Monday, 5 February 2018

3D Printing Glue Sticks (it's not as dumb as it sounds, I swear!)

I put up a 3D model and info on GitHub to go with an article I wrote on making the PLA Glue Gun. The PLA Glue Gun is quite simply a glue gun that extrudes molten PLA instead of hot glue. For some purposes, that turns out to be remarkably useful.

Monday, 22 January 2018

3D Printed Star Wars Death Trooper Helmet Reveals Neat Inner Geometry

I printed this model of a Death Trooper Helmet (from Star Wars Rogue One) at 2 perimeter walls and 10% infill. While printing the thin sections, the infill pattern can't be discerned - it's just an inner line here and there inside the thin wall.

However, after putting all the pieces together I could see the patterns the infill structure made. I took some photos after putting a light bulb inside to highlight things.

It's pretty cool that even though the pieces were printed separately, some of the infill pattern geometry nevertheless appears to line up between the pieces. Neat!

Thursday, 28 December 2017

Review: The 3D Printing Handbook

Near the end of 2017, 3DHubs released the The 3D Printing Handbook which is an accessible design reference manual for the different 3D printing technologies available to hobbyists, professionals, and enthusiasts. The book covers different technologies, their strengths and weaknesses, and how to best design for their capabilities. It also has case studies of different 3D printing technologies and their impact in different industries.
3DHubs is a "3D printing as a service" site that connects people who want something 3D printed to people with 3D printers (and vice-versa, allowing 3D printer owners to provide a service.) Since the whole idea works much better the more people know about 3D printing, 3DHubs puts a lot of work into education to build familiarity with the concepts, with a large knowledge base with guides such as Practical CAD Modeling of Enclosures for 3D Printing. The new book is in a similar direction, aiming to be a reference for engineers, designers, and hobbyists alike.

3D printers are amazing tools, but they are not magic. Like any other manufacturing tool, a 3D printer has things that it is good at, and things it isn't so good at. A part needs to be designed in a way that works in harmony with the abilities of the chosen manufacturing method, a process knows as Design For Manufacture (DFM) and it's important whether you're just making one or two, or mass producing. The 3D Printing Handbook is a reference manual that not only guides people in choosing between different 3D printing technologies, but also guides designers in applying sensible DFM for objects that will be 3D printed.

That is the main focus of the book; a tour of what 3D printing technologies are available right now, their strengths and weaknesses, what industries they are used in, and basic DFM design guidelines for each. Everything is presented clearly and succinctly. Interested? 3DHubs has links to where you can buy the book in your preferred format.

Wednesday, 8 November 2017

Making a Tiny Luger P.08 on my 3D Printer

Made from individual parts
I made a teeny tiny Luger P.08 pistol on my 3D printer. Not just a model, but I printed the individual pieces and assembled them.

It wasn't easy. In fact, while the pieces themselves printed out astoundingly well considering their tiny size, at such a small scale the tolerances just don't match well. Pieces that need to fit into other pieces just didn't go. Being off by a fraction of a millimeter is quite a lot when the pieces are so small to begin with.

With a lot of patience and sanding of some of the larger components, I was able to do a pretty good (if frustrating) job of assembling the pistol in clear resin!

I have been asked about model kits but this is just a demo piece; I wouldn't subject anyone else to the amount of work it took to make. At least, not yet.

A gallery at is available as well.

Friday, 20 October 2017

Less is More: The Low-Tech High-Tech Cat Tracker / Cat Finder

Lunchtime in the woods
My cat and I spend time together outdoors. She loves being outside and I love being out in the woods with her while she gets a chance to just be a cat. We stick together, but it's not always so easy for me to see where she is. I decided to try to apply a technical solution to this. I don't have a full solution, but in the process of testing I ended up with a low-tech application of high-tech parts to solve some of my needs.

I created a remarkably functional cat finder without soldering a single wire nor programming a single line of code.

She blends in really well.

The Problem

Because she blends in so well and is much more mobile in the woods than I am, I sometimes lose track of her.  For example, she leaves the trail and I'm not sure if she's sitting six feet away, or if she started prowling around in some direction. Also, there's the worst case scenario that we somehow get seriously separated.

These issues led me to start to think about a Cat Tracker/Finder and what I wanted it to do:

  • Help me locate the cat when outdoors together if I lose track of her
  • Help me find the cat if we get seriously separated from one another and she is lost

There are many cat and pet tracker products and projects, but many are not complete, and most of them do not do what I want them to do anyway. They mostly log your pet's activity for later downloading and analysis, they're not made to answer the question "Where Is My Cat Right Now?" The project that seemed to get the closest to what I had in mind was this one, but it was clear I would need to design and investigate on my own.

Towards a Solution

When I started thinking about a design that would solve ALL my problems, I came up with a wireless GPS tracker that was able to communicate its position wirelessly and long-range. But before going down that road I tried something simple: a bluetooth low-energy beacon on the cat's collar. At first I was just intending to measure BLE range in the woods, because green leafy and woody things are good at blocking radio signals, but I stumbled onto something useful in the process.

I ended up using a BLE Trackr,
but not for its intended use.
I had gotten a device called a Trackr Bravo as a gift, but found the Trackr and its companion app to be useless. It was not useful for tracking household items like keys or remotes, let alone a living creature in the bush. However, it turns out that the device itself could still be made useful. All I needed to do was turn it on -- no need to pair to it or communicate with it in any way -- all it needs to do is broadcast, which it does automatically.

Then, on my phone I installed a BLE Scanner app. All it does is scan for and display BLE devices in the area, and display their names and signal strengths. The Trackr shows up with the name "tkr" and a signal strength.

Originally I intended only to use the setup to measure BLE wireless ranges in leafy brush, but I quickly realized that the BLE Scanner plus a "bare" and un-configured BLE beacon were in fact a highly effective short-range Cat Detector. It ended up being remarkably useful!

The Low-Tech Solution

The combination of BLE Scanner plus a "dumb" BLE beacon is powerful. If I lose visual track of my cat and am not sure whether she is in the immediate area or not, I can fire up my phone and start the BLE Scanner. If I see a "tkr" device, with any signal strength at all, I know that she's nearby even if I cannot see her.

If I don't get a signal, I can hold the phone vertically as if I were taking a photo and point it in different directions. My phone's bluetooth antenna is slightly directional when doing this -- it has a little better reception but mostly only in the forward direction. (I discovered this because standing around in the bush while your cat enjoys being a cat gives you a lot of time to discover these little details.) The phone's bluetooth antenna can therefore be pointed somewhat in different directions to try to pick up the signal.

If that still doesn't get me anywhere, I know that she must have moved a little further away without me realizing. Slowly walking a short distance up and down the trail (first one way, then the other) while keeping one eye on the phone usually does the trick. Failing that, start an outward search pattern while watching for "tkr" to pop up on the scanner.

Usually though, I find her before it comes to that. By the time I am stomping noisily through the bush, she comes to investigate the noise and see what my problem is.

If all else fails, I cast a summoning spell. (In other words I call her name, I make kissy sounds with my mouth which is "the food sound", and I rattle a treat bag.)

Lessons Learned 

An important thing I realized while testing and prototyping was that I didn't actually need to know my cat's exact location. Both in a practical sense as well as for my own mental well-being, simply knowing that she's somewhere in the immediate area is good enough. Just by using a BLE Scanner app and a "dumb" BLE beacon, I can tell whether she is near. This also tells me whether she has moved or not (i.e. if she was near before, it tells me whether she is still near. If not, she is on the move.) By familiarizing myself with my phone, I discovered I can hold the phone in a particular way to use the antenna directionally to help with finding a signal.

Previously, I had no way to know anything about her position that my eyeballs could not tell me, and as you can tell from the pictures at the top of this post, eyeballs are a really, really limited way to keep track of a bush-colored cat in the bush!
No nearby devices - she is not in the immediate area (up to 15-25 foot radius)

There we go! Picked up the signal. She's nearby, and that's really all I need to know.
This solution doesn't address all my wants. It wouldn't be of very much use if we get seriously separated and lost from one another, but it's remarkably useful for what it is: two high-tech devices used in an extremely low-tech way. The accessibility of the parts and the interaction between them is where all the value comes from, and there's a good lesson in there about how problems get solved and why some solutions are useful and others aren't.

Wednesday, 19 July 2017

3D Printing Pen Tubes / "Shells"

I tried an idea I got from a souvenir a friend showed me, and designed a Pen tube or "shell" that is made to accept standard Bic pen refills.

Inspired by the iconic phrase "END OF LINE" in the original TRON, I think it turned out quite well.

This was printed on a Raise3D N2 using eSUN PLA+ filament.  Raise3D has an absolutely fantastic house-brand premium PLA which is too expensive to ship to Canada, and it's only available direct from Raise3D.  However, I've found eSUN PLA+ (I order from to be a close second.

I think it would turn out even better on a resin printer like the Form 2.

If you want to make your own, a Bic pen insert is a 3.95mm diameter shaft 9mm long (this is the short area directly behind the cone that is the tip -- it goes into the tube and is held by friction.)  The ink tube area behind is close to 110mm long.  Make some 3D text, put a cylinder through it to stick the letters together like a shish kebab, then make a void inside with the measurements above. It worked first time for me, hope you have the same luck!

Wednesday, 7 June 2017

Making a "Filament Out" Alarm for a 3D Printer

Mister Screamer V2.0
I came up with a new design for a filament alarm that let me continue large prints even if the filament spool runs out. I called it Mister Screamer and I showcased it on in an article called Let's Prototype! This Filament End Needs 80 Decibels.

I also refined the design further in a followup entitled Improving Mister Screamer; an 80 Decibel Filament Alarm where I solved some of the problems I discovered the first time around, and changed the operating principle. I used this project as a means of showcasing the iterative prototyping process.

The device works by hanging from the filament line like an ornament or pendant. When the filament runs out, the device falls to the tabletop where it begins shrieking loudly, alerting a nearby operator that it's time to change the filament spool. No modifications are needed to the filament or to the printer. There are some images below; for more details, visit the links to the original articles above.