Teaching with robots

20 Oct

Teaching with robots

The last two years I've done a course in at Westerdals Oslo School of Art, Communication and Technology (formerly NITH). The school offers Bachelor & Master studies in informatics and I've been brought in as a teacher on the topic of Embedded Systems. The course (200 hrs total) is a volunteer topic for third year students that covers all the basic use of Microcontrollers as well as some Embedded Linux.

It's been a great experience and I get to play santa - giving students a customised version of this kit. 4Tronix have been very helpful in making me a super Arduino-kit that covers the entire curriculum at a price that the school can live with. The only part of the curriculum that isn't covered by this kit is robotics and motor control. This year I think I've found a near perfect solution that I though I'd share with other educators.

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Making a custom 3D printer controller

20 Aug

Making a custom 3D printer controller

While working on my new printer, I realised how ugly most reprap controllers are. All those I've seen use large SD cards & bulky oldskool LCD's with really poor contrast and viewing angles. Why not use Micro SD & an OLED screen?

You can actually build your own custom controller using any combination of screen, SD reader and encoder, but I couldn't find a good description of how to do it, so here it is. Setting it up with the Marlin firmware can however be a daunting task, so this article aims to document how I went about doing it.

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Why I’ll never use Windows Phone again

04 Aug

Why I’ll never use Windows Phone again

It's been a while since I posted a good rant. Here's one that's been brewing for some time. I refuse to belive that ANY Microsoft employes that ever had an iPhone or Android, actually tried to use Windows Phone for a full year. I have and I can tell you - it's utter bullshit. I don't doubt that a lot of talented people have worked hard to make it happen, but without someone capable of telling what is good and bad, you cannot succeed. The whole OS reeks of a lack of interest and use.

I gave it a full year as I figured they'd get som time to fix the major bugs. Despite three fixes delivered over the air, they have not solved anything that could help me like the platform. They have however added a menu with "Extra settings" that I'll never use.

Here's my 6 biggest annoyances:

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Summertime

07 Jul

Summertime

I really love those squeezed-in weeks of work in between family holidays. It's a rare time to catch up on thing like blogging, reading & updating a few personal projects. I just finished reading The Martian by Andy Weir that I got recommended from @hpeikemo. It's a really thrilling book that I'm sure we'll see as a hollywood movie soon. The story is kind of a "Robinson Crusoe meets McGyver on Mars". After reading it, I gave it to my son who completed it in just two and a half day. Great summer read!

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What platform next?

20 Feb

What platform next?

In 2013, Adobe completely dropped the ball on the Flash Player and AIR. All further development has been moved to India. This normally means that the software has been put in what is referred to as "Maintenance mode". Any serious bugs will be fixed, but don't expect much in terms of new features. If you take a look at the Release Notes for AIR 4.0, you'll see what I mean.

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Apple is not currently accepting applications built with AIR 3.9

03 Feb

Apple is not currently accepting applications built with AIR 3.9

From the 1st of February, you'll get the following error message when trying to submit your Adobe AIR based app to Apple's App Store:

    Apple's web service operation was not successful
    Unable to authenticate the package: somenumber.itmsp
    ERROR ITMS-9000: "This bundle is invalid. Apple is not currently accepting applications built with this version of the SDK." at SoftwareAssets/SoftwareAsset (MZItmspSoftwareAssetPackage)

From February, you'll have to build your AIR apps using the iOS 7 SDK (comes with XCode 5). In other words - if you are using Flash Builder or the Open Source Flex SDK to make iOS apps, you'll need to upgrade a bit. Adobe added support for this in the 4.0 Beta version of the AIR SDK that is now available on Adobe Labs. I do not know how this affects Windows users, but for Mac users you just download Xcode 5.x and use this instead of XCode 4.x. Next you download the AIR 4.0 Beta SDK and install it. Instructions for how to install/upgrade your AIR SDK can be found here.

With the beta and XCode installed, all you have to do is to up the version number to 4.0 in your App XML and maybe update the path to the new iOS simulator for testing.

Note: this only applies to new submissions. All apps that are already approved are still good.

 

Error occurred while installing the application: Invalid specified

28 Dec

Whenever you get this error, you need to check exactly what devices are connected to the computer. I had the problem that every time one of my colleagues came to the office, Flash Builder would all of a sudden not debug the AIR apps that I built using Flash Builder. The problem affects all ADT-based tools so this might be useful also if you're using Adobe Flash Professional or other tools (like xcode, java) or more to author your Android or iOS apps.

The fix is simple. Open a terminal window and type the following:

/Applications/YourApplicationName/eclipse/plugins/com.adobe.flash.compiler_4.7.0.349722/AIRSDK/bin/adt -devices -platform ios

The path to ADT will vary based on your machine, but if you're using some kind of Flash SDK, it'll be in a subfolder like the above. This command will show a list of the devices currently seen by the ADT and in my case, the phone belonging to my coworker showed up. His device wasn't physically connected to my machine, but since ADT supports debugging via wifi, it can still be used by the tool. For some reason, Adobe's tools will ignore the request to debug via cable and instead tries to connect to the Wifi device.

Pressure sensitive floor

28 May

Pressure sensitive floor

I just came back from the most challenging physical computing project I've ever done. It's a 13 by 8 meter labyrinth where you walk in the dark and get a sensory experience based on more than 300 sensors. The main challenge was actually how much time it took to execute it, but it was such a fun project that I didn't really mind. You can now try it out yourself at Energisenteret in the theme park Hunderfossen (Troll-themed!) near Lillehammer, Norway. I don't know for sure, but I think this is the worlds first "pressure sensitive floor"?

I've worked on several projects with the company SixSides and about a year ago, they asked me if I could build a floor that reacted to the people walking on it. The basic idea was to play back sounds of walking on other surfaces than you really were. Of course I said yes to the challenge!

Read the rest in the hardware blog...

 

VerifyError: Error #1102: Illegal default value for type int

07 May

Stubled across an AS3 compiler bug that I've seen before, but couldn't find a good explanation via Google for. If you get the above error, make sure you don't initialize an "int" to "null". Changing it from:

public function Quad( w:Number, h:Number, color:int = null )

to:

public function Quad( w:Number, h:Number, color:int = undefined )

will remove this stupid compiler error...

Unexplainable errors in Flash Builder 4.7

11 Feb

For reference: if you have unexplainable errors in Flash Builder 4.7 (and other versions) make sure you turn off "Marc Occurences" in the IDE. Turning this feature off holds the key to removing errors such as:

"com.google.common.collect.ComputationException: java.lang.NullPointerException" and several more.