linux

653 Articles

Fonera-based Quadcopter Can Be Controlled From A Web Browser

August 1, 2011 by 11 Comments

fonera_html_controlled_quadcopter

[Tiakson] just wrapped up the construction of a quadcopter which piqued our interest due to the unexpected mix of hardware he used.

A good portion of the copter is made up of the essential bits we have come to expect from a quad rotor system. Instead of using an Xbee or hobby wireless controller however, [Tiakson] opted to use an old Fonera router running OpenWRT to control the system. He wrote special software that allows him to direct the quadcopter using an HTML 5 interface, adding a few kernel tweaks along the way that enabled him to emulate I2C ports over GPIO pins.

The Fonera takes in data from Wii nunchuck and Motion+ sensors, relaying commands to the on-board PIC 16F976 microcontroller. The PIC is used to manage the electronic speed controller modules using PWM, which the Fonera could not handle on its own.

This is a great use for a old router, and the cost is obviously far cheaper than buying off the shelf wireless control modules. We would love to hear how much extra weight the Fonera adds, as well as if there is any controller lag introduced by the web-based interface.

Continue reading to see a quick demo video of the quadcopter in action.

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Sleek, Disc-less GameCube Handheld

July 29, 2011 by 35 Comments

sd_card_gamecube_handheld

Console hacker [techknott] has a skill set that is quite possibly second to none. We do love [Ben Heck] and think that his portable consoles are beyond awesome, but you’ve got to check out this portable GameCube [techknott] put together.

While the construction details are pretty sparse, the video below shows off the bulk of the portable ‘Cube’s best features. Far smaller than his Flip-Top GameCube or Dreamcast portables we’ve featured in the past, his new handheld sports a wider screen and is completely disc-less. While the legality of booting backup copies of games from an SD card is something we won’t delve into, we do like the concept.

The console itself is probably only about one and a half times the width of a standard GameCube controller, and while it doesn’t sport an internal battery pack, we wouldn’t turn one down. Besides, who wants to play GameCube outside? With one of these in hand, we are more than happy to keep our pasty selves indoors, thank you very much.

The only complaint we have here is the lack of build details. [techknott’s] handheld consoles are pretty amazing – we just wish that we could see how the magic was made!

Be sure to check out the video below to see the console in action.

[Thanks, Dave]

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Hacking 14 Year Old Power PC Mac Back To Life

July 24, 2011 by 63 Comments

For a while now I have been battling a dying 2.6Ghz dual core computer, but due to laziness and budget I just let it ride. At first it would occasionally crash in games, then it got to where it would crash during routine activities. After a year of this it would nail 105 degrees C in like 20 seconds and that is where the drama starts!

I threw my 2ghz “electronics” computer into my main machine’s case and used that for a few months. It’s motherboard had suffered from every electrolytic capacitor on it being puffy, but it has worked fine for nearly 5 years. I was surprised by the sound of what ended up being 2 caps blowing off of the geforce 7600 video card. In shock and excitement I removed the blown caps, slapped her back in and got another 4 months out of it before 2 more capacitors blew and took out a voltage regulator (and who knows what else with it).

Only armed with the craptop, I was stuck in a pickle! Then a co-worker came up to me and said “hey man you want this mac I only want its zip drive”. Well of course, going bonkers without my avrgcc, datasheets, and calculators, I took on the 14 year old Apple Power Macintosh 9600/300 as my bench machine, and I will now show you how I turned it from a novelty relic to a daily useful machine after the break.

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Using A Router As A Linux-based PID Controller

July 21, 2011 by 23 Comments

espresso_machine_pid

[Nathan] had an small router kicking around and thought that he might as well put it to good use. He had always been interested in getting a better handle on his espresso machine, and figured that the router would be a perfect Linux-based PID controller.

He installed OpenWRT on the router, then disassembled it in order to get access to the router’s GPIO pins. He built a small PCB that allows him to get temperature info from the machine to the router using i2c. [Nathan] put together a PID package for OpenWRT, allowing him to control the machine over SSH, though he may build in a user-friendly web interface sometime in the future.

He says that most espresso machine PID controllers he has seen come in the form of big ugly boxes slapped on the side of the machine’s case, though we have to disagree with him on that point. Opinions aside, he is going for a minimalist design, and while he says that he is only about half way through the project, we think things are looking promising so far.

When everything is said and done, we hope to get a much closer look at all of his code, schematics, and more information on the router he used as well.

Adding Extra Buttons To A Cintiq Drawing Pad

July 14, 2011 by 7 Comments

wacom_cintiq_game_pad_addon

[David Revoy] recently picked up a brand new Cintiq 21UX, and while he liked the drawing pad overall, he was less than impressed with the tablet’s buttons. He says that most 2D linux apps require a good bit of keyboard interaction, and the built-in buttons just were not cutting it.

After seeing a fellow artist use a joypad to augment his tablet, [David] thought that he might be able to do something similar, but he wanted to add a lot more buttons. He dug out an old Logitech game pad that was collecting dust, and disassembled it, rearranging some buttons in the process. Once he was happy with the layout, he built a cardboard enclosure for the PCB and hooked it up to the Wacom via USB.

He spent a few minutes mapping buttons to key presses using Qjoypad, and was up and running with an additional 14 buttons in short order. He says that the extra buttons make his job a ton easier, and add a little bit of comfort to his long drawing sessions. We like the fact that it is a non-permanent fixture, and that he was able to repurpose an old game pad in the process.

Check out the video below for a quick demonstration of his drawing pad hack.

[via Adafruit blog]

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Reverse Engineering VxWorks (which Replaces Linux On Newer Routers)

July 8, 2011 by 25 Comments

The Linksys router seen about is a WRT54G version 1. It famously runs Linux and was the source of much hacking back in the heyday, leading to popular alternative firmware packages such as DD-WRT and Tomato. But the company went away from a Linux-based firmware starting with version 8 of the hardware. Now they are using a proprietary Real Time Operating System called VxWorks.

[Craig] recently put together a reverse engineering guide for WRT54Gv8 and newer routers. His approach is purely firmware based since he doesn’t actually own a router that runs VxWorks. A bit of poking around in the hex dump lets him identify different parts of the files, leading to an ELF header that really starts to unlock the secrets within. From there he carries out a rather lengthy process of accurately disassembling the code into something that makes sense. The tool of choice used for this is IDA Pro diassembler and debugger. We weren’t previously familiar with it, but having seen what it can do we’re quite impressed.

[Image via Wikimedia Commons]

How Canonical Automates Linux Package Compilation

June 12, 2011 by 25 Comments

pandaboard

What do you do when it’s time to port the most popular Linux distribution to a completely different architecture? Canonical employee [David Mandalla] works on their ARM development team and recently shared the answer to that question with his fellow Dallas Makerspace members.

Canonical needed a way to compile about 20,000+ packages for the ARM platform, however they did not want to cross-compile, which is quite time consuming. Instead, they opted to build a native solution that could handle the load while ensuring that all packages were compiled securely. To tackle this immense task, [David] and his team constructed a 4U server that runs 20 fully-independent ARM development platforms simultaneously.

The server is composed of 21 PandaBoards, small OMAP development boards featuring a dual-core ARM cortex processor with just about all the connectivity options you could possibly ask for. One board operates as the server head, keeping track of the other 20 modules. When someone requests server time to build a package, the main board checks for unused server, triggering a relay to reboot it before the server is automatically reimaged. Once the pristine, secure environment is ready to go, it’s handed off to the customer who requested it.

If you’re interested in learning more about the build process, [David] has put together a blog with additional details.

[Thanks Leland]