First post #iste12

I've safely arrived in San Diego for the ISTE 2012 conference. Air Canada was great, I watched a few movies on the in-flight system and apart from an engine not starting initially on one plane, things went smoothly.

I've checked into a hotel across from the convention center, and already had a swim in the pool. I'm looking forward to some preconference activities, and the start of the official conference on Sunday.

Do They Need a Computer?

(This is a cross-post from the EIPS guest blog at eips.staffconnect.ca.)

I’ve often been asked if a mobile device, such as a tablet (usually iPad) or smartphone, is enough for a student to bring to school rather than a laptop. My usual response is that they are good alternative devices for someone who already has access to a traditional computer. There will always be things that you can only do, or can do more efficiently, on a computer.

A while ago I talked to a student who had written a 2,000 word essay on his smartphone. I’ve seen animated short films produced entirely on an iPad. In a meeting full of adults, most of them will be using a tablet or a phone. You can accomplish a surprising number of things using only a web browser and camera, and perhaps some platform-specific apps.

That being said, a student who has only a mobile device will be at a disadvantage. Particularly in secondary grades, there will be things that they can’t do on their handheld. Ideally students should be able to choose what they want to use for a particular activity. In my house there are many kinds of devices; family members can pick up, or sit down at, whichever is available and suited to the task.

In 2010 Steve Jobs was quoted as saying that in the future, “[personal computers] are going to be like trucks, less people will need them.” My brother-in-law has a truck that I can borrow when I need to move heavy stuff… do you think we should get to the point where students with handheld devices can just borrow school computers for their heavier tasks?

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David Hay is currently working with the Alberta Initiative for School Improvement (AISI) project in EIPS and can be found online at misterhay.com. If he wasn’t in education, David says he would be home with his kids!

bringing technology to the ISTE conference

I've been thinking a fair amount about technology that I'll bring to the ISTE conference. Since I'm flying there and I will be walking a lot, size and weight are concerns. At this point I'm thinking an iPad, maybe my Android phone (without a SIM card in it, since I won't have an international plan), and a Samsung Series 5 Chromebook. I'm also probably going to bring a waterproof point-and-shoot camera.

The two main devices (iPad and Chromebook) have great battery life, and should allow me to do everything I need to do down there. The phone will allow me to try out Android apps that I come across, and act as a Skype/Hangout device when I'm out without the other two.

What electronics do you usually travel with?

blogging from the ISTE conference

I've decided to post at least daily from June 24th to 27th about what I see at the ISTE 2012 Conference. Stay tuned here for updates.

ISTE is the International Society for Technology in Education.

assessment and no zeros

Following an Edmonton teacher's suspension for "ignoring his principal’s repeated directions to follow the school’s no-zero grading practice", there has been a lot of discussion about assessment. I just wanted to link here to a couple of blogs that I think best express opinions from educators who are using assessment properly.


Zero-Knowledge Proofs by John Scammell
for the love of learning by Joe Bower
Teaching on Purpose by Cherra-Lynn Olthof

For the most part I agree with them, so it's easier to link to them than to re-invent the wheel.

Print a 3D Key Fob from an Image or Logo

I've also published this as an Instructable and uploaded the related files to Thingiverse.

Let's say, hypothetically, that you need to design a 3D printable key fob for an event this weekend. First you check Instructables and Thingiverse to see if anyone has done it already. Unfortunately no one has, so you come back and read this Instructable. Don't worry, though, it's not that difficult. This basically involves converting a black and white image to vector format and extruding it into a 3D shape.

Through the process of modelling a key fob, students will be able to explore a practical application of geometry and algebra.

Instructors can also take this opportunity to remind students about the importance of respecting intellectual property, trademarks, and copyright.

Software and Hardware Requirements

For converting the image to a vector graphic, we'll use Inkscape (with the Better DXF plugin or R12 plugin).

To extrude the vector graphic into 3D and add the key ring attachment we'll use OpenSCAD.

Preparing the file for printing will involve ReplicatorG or similar software.

Making a physical model will require a 3D Printer (e.g. MakerBot) or a service such as Shapeways.

Setting up Inkscape and "Better DXF Output"

Download and install Inkscape from inkscape.org. If you're running Windows you can use the installable or portable (no install required) version.

To install the "Better DXF Output" extension, download the file better_dxf_output.zip. Extract the three files and put them in "C:\Program Files\Inkscape\share\extensions" (if you installed the Windows version) or "...\InkscapePortable\App\Inkscape\share\extensions" (if you're using the Windows portable version) or "usr/share/inkscape/extensions" (if you installed the Linux version).

Start up Inkscape and you should now be able to save drawings as "Better DXF Output" files. We need to use this extension because OpenSCAD requires R12 DXF files, and Inkscape 0.48 and newer exports R13 DXF files.

Converting the Image to a Vector Graphic

This is probably the most difficult part, but it shouldn't be too hard. We're going to import the logo into Inkscape, trace it, clean it up if necessary, and export it as a DXF file for the next step. If you already have a (R12) DXF file of your logo, you can skip this step.

1. Under the File menu chose Import... and select your logo file. Hopefully it's a single colour (e.g. black and white) bitmap.

2. Click on your logo, then under the Path menu choose Trace Bitmap...

3. On the dialogue box that comes up, click OK and then close it. If all goes well you should now have a path object above your original bitmap.

4. Move the path object out of the way, and delete the original bitmap. Move the path object back to the bottom left (0, 0).

5. If there are parts of the image that you don't want, under the Path menu choose Break Apartand delete the unwanted parts

6. Select everything that remains and under the Path menu choose Combine.

7. Resize the path object to the size you'd like your key fob to be by typing the size in the W (width) or H (height) box. Make sure your click the lock button first to make sure you don't change the aspect ratio of your logo.

8. Under the File menu choose Save As... then choose Better DXF Output (*.DXF) from the dropdown menu. Name your file logo.DXF and remember when you save it so that you can use it for the next step.

Creating a 3D Model

Now that you have a DXF file of your logo, we need to make it 3D.

Go to OpenSCAD.org to download the program for Linux, OS X, or Windows and install (or unzip and run the portable version).

Run OpenSCAD and paste in the following code (or download the attached logo.scad file).

width = 50; // the x size of the logo
length = 40.572; // the y size of the logo
logodepth = 2; // how far in the z direction you want the logo extruded
backdepth = 1; // thinckness of the back of the key fob
padding = 3; // how far from the edge you want the logo
holewidth = 10; // the size of the ring attachment on the top

color("green") translate(v = [0, 0, backdepth]) linear_extrude(height = logodepth) import(file = "logo.DXF");  // importing and extruding the logo

minkowski()  // this is a transformation that adds a second shape (the cylinder) around the outside of the first shape (the cube)
{
 cube([width, length, backdepth/2]);  // a cube to go behind the logo
 cylinder(r=padding, h=backdepth/2);  // rounding the corners of the cube
}

difference()
{
 translate(v = [width/2, length+padding, 0]) cylinder(h = backdepth, r = holewidth/2);  // the outside of the key ring attachment
 translate(v = [width/2, length+padding, -1]) cylinder(h = backdepth+logodepth+2, r = holewidth/2-2);  // cut out the inside of the key ring attachement
 cube([width, length, backdepth+logodepth+2]);  // cut out so that we don't overlap with the logo
}

Rendering the 3D File

Make sure your logo.DXF file from the previous step is in the same folder as the OpenSCAD program, or specify the location in the  import(file = "logo.DXF") line.

Put in appropriate values for the variables at the top of the code (width, length, etc.).

Under the Design menu select (or press F5) and it will show you what your design looks like.

Under the Design menu select Compile and Render (CGAL) (or press F6) and it will create a rendering of your design. Then select Export as STL... under the Design menu to save your completed 3D model in a format that can be used for printing.

Printing Your 3D Model

Now that you have an STL file of your 3D model you can generate G-code and print as you normally would (likely using ReplicatorG), or you can order a printed part from an online service such as Shapeways.

The first time I made key fobs we needed 90 copies for a series of sessions I was teaching, the MakerBot Automated Build Platform was very useful for this.

Apple TV case

Playing around with a CNC router yesterday I built this: