Time = Computers

An old saying, credited to Paul Erdős, is that “a mathematician is a machine that turns coffee into theorems.” Although I have heard other people being credited with it as well. One of the well-known versions of this is that “Computer Scientists turn coffee into urine” – obviously someone who thought that computer scientists doe not meet the high standards on mathematicians. Last night at the Adelaide Hackerspace meetup we got a new version of this:

“An Engineer is a machine to turn time into computers”

One of the fellows there – unfortunately I did not catch his name – has had a period of unemployment so, rather than head off to the beach or hide in his bedroom suffering from self-pity, he invested the time he had in hand soldering a complete Z-80 based computer. WOWZAH!

The happy maker and his wonderful handsoldered creation.

As I understood it, he has built an IDE interface to use a normal PC hard drive. Because the Z80 is an 8 bit machine and the IDE standard is 16 bit, there was a bit of high-byte / low-byte wrangling to be done. The current screen arrangement is via a serial port, which sounds remarkably low-tech until you remember that serial terminals are rare, so the easiest thing to do is to use an old laptop as a terminal: which means that the terminal is several times more powerful than the machine itself! There was some discussion about building a small (possibly Arduino based) interface for using a TV screen as the terminal, which would be totally retro and quite fantastic.

I am not sure now visible it is in the photo (I see it because I know it is there) but every connection has been hand soldered and the board is Veroboard / stripboard with the traces cut with a knife. This is a level of exactness and detail that, I must admit, I find daunting and amazing to the extreme. Congratulations!

From left to right: CPU, serial interface, IDE interface, plus a lot of logic "glue" to help it all work.


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New Towers falling over

The benefit of being far away is that one received wonderful emails about what is going on back at home:

Der Drucker druckt wieder. CM hat gestern den Y-Riehmen gewechselt und sich wieder über den Konstrukteur geärgert.

Ich hab auf ReplicatorG 24 upgedatet und ein neues Profil in Skeinforge35 begonnen.

Wieder Würfel gedruckt. Darin sind wir jetzt schon ganz gut. Nebenbei gibts Skeinforge39 und Skeinforge40. Alles nur damit wir nie aufhören müssen den Drucker zu Kalibrieren.

These: Das Objekt das Weltweit am meisten gedruckt wird ist der 20mm Testwürfel. Würde man allen Testwürfel – die Weltweit gedruckt wurden – übereinander Stapeln, würde es einen Turm ergeben der umfällt.

CM hat dann am Stepper Extruder weiter gearbeitet. Wir haben überlegt ob wir ihn überhaupt in runCNC einbauen sollen oder doch lieber in den großen Bruder von WoodyMiller. Hast du eine Meinung dazu?

A (not very fluid) translation of my favourite bit:

Thesis: The object that is most commonly printed worldwide is the 20mm Test cube. If one were to pile up all the test cubes in the whole world that have been printed, one would obtain a tower that would fall over.

CM aergert sich ueber den Konstrukteur. (CM is exasperated with the draftsman)

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Modern tools for old crafts

Build for today is a tool that is rarely seen: a netting needle. A special device for holding a longer length of twine on a bobbin/shuttle type device for making nets by hand. This is an improvement upon an older needle, which was too thin and flexible.

The needle. The gap on the left is where the line is spooled on the needle, stretched between here and the curved part at the rear (right on the image).

There are probably a million netting needle instructions online, this one looks nice. I also like the images from the lovely book from Hervey Garrett Smith.

Lovely graphics.

His book is funny in ways that I am not sure they were intended: from the frontispiece of the author onwards it is a lively read. But that is not the topic here. Tools for making tools is. So how to make the tool? the STL file is on thingiverse, we look forward to hearing about some duplicates, adaptions and mad netting made with it!

Some test netting that was made with too-thick cordage. But it seems to work!


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Voronoi code

A small update to yesterday’s post:

We are using pcb2gcode instead of visolate, which was giving offset problems between the copper traces and the drillholes. pcb2gcode does it in one go, while visolate seems to need an extra step. As well as being one of those complex  “java is a standard that is not completely standard” situations.

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PCB aesthetics

I think this proves beyond all doubt (was there ever any doubt?) that I am overgeeked. CH sent me some images the other day while I was in foreign lands showing some PCBs he had made. YOWZA!

Two PCBs milled from plain sheet. The simplicity of the Voronoi layout is wonderful!

What I really like about these are the aesthetics that arise as a complete step away from the standard etching structure that we know from standard PCB production techniques. I am sure some clever engineering types will say something about capacitance and stray signals, but I am sure that, for our electronic needs, such problems are less that significant. And we get sexy boards.

So what is being done here. Let’s start with the style. The Voronoi system has been developed by a few clever people. There is the group at MIT (yes, every clever thing happens at MIT at some point in its career – I have been there but cleverness has not yet descended upon me, obviously the other implication does not apply..) and the strange and wonderful people at Vienna’s Metalab. Seeing as we are only using this system, we will let you read what is going on over there on their pages.

What is it that we are building. New Tools for our Tools. Stepper and other control electronics.

New RunCNC electronics. Left: power area, one stepper controller is mounted. Right is Seeduino Mega, a debug layer and the input/output bit: thermocouples, limit switches and thermistors.

We hope that this new electronics part will help us have more accurate prints, as the main problem with the extruder we are using at the moment (a modified version of the MakerBot Mk4) is the lag when turning on and off.  So we get blobs when the head stops moving and turns off, and gaps when it starts to move and turns on. I am sure there is some parameter to be set up deep in Skeinforge to fix this, but better people that I will have to lead the way down that treacherous path.

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‘aesen, ‘aesen, ‘aesen!

CM is getting excited. Like all fathers he is becoming his child. “Essen essen essen” (“food food food”) seems to be his son’s favourite occupation this week, so CM’s response as he arrives in the workshop is “Fraesen, fraesen, fraesen!” (“milling, milling, milling!”) which, spoken suitably childlike, sounds about the same.

Which was precisely the task for today. After replacing one of the toothed belts that got too warm from some building process in the early stages of RunCNC, so our round gears are now round and we can finally assemble the geared extruder that is high on the wish list.

But for this we need more electronics, and more electronics is always a bit hard, so we want to make our own circuit boards, so we have put together the simplest of all mills. CM has been drilling wood and greasing nice threaded rods, CH has been fiddling with some stepper driver boards. My role has been a bit slow. But today I got to write a program with which to create some G-code that would mill out the position in the working surface that the circuit board lies in as the copper is being milled away. Which worked all very nicely except that I forgot that the first round takes off one millimeter outside the tool path as well. Oops. So our boards will need to be wedged in somehow. Double sided tape is pretty impressive stuff.

But try as I might to break stuff, the wonderful “basteln”  has paid off and the first proper milling has taken place.

The first cut! Milling through the wood word surface, a perfectly straight line!

We pumped up the voltage on the Proxxon tool to 18V instead of the normal 12V, raised the feedrate and the tool happily dug through the wooden working surface.The Woody Miller is in great shape.

Now we have it set up, the first circuit board is about to get milled. Time is on our side.

The traces have been etched (so to speak), now we have inserted the drillbit and are setting the zero point.

The milling goes smoothly, the traces separated off from the rest of the copper. We are a bit worried by the occasional copper splinter that crosses the insulating gaps. But they seem not to turn up too often.

The first PCB. Traces fine, holes were drilled a touch too shallow so they do not go through. But close enough!

Now we have the first PCB made, the next ones will not block us too long. Some teething issues with the “tool change” height being zero, so the drill bit traversed the PCB just too low and ended up snapped off. Things are looking good.

This is a very nice position to be in. We can build objects and electronics as we want them, within certain limits of exactness. There is a whole swathe of programs and systems out there to build strange things. People doing strange things and sharing them, encouraging us to do the same.

This looks like fun.

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configuration configuration configuration . . . . . . .

Sunday. Rainy Linz weather. Summer was a Tuesday. Now it will be like this until a pseudo “Indian summer” or Altweiber (old lady) Sommer in October.

But do we care? No! We have about three dozen Skeinforge parameters to tweak and twiddle, options of rafts, things like “extrusion width over thickness” to decipher and a whole row of experimental sculpture objects to produce that should be recognisable objects like cubes, gears or some other regular polyhedra. All praise Plato.

In all fairness our two 20mm cubes were pretty cubelike. At least the ones that did not die in the middle of extrusion. But the 10mm cubes are somehow Dali meets Kepler and the attempted gears yesterday were more like a melting tower of Babel.


Today things are not really any better.

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