Archive for

November, 2010

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Nokia N900 and MeeGo packages

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Nokia N900 has been out for a while, and after N8 was released, everybody is now waiting for N9 which will be the first mobile to use the new MeeGo OS. However, MeeGo has already been officially ported to N900. From their set up instructions, this practically sold me on the phone already: “The ’scp’ and ’ssh’ tools should be available from within the device and you can transfer files in and out with them. You should also be able to run ‘yum install’ now, to install packages.“. That’s something users of all other phones cannot and probably will never be able to do.

I thought I’d have a look at which packages are available for the ARM7 architecture. The packages specific to ARM7 are not that surprising; just the basic stuff. However, looking at the repodata/patterns.xml file, it starts getting interesting. The package called meego-handset-devel-support has some very welcome dependencies, including: wget, openssh-server, rsync, screen, qt-devel, make, gcc, strace, valgrind, powertop.

All these can be found in the core section. However, the packages there are also available for other non-handset form factors, and might not be installable on a phone. We will just have to wait and see.

So although this looks very promising, I’m still holding on to my N80 for a while. Even after four years of use, it’s the best phone I’ve had. I’ll let others take care of the early adoption and testing.

Canon 60D

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I’m a bit late to the release party of Canon 60D, however, the solid reviews are starting to come in. That’s always a bit more interesting than press articles copy-pasting the release notes from Canon. Both Digital Photography Review and DigitalRev compares the new camera to Canon 7D. The former includes a comparison to 50D, while the later compares to 550D. In summary, it’s starting to get rather hard to compare and distinguish these bodies (unless you worry about minute details). The features are similar, the price points are 200 Euros or less in difference. So if you’re choosing from the high end, 7D is probably the way to go right now.

60D does video just like 7D, however this does still not interest me. Perhaps most interesting, is that unlike 50D, they’ve switched to SD cards (rather than CF which is still used in the high end models). It begs the question of whether CF will be completely replaced in next rounds of updates, within a couple of years.

A very minor feature I would welcome is the star rating. Reviewing the pictures on the camera, you can assign stars based on the quality (or whatever you choose for your own encoding scheme). That would certainly speed up publication of my images. Which reminds me, I have some pictures I need to shift through…

We are the robots

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I’ve been looking up a few robots lately. There are a lot of impressive kits out there, and many of them pass as toys for kids, even if the technology included would have impressed researches 10 to 15 years ago. First out, the Pololu 3pi line following wheeled robot. It’s based on an ATmega328 chip, and can be programmed like an Arudino. It has five reflectance sensors to detect a line beneath its front, and two motors to control speed and direction. An Arudino library makes programming easy. It’s $100 from SparkFun.

Next, the Lego MindStorms NXT 2.0, a Humanoid with an impressive selection of sensors, including ultrasonic distance sensor, light, and colour. It is controlled by a 8-bit Renesas H8/300 micro controller, and can communicate over Bluetooth or USB. The programming environment is tailored towards kids, using a GUI box interface. However, most other major programming languages can also be used through third party compilers. As usual with Lego kits, the parts can be used to build other models as well. Instructions for four different robots are included, and your imagination is the limit to what other things you can build. At $280 from Amazon, this seems like very good value for money.

Over at Active Robots, they have several toys and kits, including the walking Penguin Robot, based on the  BASIC Stamp 2px24 micro controller. Although a bit clunky, it looks fun. And at £150, it sounds like a good intermediate kit.

However, on the high end, Active Robots stock the Hitec Robotics ROBONOVA-I. This looks like the king of hobby robots, with 16 servos controlling arms and legs. It’s based on the ATMEL ATMega 128 micro controller (aka Arduino Mega), with several optional sensor like “gyros, acceleration sensors, speech synthesis modules and operational devices such as Bluetooth controllers and R/C transmitters and receivers”. It comes at a stiff price though; at almost £600, or 700 Euros, it’s for serious hobbyists, and not Johnny’s xmas present. Make sure you check out the robot football game, and other corny moves on its home page.

Also have a look at Active Robots other robot links; plenty of interesting material to browser through.

Finally, I thought it would be appropriate to round of with Krafwerk’s 1978 classic, “The Robots” (original title in German; “Die Roboter”).  “We are the robots!

Eitech Construction: Metal Building Toys

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While in Mexico recently, I picked up a fun construction set in metal, by Eitech. It has beams, nuts and bolts, wheels and other special parts to build one out of three models of industrial vehicles. Below is the kit I bought, but there is a wide range of other models, kits and experiments.

Since it was imported from Germany, I probably paid a high markup at 1100 pesos or 66 Euros. However, since I’ve yet to find the exact set, I cannot compare it. And more importantly, it was from a place which focused on robotic courses for young kids. While we were there, four kids were running around trying to program Lego Mindstorm robots to do line following. I’ll happily support a shop like that in what must have been its first few months of business.

Other great kits from Eitech includes a 60 cm long model of an old steam locomotive, and a 1.25 m tall model of the Eiffel Tower, including lights! The later I’ve found at PöppelShop for only 150 Euros. Probably have no choice but to get that one! Girders & Gears also have a good selection of the kits, as does Amazon.

More Small Fonts

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As an update to the MiniFonts post, here is an even smaller one from Adam Borowski. At 4 pixels wide and 6 high, it probably does not get much smaller.

WordPress for Android – Privacy Edition

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I like WordPress, and I like Android. However, I do not like the attitudes some of their developers have towards privacy. It seems to be “everything goes, as long as it benefits us”. In particular, the phone-home, and remote kill features, which many developers feel entitled to include, rub me the wrong way. Sorry, but it doesn’t fly on my device. I like your application, and want it to do its job well. Nothing more, nothing less.

Luckily, the WordPress for Android app is open sourced under GPL. It means I have right to access the source code, modify it, and distribute the modified version as long as I also reveal my code changes. So I did just that, fixing a few issues in the latest version (1.3.8) of WordPress for Android. The changes include:

  • Removing the location based permissions (fine and course grained).
  • Removing phone-home features to wordpress.com by which they collect a lot of identifying information, including the unique device ID.
  • Removing the EULA. The GPL is not an EULA! (More on that in a later post).

The patch is available here, and the APK installer binary built to the Android 2.2 platform (API level 8). However, I would encourage you to download and build the source code yourself. To do that, follow these steps:

  1. Download the source code for WordPress for Android:
    svn checkout http://android.svn.wordpress.org/trunk
  2. Download and apply the patch:
    cd trunk
    wget http://hblok.net/blog_resources/wordpress_android/wordpress_android_1_3_8_p_1_privacy.patch
    patch -p0 -i wordpress_android_1_3_8_p_1_privacy.patch
  3. Build the application in Eclipse. If you have not installed the Android SDK for Eclipse, here is the starting point of the download and install instructions.
  4. Search through the code and look for further privacy violations.

Small Fonts

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With small electronics and a LED matrix, you never know when a small font can come in handy. Here are some small pixel fonts and icons.

From Best Flash 2.2, there’s several freeware fonts. And over at Brainstorm and Raves, they spotted the Itsibitsi icons from MiniFonts. They also have several other tiny fonts, including Atom, with a cap height of only 6 pixels.

Online Parts Suppliers

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Nathan Seidle, founder of SparkFun, recently told the story of how his business started from his bedroom in 2004. Since then, there has popped up a lot of good suppliers of electronics and other maker parts online. Here’s a short list of some of them. Feel free to send me more links. Since almost all of these are US based, sites from Europe is especially welcome.

SparkFun – sparkfun.com

Very well equipped online electronics shop, with smooth ordering process. They stock basic components, soldering kits, robotics, Arduinos, and also produce several breakout boards and other items themselves. In Nate’s own words, “SparkFun makes technology more accessible.”

Furthermore, they have established healthy community, with comments and discussions on both the product pages and forums

Maker Shed – makershed.com

Grown out of the MAKE Magazine, Maker Shed have lots of different “projects in a box”, or kits; a little bit of everything. Including electronics, crafts, and chemistry sets.

Solarbotics – solarbotics.com

More components, kits, boards, and Arudinos. Focusing on robotic kists and solar cells.

The Electronic Goldmine – goldmine-elec.com

Electronic Goldmine “specialize in purchasing inventory lots directly from manufacturers and companies that build electronic equipment”. A very good selection of basic components at good prices, however with changing inventory from week to week.

ServoCity – servocity.com

Get your moving parts from ServoCity; including steppers, servos, DCs, and accessories. As well as other mechanical parts shaft couplers for your motors. Furthermore, they stock an extensive selection of batteries.

McMaster Carr – mcmaster.com

McMaster Carr has a wast selection of mechanical and  electrical parts, as well as utility hardware.

Conrad Electronics – conrad.com

Finally, the only non-US shop on the list for now; Conrad Electronics from Austria. They have web sites and shops in several European countries. They have a broad assortment of technical parts and kits, including consumer electronics, computer, hobby, lighting, and RC kits. Their selection of batteries is impressive.

Smallduino: Ardweeny

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Here’s probably the smallest fully functional Arudino out there: Ardweeny. At $10 from Maker Shed, you can’t go wrong. They market it as a bread board item, however I can’t see why you could not include it in a permanent project as well.

Scavenging: Printer

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More scavenging of old parts, this time from an Epson ink printer. Trust me, if you get your hands on a used printer, it’s best to just throw it away. It’s the dirtiest computer junk there is, with all of the inside covered in ink. The motors in there are probably not worth more than 10 Euros. However, if you’re reading this, it might already be too late.

Stepper EM-438

The stepper motor for the paper looks solid. However, there is no documentation what so ever on it. I just became yet another guy asking for a data sheet. I did find one video from somebody who have gotten it to run, though.

DC RS-455PA-15200

The second motor was a simple DC motor. The data sheet was easy to find. It’s from Mabuchi Motor, has a 12 – 42 V operating range, and draws 330 mA at maximum efficiency.

Fedora 14 Released

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Fedora 14 was released yesterday. You can find the release notes here. It seems that is mainly an incremental release, with few ground braking news. Most interesting is maybe the inclusion of a selection of the MeeGo applications; see section 2.1.4. Also, it seems GCC might include support for the AVR ATmega*U2 chips. Not sure what this will mean for Arudino development.

Gottchas include a change in the middle-button click behaviour. It will no longer be emulated by left+right click. See section 3.5.2. Here is what they say will fix that:

Middle mouse button emulation can be enabled by the addition of a xorg.conf snippet:

        Section "InputClass"
	  Identifier "middle button emulation class"
	  MatchIsPointer "on"
	  Option "Emulate3Buttons" "on"
	EndSection

More importantly, you can download your copy here. The various spins are worth having a look at. These are special variations on the distribution, focused on particular users, like education, research, entertainment, and so on. Of course, there is nothing stopping you from installing the same application regardless of which “spin” you start with.

Finally, to save some bandwidth, trees, and all that, look at the torrent files. They were a bit more hidden this time. However, they’re all still listed on torrent.fedoraproject.org

Panorama Robots

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It somehow seems inevitable; if you are into photography and electronics, you want to build a panorama robot. Coupled with very good software to stitch and render a panorama image, the results can be breathtaking even with little effort. For the stitching software, I recommend Hugin, the open source panorama stitcher. On a modern OS; just go yum / apt-get install hugin. For a good intro into setting up and shooting the single frames which goes into your panorama, see Robert. Cailliau’s article.

Once you’ve taken a few pictures, maybe five or even ten with a fairly wide angle lens, you realize that you can get even more detail if you use a zoom lens. Maybe 200 or 300mm. However, now you have to take hundreds of pictures to cover the same area in your finished panorama. This is were the robots come in.

The pocket camera on the turn table below is a very cheap solution; about 15 Euros. I have not found a specific product or manufacture name, though. It shows up in searches for “Panorama Drehteller“. Next to it is a more professional solution, the Gigapan Systems Epic 100 Panorama Robot. It can take a DSL, and pan both horizontally and vertically. You need both if you plan on using a 200mm lens.

So if you’re only into photography, and not DIY and soldering, those are maybe some of the solutions you’d go for. However, if you are able to build one yourself, what is stopping you? Nothing, it seems, judging by the number of home made panorama bots. Here is a Lego Mindstorms competition to build a pano bot with the winners from 2008. Here is a Jason Babcock’s second go at a panoramic turntable, using ULN2004A and BX-24 micro-controller.  And here is T. Emrich’s system which looks like a very solid setup, and clever control: His early work resulted in a horizontal rotation only solution. Later on, he built the GigaPanBot or Gigapixel Panorama Robot with complete freedom on both axis, seen in the picture below. Maybe most impressive, is how the whole system fits into his camera bag.

So what if you want to build your own. Well, nothing is stopping you, and there is plenty of parts to pick up to make a simple first system. Babcock’s first attempt was using a stepper motor from an old fax. Or you could buy a new stepper motors for less than 20 Euros.

To help you on your way, there’s the DollyShield, which I spotted on the Arduino Shield List. It includes control of two DC motors, shutter remote for the camera, joystick buttons and a LCD. “It is designed to provide an inexpensive and easy-to-use interface for two-axis motion control integrated with a camera.”

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