All articles in tricks

Finding rotation speed using Arduino

Ooops, it’s been a while since I was last active here, sorry about that.

But to offer someting in retribution, here’s a device that can count revolutions or any other event that closes a switch, and tell you how many times that happens in a minute.

I have a need for this device, because I am building a dolly for timelapse images. The dolly has a 2m long worm screw that makes the dolly travel along an axis. If the trip takes, say, 3 hours, and the dolly carries a camera that is set to take an image every 5 seconds, we get a 3 x 60 x 20 image timelapse, ie. 4,800 images. With 25 images per second in a video, that gives you a 192 seconds, or, a little over 3 minute time lapse. During which the camera moves, you see, it’s not just a timelapse.

Continue reading Finding rotation speed using Arduino

Printing gears, part II

Now that we have covered the somewhat tricky route of tracing gear curves from images (which, by the way, you can use to create meshes out of any image) in part I, let’s have a look at the eMachineShop way. eMachineShop is a free gear designing software from the firm by the same name. They allow you to use their proprietary software for free in personal use, and then you can order the final product from them in a variety of machining finishes. I commend such an approach, especially since the software exports pure STL for our needs.

You can download the software package from and install it. When you start it the first time, you see a tutorial screen, but you can turn it off once you have the hang of the software. As it happens, it is very powerful, but a little quirky.

The main window looks like this: Continue reading Printing gears, part II

Solving everyday niggly bits with 3D Printing

I don’t know about you, but I am one to get irritated with stuff that hangs out in the wrong places. A good example is the chest strap of the computer backpack: I never use it, but I don’t want to cut it off either and harm company property. Instead, I made a quick mesh in Blender and printed it out on the Minifactory, with the net result of straps no longer hanging around causing me to lose hair even further.

Here’s the starting situation:

Messy straps
Messy straps

And this is the finished, improved situation:

Better situation
Better situation

Let’s have a look at the fixing clip.  Continue reading Solving everyday niggly bits with 3D Printing

Printing Fractals on MiniFactory

Last week, we had our 8th International IT Week for Students here at HAAGA-HELIA where I work. We had teams from Spain, Denmark, and Finland, and we looked into issues like mobile games development, robot building on the Arduino set, and on the Danish day, fractals. My good friend and colleague from Coopenhagen North, Anders Kalhauge, presented a lecture, and the students then led a workshop into fractals.

Fractals are odd creatures. Wikipedia says that

“A fractal is a mathematical set that typically displays self-similar patterns, which means it is “the same from near as from far”. Fractals may be exactly the same at every scale, or, […] they may be nearly the same at different scales. The concept of fractal extends beyond self-similarity and includes the idea of a detailed pattern repeating itself.” Continue reading Printing Fractals on MiniFactory

Things I have learned of MiniFactory

I have now had the wonderful MiniFactory 3D printer for about three months. As I have little teaching with contact lessons, and hence no need to go to the University every day, I haven’t been able to print something all the time. Nevertheless, I have become somewhat proficient in managing the printer, so I thought I would write a little blog post to illustrate some of the stuff I have picked up along the way.

MiniFactory is located in Seinäjoki, Finland, and its manager Janne Pihlajamäki has been instrumental in getting our machine to work properly. I have contacted him on email and phone, and he has never failed to provide an answer to my questions. He probably thinks me a very nontechnical person, what with the million questions I have sent him, but on the other hand, he’s been getting the word back from the trenches. I hope this is a mutually beneficial set-up. MiniFactory is a startup company, and hence, they have been too busy in building the production line and the machines themselves to get all of the documentation in place yet, but they are doing an admirable job at this difficult business.

Continue reading Things I have learned of MiniFactory

Word count Excel for authors

I never started writing after a conscious decision. Tulagi Hotel, my 134,000 word novel, came about after I chanced to write the first chapter at the office, over an extended coffee break, and with no intention of making it into a full-fledged book.

But when it was published, I found myself writing short stories. In a span of six months, I wrote 16 stories. At this time, I became interested in tracking the word counts of the stories. This is interesting for two reasons: most short story competitions have word limits, and it is nice to know the progress of your Work in Progress (WIP) files. Of course you can just note the word count and manually copy it to an Excel sheet, but I thought to make that process automatic. I will explain how, and also, share my file under the CC-BY-NC license. Continue reading Word count Excel for authors

Powerpoint and image processing

Sometimes we all have a need to write instructions, or add information to an image, or combine many pictures to one. Of course you can do this using an image processing software such as Paint, GIMP, or Photoshop, but many times these are not available. And of course, what you can do in Paint is crude in the extreme, because it is a bitmap editor and not a real image editor.

Paint especially is not very good for this sort of work, because its resizing capabilities are not up to par, and whatever you insert into the picture gets inserted in it for good – revising text or moving an image in a composite are not possible. Using GIMP or Photoshop is somewhat easier due to the use of layers, which enables you to maintain texts and other adornments in editable form before you export the image, but the set of available arrows, stars, and other thingies is not very large without installing plug-ins.

Continue reading Powerpoint and image processing