Monthly Archives: November 2014

iBooks

Interactive Video Widgets in iBooks

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For the last couple of summers I had the pleasure to work along Tony DiLaura, Dave Bast and some great educators committed to making their own content with hopes of replacing traditional textbooks at iBooks Hackathons. I’d put together some material for those hackathons and I thought I’d share some of it here.
When I teach I try to always ask questions and never give answers. I want my students to struggle a bit and discover the answers through experimentation and discussion. This is very difficult to do in the videos I make. Due to the nature of video I don’t really give students time to think, nor do I give them a chance to investigate different answers. Derek Muller hit on a solution to this on his Veritasium YouTube Channel. YouTube allows you to put clickable hotspots on videos. Derek uses these to link to other videos he’s made. He set up a kind of choose your own adventure allowing viewers to think about different answers to questions and each answer has it’s own video.
I thought this was an awesome way to get students thinking and set out to try it myself. But as it turns out, these hotspots don’t work on mobile devices, including iPads. We’re in the midst of becoming a 1:1 iPad school, so I don’t want to rely on cool internet features that I know won’t work on mobile devices.
After some though, I realized I could create the same sort of effect using either Keynote or Tumult Hype. Once created I can drop them into an iBook as an interactive widget and my students will be able to actually grapple with questions in their book rather than simply being presented with the answers. Each solution has its own advantages and disadvantages. Here’s the version I made with Hype (I’m not sure this link will work correctly) to use with my students.
One big advantage with Keynote is it is easy to work with and if you have a Mac you probably already have it. Keynote’s biggest disadvantage is there is no way to control the video once it starts in an iBook widget. The video starts and then runs to completion, no pausing or rewinding.
In Hype you do have the video controls. The other big advantage in Hype is you can embed YouTube videos. I don’t know of any way to have YouTube videos auto-play in Hype. As far as I know, there is currently no way to embed a YouTube video in a Keynote. Embedding YouTube videos means you must have internet access to view, but it keeps the iBook size down to manageable levels. Unfortunately Hype is not free. It costs $30, but if you’re going to be making iBooks it might be worth it in the long run. Make sure you buy it through the Tumult Education Store to get the discounted price.

Instructions:

Make your Keynote Presentation “Links Only”:

Keynote for Interactive Video:



Hype for Interactive Video:

Putting YouTube Videos in Hype:

3dprinter

Getting Started With 3D Printing – PLA vs. ABS

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There are two main types of plastic used in most FDM printers, polylactic acid (PLA) and acrylonitrile butadiene styrene (ABS). ABS is the same plastic Legos are made from and PLA is a bioplastic typically derived from corn starch. I will not go into a lot of the technical differences, but will instead focus on the practical issues related to each type of plastic.

Each plastic has its own advantages and disadvantages. Most of the newest low cost printers available today will only print with PLA. In order to complete a successful print, the plastic must stick well to the print bed. Sometimes it may be beneficial to heat the print bed to 40-50°C for PLA. However, it is often not necessary and many commercially available printers designed to print with PLA do not have the ability to heat the print bed at all. ABS requires a heated print bed for parts to stick. It is necessary to heat the print bed to 110-130°C when printing with ABS. This is quite hot, remember water boils at 100°C.

There are other practical concerns related to both plastics to consider. ABS shrinks substantially more than PLA while cooling. This can often cause parts to warp. When a part warps the edges or corners lift off the platform. This can lead to a part becoming completely unstuck from the platform or even if it stays in place may be completely unusable. ABS also gives off some fumes while printing. They are not overwhelming, but they are noticeable. One of my colleagues has sever allergies and asthma and reacts to just about any type of smell or fumes in the air. She never had a problem with the ABS fumes in the room.

Since PLA doesn’t shrink as much as it cools it is much less prone to warping and the finished parts are much closer to the intended dimensions. This difference often doesn’t mean much. However, if you are printing something like a phone case it is much easier to design one that fits just right if you print with PLA rather than ABS.

Given the minimal shrinkage, lack of fumes, and no need for a heated bed you might be wondering why I’m even presenting a choice between ABS and PLA. PLA seems to be far superior in almost all respects. One factor to note, however, is it is far more finicky to print with. With PLA, if things are not perfect the printhead can become clogged. This is not a problem I’ve ever had with ABS.

I was so fed up with problems related to ABS that I’ve been printing exclusively with PLA for the last couple of years. For the 9 months, with my first generation Replicator, I have not been able to print something that takes more than an hour and a half before the print head jams. Often it jams much sooner. Newer printers may be more reliable, but I don’t have experience to speak to that. Yesterday I switched back to ABS and was able to do a two hour print of a comet and a five hour print of a fossil skull with no problems. For my printer I may switch over to mostly ABS and just print in PLA when I need something that fits precisely.

While I’m talking about Plastic I should mention that both types should be stored in sealed containers. Over time they will both absorb moisture and this could cause problems while printing. I use a container designed for long term storage of food and I toss in some silica gel to absorb moister. The container I use was less than $15 on Amazon and will hold two spools of plastic. The other bonus with using containers for storage is it will keep your plastic relatively dust free. If dust accumulates on the filament it can cause the print head to become clogged.

Go Back to earlier parts in the series: Part 1, Part 4

3dprinter, tinkercad

Getting Started with 3D Printing – Jazz Hands

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In my last post I walked you through creating a relatively simple cell phone holder in Tinkercad. In this one I want to show you how easy it is to modify an existing design. You can do this with your own models or you can do this with ones you find online in places like the Thingiverse.

We’re going to add a design to our phone case we made in the last post by importing an image in svg format. svg files can be imported, resized and extruded into 3D objects. I’m going to use a public domain image from Pixaby. I like Pixaby because all the images are public domain. They do have svg files available for download, however, I haven’t had any luck importing their svg files into Tinkercad. Instead I find an image (png or jpg) I like and convert it using the Online SVG Image Converter. You’ll want an image that is only black and white (literally black and white, not greyscale). If your image has any grays they will be treated as black when imported into Tinkercad. The image I chose has some grays, but I think it will look fine as black and white.

Basically you just import your svg file, resize it to fit, and the position it where you want it to go. You can either do this as a raised pattern or turn it into a hole and use it as a recessed pattern. You can find full directions in the Google Presentation below.

Go Back to earlier parts in the series: Part 1, Part 3 or go on to Part 5