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Showing posts from October, 2015

Banging my head with Java line separator

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One of the most unpleasant experiences with computers is having to solve a problem you already fixed when you
realize the old solution is no longer working for reasons unknown.

The problem this morning was quite silly, actually. One piece of code created a text file. I did not care much about the way newlines were represented but when  I sent the file to to a colleague that uses Windows he complain notepad was making a mess out of it.

It was clear notepad was doing this because my file, created on a unix system, did not honor Windows end of line convention of CR plus LF characters (0x0d + 0x0a). I have solved that in the past just changing the System property called line.separator. You could do that with System.setProperty("line.separator","\r\n") but apparently not anymore. Of course, no error message or exception is raised, so you are left alone, in the dark, trying to figure out what is wrong and why what worked before does not work now.

I could not make much s…

The right interface

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When I was a teenager I was an avid reader of electronics magazines. What was available at home at first and later what I could afford. I remember that my favorite ones was Elektor magazine, that grew from a German-only magazine to be distributed to other languages and countries, mine included. They have this great summer edition that included over a hundred different small circuits.

Over the years I have almost stopped buying magazines (not because they are bad but because they use shelf space and I have not much time to read them). The last paper copies I bought were from Circuit Cellar Ink, but these same guys decided that a digital edition will ease their business, and for those abroad it will be be much cheaper. Selling bits is a good idea that seems to be making Google and many others much good. I even wrote several articles for Circuit Cellar magazine about different projects I made.

A few years ago I learned that Circuit Cellar Ink was acquired by a European group that handled…

First impressions on bq's Hephestos 2

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I was asked to be a beta-tester of this new machine sold in kit form by Spanish firm bq.  It's a bit hard to keep the experience to myself while the testing was taking place. I won't say it is great and rosy but their approach was a bold one and I think it stands out of the crowd.

So what is it? Hephestos 2 is a 3D printer kit to be assembled by the user. While it might find its routes in Josef Prusa iteration 3 model, this time it is just a faded image. That was entirely the case with the former Hephestos that shared most of Prusa i3 features with a few of exceptions: no heated bed, a couple of cable chains and a very well engineered extruder/hotend combo.

But the Hephestos 2 breaks with the Reprap tradition and includes no printed parts and a body made of powder colored folded metal parts. Only Y-axis uses 8mm diameter smooth rods and linear bearings but Z and X-axis use miniature Hiwin linear rails for extra accuracy. A new electronics board integrates an ATmega 2560 plus f…

More on DC motor "stepper emulation"

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The code I developed a while ago for using a DC motor (or a BLDC) to replace a stepper has got quite an interest among youmagine users. Over time I realized that some of the quick and dirty things I did were preventing the easy exploration of system parameters for users. Using different PID parameters required a recompile and of the sketch.

I recently received a Printrbot Simple from Brook Drum with the goal of testing with that printer my closed-loop solution.  As usual, simple things (in theory) become tougher that initially expected. First of all, it took forever for the printer to clear through customs and while Printrbot provided and shipped the printer for free, the taxman wanted its cut no matter what, and it took more than too weeks for that to be worked out.

We settled on the Simple because it had more room for the motors to fit in though carriages might be heavier than the Play.



At the time I did not know the CAD of both models was available on Youmagine, so I only had a vag…