Every year, new models of laptops arrive on the shelves. This means that old laptops usually end up in landfills, which isn’t exactly ideal. If you don’t want to waste an old or obsolete laptop, though, there’s a way to reuse at least the screen out of one. Simply grab an FPGA off the shelf and get to work.
[Martin] shows us all how to perform this feat on our own, and goes into great detail about how all of the electronics involved work. Once everything was disassembled and the FPGA was wired up, it took him a substantial amount of time just to turn the display on. From there it was all downhill: [Martin] can now get any pattern to show up on the screen, within reason. The only limit to his display now seems to be the lack of external RAM. He currently uses the setup to drive an impressive-looking clock.
This is a big step from days passed where it was next to impossible to repurpose a laptop screen. Eventually someone discovered a way to drive these displays, and now there are cheap electronics from China that can usually get a screen like this running. It’s impressive to see it done from scratch, though, and the amount of detail in the videos are a great way to understand how everything is working.
The handheld screw driver is a wonderful tool. We’re often tempted to reach for its beefier replacement, the power drill/driver. But the manually operated screw driver has an extremely direct feedback mechanism; the only person to blame when the screw strips or is over-torqued is you. This is a near-perfect tool and when you pull the right screwdriver from the stone you will truly be the ruler of the fastener universe.
A Bit of Screw Driver History:
In order to buy a good set of screw drivers, it is important to understand the pros and cons of the geometry behind it. With a bit of understanding, it’s possible to look at a screw driver and tell if it was built to turn screws or if it was built to sell cheap.
Screw heads were initially all slotted. This isn’t 100 percent historically accurate, but when it comes to understanding why the set at the big box store contains the drivers it does, it helps. (There were a lot of square headed screws back in the day, we still use them, but not as much.)
Flat head screws could be made with a slitting saw, hack saw, or file. The flat-head screw, at the time, was the cheapest to make and had pretty good torque transfer capabilities. It also needed hand alignment, a careful operator, and would almost certainly strip out and destroy itself when used with a power tool.
These shortcomings along with the arrival of the industrial age brought along many inventions from necessity, the most popular being the Phillips screw head. There were a lot of simultaneous invention going on, and it’s not clear who the first to invent was, or who stole what from who. However, the Philips screw let people on assembly lines turn a screw by hand or with a power tool and succeed most of the time. It had some huge downsides, for example, it would cam out really easily. This was not an original design intent, but the Phillips company said, “to hell with it!” and marketed it as a feature to prevent over-torquing anyway.
The traditional flathead and the Phillips won over pretty much everyone everywhere. Globally, there were some variations on the concept. For example, the Japanese use JST standard or Posidriv screws instead of Philips. These do not cam out and let the user destroy a screw if they desire. Which might show a cultural difference in thinking. That aside, it means that most of the screws intended for a user to turn with a screw driver are going to be flat-headed or Philips regardless of how awful flat headed screws or Philips screws are.
[Oscar] wonders why hobby projects ignore all the powerful brushless motors available for far less than the equivalent stepper motors, especially with advanced techniques available to overcome their deficiencies. He decided it must be because there is simply not a good, cheap, open source motor controller out there to drive them precisely. So, he made one.
Stepper motors are good for what they do, open-loop positioning along a grid, but as far as industrial motors go they’re really not the best technology available. Steppers win on the cost curve for being uncomplicated to manufacture and easy to control, but when it comes to higher-end automation it’s servo control all the way. The motors are more powerful and the closed-loop control can be more precise, but they require more control logic. [Oscar]’s board is designed to fill in this gap and take full advantage of this motor control technology.
The board can do some pretty impressive things for something with a price goal under $50 US dollars. It supports two motors at 24 volts with up to 150 amps peak current. It can take an encoder input for full closed loop control. It supports battery regeneration for braking. You can even augment a more modest power supply to allow for the occasional 1 KW peak movement with the addition of a lithium battery. You can see the board showing off some of its features in the video after the break.
Manufacturers of 3D printers have a lot to do before they catch up with makers of the cheapest 2D, paper-based printers. If you’ve ever taken an inkjet apart, you’ll most likely find some sort of closed-loop control on at least one of the axes. The 2D printer will tell you when you’re out of ink, when a 3D printer will go merrily along, printing in air without filament. File formats? Everything is Gcode on a 3D printer, and there are dozens, if not hundreds of page description languages for 2D printers.
The solution to some of these problems are drivers – software for a 3D printer that slowly consumes the slicing of an object, printer settings, and placing an object on the bed. It’s coming, and the people who are responsible for making your 2D printer work with your computer are busy at work messing up the toolchain for your 3D printer.
The latest version of CUPS (C Unix Printing System) adds support for 3D printers. This addition is based on meetings, white papers, and discussions in the Printer Working Group (PWG). There has already been a lot of talk about what is wrong with the current state of 3D printer toolchains, what can be improved, and what should be completely ignored. Let’s take a look at what all of this has accomplished.
If you haven’t been paying attention, FTDI, makers of one of the most popular USB to UART chips out there, really screwed up last October. They released a driver to Microsoft that would brick unauthorized clones of their chip by setting the USB PID pair to zero. This renders the chip unusable by any computer. That Windows driver has been fixed by now, but there’s probably still a good number of bricked FTDI chips out there. [Tony G] figured out how to fix it, and it only requires a few lines in the console of a proper OS.
The bricking Windows driver worked by setting the USB PID on fake chips to 0000. Luckily, there are ways to reprogram these chips. [Mark Lord] released a set of tools that will reset the USB PID. This unbricks the chip, fixing whatever device it’s attached to. It’s also a great reminder to either update or roll back your Windows drivers.
The old gen 1 Kinect has seen a fair bit of use in the field of making 3D scans out of real world scenes. Now that Xbox 360 Kinects are winding up at yard sales and your local Goodwill, you might even have a chance to pick one up for pocket change. Until now, though, scanning objects in 3D has only been practical in a studio or workshop setting; for a mobile, portable scanner, you’d need to lug around a computer, a power supply, and it’s not really something you can fit in a back pack.
Of course, a portabalized Kinect 3D scanner has been done before, but that was with an absurdly expensive Gumstix board. With a Raspi or BeagleBone Black, this driver has the beginnings of a very cheap 3D scanner that would be much more useful than the current commercial or DIY desktop scanners.
The omniwheels work in this tripod orientation because they include rollers which turn perpendicular to the wheel’s axis. This avoids the differential issue cause by fixed-position wheels. When the three motors are driven correctly, as shown in the video below, this design makes for the most maneuverable of wheeled robots.
An aluminum plate serves as the chassis. [Malte] milled the plate, cutting out slots for the motor with threaded holes to receive the mounting screws. A few stand-offs hold the hunk of protoboard which makes up the electronic side of the build. The large DIP chip is an ATmega168. It drives the motors via the trio of red stepper motor driver boards which he picked up on eBay.
So far the vehicle is tethered, using a knock-off of a SixAxis style controller. But as we said before, driving the motors correctly is the hard part and he’s definitely solved that problem.