Accessing an SD card through a parallel port, just because

May 13, 2012 By Leave a Comment

[Vinod] sent in a very cool build he says is somewhat of a ‘mad project’: he mounted an MMC and SD card under Linux using the parallel port on his computer. Even though parallel ports are getting rarer these days, we absolutely love [Vinod]’s dedication and willingness to dig around the Linux kernel.

The hardware portion of the build is very simple – just an SD/MMC header and a few resistors wired up to a parallel port. The software side of the hack gets pretty interesting with [Vinod] building a kernel module, something we rarely see on Hackaday.

We’d have to agree with [Vinod]’s ‘mad project’ sentiment, if only because of the terrible throughput of [Vinod]’s adapter; it takes him more than a minute to transfer a 1.5 MB file onto the SD card – terribly slow, to put it mildly. Nevertheless, we’ve got to respect [Vinod] for pushing the limits of uselessness and still building something cool in the process.

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[Linus] wins the Millennium Technology Prize

April 20, 2012 By Leave a Comment

[Linus Torvalds] pumped out Linux roughly 20 years ago and has now won some pretty major recognition for his contributions. We’ve seen different flavors of Linux installed on virtually everything you can think of, even on a dead badger. This prize is being compared to the Nobel Peace Prize, since there isn’t a Nobel prize for technology(why not?).

While some might be wondering what the big deal about Linux is, consider this quote from the ZDnet article for a moment.

Is it deserved? Well, judge for yourself. Since Torvalds created Linux in 1991, it has become the world’s most ubiquitous operating system it powers the popular Android phones and eight out of 10 financial trades; it runs Amazon, Facebook, Google, Twitter and other major web networks. It is the dominant OS for supercomputers, supporting nine of 10 of these major systems, and is the preferable platform for cloud computing.

 

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Full Linux distro on a Nook color

April 17, 2012 By Leave a Comment

We should have included a footnote in the title. You can say that [Thomas Polasek] installed a full version of Arch Linux on his Nook Color, but there’s one caveat. It’s running on top of the Android kernel and his proof-of-concept uses a second computer to get it up and running. But there’s potential for that to change moving forward.

Unlike previous attempts to run a Linux distro on Android, this does away with using a VNC to show the desktop. [Thomas] is commandeering Android’s frame buffer so that it can be used by the X desktop without needing to set up display drivers. To start off he installed a ROM based on CM7. A couple of Android apps give him the functionality needed to get the Arch Linux distro running from the SD card. This is accomplished by tunneling into the tablet via SSH, and using the ‘chroot’ command to make it active. The hope is that this can somehow be automated by a script.

A female to female USB coupler was used to connect the keyboard and mouse to the Nook. It looks like LXDE would be useless without them; touch control is not yet implemented. Those shortcomings aside, everything seems to be running pretty fast in the video after the break.

[Read more…]

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IR helicopter controller hacked into a Linux game pad

April 14, 2012 By Leave a Comment

syma-linux-joystick

[Mike Kohn’s] Syma S107 helicopter wasn’t flying as well as it used to due to a broken gear, he figured he might as well find some use for the toy’s controller, since it was currently sitting around collecting dust. Having done a bunch of work with Syma IR protocols earlier this year, he decided it would be pretty easy to get the remote working as a game pad for his Linux desktop.

He patched an IR receiver into an MSP430 board, which decodes the incoming IR signals, sending them to his computer over a serial connection. [Mike] dug around in the Linux source for some good joystick driver code to borrow and found something that was close enough to work. After a bit of tweaking he loaded up his driver module and fired up Mame to give [Ms. Pacman] a try.

He says that the controller worked without much trouble, though as he discovered in previous projects, there are some quirks in the controller that make it somewhat less than convenient to use full time. Check out his site if you’re interested in taking a look at the code that he used to get things running.

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PS3 IR dongle tamed for use with a Linux box

April 10, 2012 By Leave a Comment

So a man walks into a Radio Shack and the clerk says “Why the long face?”. No, that’s not it. [Ms3fgx] walks into a Radio Shack and says “holy crap, that PS3 IR dongle is only two bucks”. He’s been looking for an IR remote receiver to use with a Linux machine and decided to bend this PS3 dongle to his will. It’s a lot less expensive that the parts to build the simplest IR receivers like this FTDI cable version, or a microcontroller based receiver.

He plugged it in and was delighted to find that it enumerates. The kernel has PlayStation 3 controller support built-in and has no problem picking up this device. When he uses ‘cat’ to display the incoming data all he gets is repetitive garbage. This is because the dongle only supports Sony remote control codes. But after a bit of universal remote setup, he’s got unique commands for each button. The last piece of the puzzle is to map the controller commands to keyboard keys. This is done with the QJoyPad package, but there are a myriad of ways to remap these buttons so go with what you know.

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Building the worst Linux PC ever

March 28, 2012 By Leave a Comment

Linux is generally considered the go-to OS for under powered computers. Wanting to challenge the preconceived notion that Linux requires ‘a computer made in the last 20 years,’ [Dmitry] built the worst Linux PC ever around a simple 8-bit microcontroller.

The ATMega1284p [Dmitry] used doesn’t have a lot to offer as far as RAM and storage goes; just 16 kilobytes of SRAM and a paltry 128 kilobytes of Flash storage. While this may be voluminous in the embedded world, it’s peanuts compared to the gigabytes of RAM and hard drive space on even a low-end netbook. To solve this problem, [Dmitry] threw an antique 30-pin RAM SIMM at the problem. It’s wired up directly to the microcontroller, as is the 1 Gigabyte SD card that serves as the PC’s hard drive.

Linux requires a 32-bit CPU and a memory management unit, something the puny microcontroller doesn’t have. For [Dmitry], the best course of action was emulating an ARM processor on an AVR. We’re not sure if we’re dealing with genius or madness here, but it did prove to be a valuable learning exercise in writing a modular ARM emulator.

How fast is it? [Dmitry] tells us it takes two hours to boot up to a bash prompt, and four more to load up Ubuntu and login. If you want a Megahertz rating, good luck; the effective clock speed is about 6.5 kilohertz. While the worst Linux PC ever won’t win any races, its simple construction puts it within the reach of even the klutziest of hardware builders; the entire device is just a microcontroller, RAM, SD card, a few resistors, and some wire.

If you’d like to build your own worst Linux PC, [Dmitry] has the firmware and disk image available to download. If you want to watch the time-lapse of this thing booting, check out the video after the break.

[Read more…]

Filed Under: linux hacks, Microcontrollers Tagged With: , , , ,
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