Thursday, 24 May 2018

Free Machine Learning Crash Course by Google

I was really impressed by this introductory course for machine learning by Google. Not only is it well designed and put together, but as someone who is extremely hard of hearing, I took special interest in the subtitles for the video section.

The closed captioning is incredibly well done. It's more than just subtitles, it shows a time-stamped list of the spoken part that scrolls automatically. This is much better than subtitles for learning material, since the viewer can see not only what is currently being spoken, but quickly review what was just said as well as what's coming next.

They're even clickable so that one can skip ahead to salient parts of the video. Oh my god -- a way to skim and basically page-flip in a video. I'm on cloud nine.

I'd be happy just with subtitles, but this interface knocks it out of the park. Videos in place of documentation is more and more common, but even simple subtitles are a luxury for most learning material. Autodesk's Fusion 360 training materials, for example, are almost entirely video based and have no subtitles whatsoever.

Millions of people in North America suffer from some level of hearing loss, and half of them are still in the workforce. If your documentation is all on video where the subject matter is unfamiliar to the viewer and the speaker (and their mouth) is not visible, it makes learning far, far harder than it needs to be.

Anyway, not only is the video and captioning done extremely well in the course I linked, the course itself is really well done. If you have any interest in this area at all, give it a look.

Wednesday, 16 May 2018

What to do when STL files aren't quite right

My latest article at Hackaday is all about When an STL File Isn't Quite Right and deals with some of the shortcomings of STL files, which are used to share 3D printable designs.

STL files aren't really a CAD format, they're not intended to be edited. This is troublesome when a file needs tweaking. The thing is that 3D CAD formats like STEP (which are non-proprietary) might be a good solution, but they're not even readable by most 3D printing applications. I wonder why this is?

Sunday, 22 April 2018

Understanding Costs for Individuals and Makers

My latest column about working as a technical or engineering contractor (or freelancer) is called Lowering Your Cost Without Dropping Your Price and is part of a series called Life on Contract.

I could probably have titled it HOW A KICKSTARTER RUNS OUT OF MONEY AND LEAVES THE CREATOR A BURNED OUT HUSK and that would have been a pretty good summary of the content!

While the article mainly describes a way to lower costs without making things "cheaper" in quality, the article is also useful as a way to understand costs better.

People who are getting into making things or services -- either in business for themselves or for launching a crowdsourcing campaign -- will benefit from understanding how much something really costs in the end, and there's much more to it than the Bill of Materials.

Thursday, 5 April 2018

How To Digitally Push a Button

If you ever need to interface to an existing piece of hardware, for example because you're modifying or otherwise tampering with something, then sooner or later you'll find yourself wanting to simulate pressing a button with a digital signal.

The foolproof way to do this is to use a small relay, which is literally a switch closed by an electrical signal. However, there's another way that's cheaper and simpler. If the switch you're wanting to "press" connects an input to ground (which is very common), then you're in luck. You can do it with a single NPN BJT transistor (like a 2N3904 or 2N2222) and a resistor.


I have used this method many times in the past, and most recently used it when I modified a cheap USB mouse so that I could click the buttons with an Arduino. When mixing and matching different hardware, sooner or later you'll want to just simulate a button press and this way is smaller and cheaper than using relays and isn't fussy about voltage levels.

The transistor is used in saturation mode, meaning that it works much like a switch. When a digital signal is applied (through the resistor) to the base of the NPN, the collector is essentially connected to ground. By connecting the collector to the switch's input we can simulate the button being pressed, with no need to replace the actual switch.

Thursday, 15 March 2018

3D Printing Tools I Can't Do Without

There are few tools that I have found are absolutely necessary in 3D printing; these items are kept in easy reach and each do a slightly different job.


Starting from the bottom upwards:


  • The Scotty Peeler (specifically the SP-2 metal peeler). It's intended for peeling pesky labels but it's absolutely wonderful for getting a print separated from the build surface of a filament-based 3D printer. For larger prints where the Scotty Peeler isn't long enough to reach underneath, once an edge gets lifted with the Scotty Peeler a larger scraper can be used to lever the rest of the print. Invaluable, inexpensive, and available off Amazon.
  • Illuminated Magnifying Glass. Bought this at the dollar store. The plastic lens isn't the greatest, but the bright LED illumination makes up for it. Two AAA cells go into the handle and a switch turns on bright LEDs. I used to have a flashlight and magnifying glass together to illuminate and examine prints -- often while they were being printed. This all-in-one does the same job in a much handier package.
  • Tweezers are mainly useful for grabbing small bits and removing stray extrusions, like the bit of plastic from the nozzle after priming the hot end.
  • Deburring Tool. This item has a specialized use but well worth having. I use it for cleaning up prints. Ever have an edge that needs trimming, for example the inside of a hole or the outside edge of a print, and you can't or don't want to sand it? A cheap deburring tool from your favorite offshore discount place is what you need. If you have never seen one it might look a little strange, but it's a knife that you pull instead of push. You stick the metal curved part into the hole or lay it onto the edge, and drag it along. The sharpened side will cut off a tiny amount of material while it pivots around as needed. It's great for quick and easy cleanup of edges.
Lots of tools are useful but these have all found a niche for me. Especially the Scotty Peeler, that is absolutely #1 for me. If you 3D print and don't have anything like it, give it a shot!



Monday, 12 March 2018

2018 Hackaday Prize Opens



The 2018 Hackaday Prize has opened! $200,000 in cash prizes is up for grabs, and to get started all you need is an idea, an image, and documentation.

The Hackaday Prize has been running every year since 2014. This year's theme: Build Hope. There are many categories and there's even money set aside to help bootstrap promising ideas as the contest progresses.

Embedded below is a video that will tell you what you need to know. So if you have an idea you've been waiting for a reason or opportunity or helping hand to make happen, then the time do dust it off is now!


Friday, 9 March 2018

Using UV Resin to Smooth 3D Prints

I recently wrote up an article with the results of some experimenting I did using UV Resin to Smooth 3D Prints. UV resin is a syrupy liquid that turns solid when exposed to UV -- sunlight, for example. It's also used in SLA and DLP 3D printers like the Form 2.

The results were good. Skimming some resin from a Form 2 printer was perfectly workable for smoothing other 3D prints, and I learned what makes the resin work better or worse for this purpose and sorted out a workflow.