cheap from AliExpress. The entire mechanical structure is two PCBs — a vertical piece that holds the ESP32, an OLED display, the X-axis motor, and the driver for the laser, which comes from an old DVD burner; a smaller bottom board holds the Y-axis and the stage. “Stage” is actually a rather grand term for the postage-stamp-sized working area of this cutter, but the video below shows that it does indeed cut black paper.
The cuts are a bit wonky, but this is surely to be expected given the running gear, and we like it regardless. It sort of reminds us of that resin 3D-printer small enough to fit in a Christmas ornament that [Sean Hodgins] did a while back. We’d suggest not trying to hang this on a tree, though.
Continue reading “Tiny Laser Cutter Puts Micro Steppers To Work”
We’ve seen a number of DVD- and CDROM-based small CNC machines here, but few are as simply beautiful as this one by [julioberaldi] over on Instructables (translated from Portuguese here).
We’ll cut to the chase; it’s the frame. Cut from steel sheet scraps with a hacksaw, and welded or soldered together with “bar solder”. It looks like a lot of sanding, painting, and polishing went on. The result is something we’d be proud to have on our desk.
For now, it simply draws with a pen. But watch the video, embedded below, and you’ll see that it runs exceptionally smoothly. If we’re reading the Instructable right, the next step is to turn this into a CNC cutter. We can’t wait to see where the project goes from here.
Continue reading “A Truly Classy Metal-Framed Mini CNC”
The next great advancement in homebrew electronics is an easy way to turn copper clad board into functional circuit boards. This has been done since the 60s with etch resist pens, sheets of etch resist rub-on transfers, the ever-popular photocopy and clothes iron, and now with small CNC mills. It’s still a messy, slow, and expensive process. [johnowhitaker] and [esot.eric] are trying to solve the latter of these problems with a mini PCB printer made out of DVD drives.
Playing around with the guts of a DVD drive is something [john] and [eric] have been doing for a while now, and for good reason. There’s a lot of interesting tech in DVD drives, with motors, steppers, and gears able to make very, very accurate and precise movements. Most PCBs aren’t very big, either, so a laser cutter that can only traverse an area a few inches square isn’t that much of a downside in this case.
With a small diode laser mounted to a CNC gantry constructed out of DVD drives, the process of making a PCB is actually pretty simple. First, a slurry of laser printer toner and alcohol is applied to the board. Next, the laser on this PCB printer lases over the traces and copper fills, melting the toner. The board is removed, the excess toner wiped off, and the unwanted copper is melted away. Simple, even if it is a little messy.
Of course this method cannot do plated traces like your favorite Internet-based board house, but this does have a few advantages over any other traditional homebrew method. It’s cheap, since CD and DVD drive mechanisms are pretty much standardized between manufacturers. It’s also easy to add soldermask printing to this build, given that soldermasks can be cured with light. It’s a very cool build, and one that would find a home in thousands of garages and hackerspaces around the world.
Robotics kits are a great way to get folks , young and old, interested in hacking and learning the basics. Quite often, the cost puts them off – it’s no fun if you mess things up while learning how to put an expensive kit together. Many kits are too polished and that leads to beginners feeling that they’ll never be able to build something complex like a robot. The Shonkbot is what the team at Bristol Hackspace came up with for a robot that is obvious in its working and encouragingly easy to build, even for kids (with supervision). To that effect, they completely avoided custom PCBs and laser cut bits. The Shonkbot is built from easily available parts and some commonly available materials. They aimed to build it for £5, but managed £15. With proper planning and time, they guess it can be brought down to £10.
The Shonkbot is built using an Arduino Nano, two stepper motors with their drivers, a 3xAA battery box and some bits and bobs. Assembly takes about an hour for a 10-year-old and then they can reprogram it in another workshop or at home. The “frame” of the Shonkbot is an old CD-ROM or DVD disk. Everything is hot glued to this frame. At the centre of the disk, a Sharpie is inserted and the Arduino code then allows the robot to draw on paper. Upgrades include adding an IR LED, a photo transistor and a buzzer to allow the Shonkbot to detect objects, or communicate with other Shonkbots. Build instructions are detailed in this document, and the code is available from the Github repository. Here is a photo album from their first build workshop which was held recently.
Thanks to [Matthew Venn] from the Bristol Hackspace for sending in this tip. Check the robot in action in the video below.
Continue reading “Cheap, Easy To Build Robot For Beginners”