It is one thing to make things, but another to make something that itself makes other things. That is what I have tried to do here. Inspired by the amazing achievements of the RepRap project, I built my own three-dimensional CNC positioning system, mainly. using parts from old typewriters and inkjet printers.

Note – I have produced a publication based on the development of this machine, entitled To err is almost human.

It is one thing to make things, but another to make something that itself makes other things. That is what I have tried to do here. Inspired by the amazing achievements of the RepRap project, I built my own three-dimensional CNC positioning system, mainly. using parts from old typewriters and inkjet printers.

I was very impressed with the electronics and firmware used by the RepRap printer, which make use of the Arduino experiment board to interface to the computer. The Arduino has an on-board microcontroller which means a lot of the timing and control can be done by the machine, rather than the computer. I have made use of the same electronics as RepRap (including PCB’s purchased from the RepRap Research Foundation (RRRF) Store).

This project has been ongoing for a while now, and has progressed quite well. It can draw very effectively, and I have recently started some experiments carving Styrofoam. The next step will be wood and possibly aluminium, although this would really be testing the strength of the thing.

As well as this, I have learned a lot though the process of building this machine. I intend to use this knowledge in the future to continue building similar, better machines. In fact, it should be possible to use this (version 1) machine to make some of the parts for the next generation.

Of course hardware is not so much use without an appropriate control program, so I have also written some software to control it. This can be found at my G-code for RepRap page.

Carving cube man

Three-axis CNC robot drawing test

A program which I have written to read G-code files, the standard format for controlling CNC machine tools, and output this to the electronics designed for the RepRap project.

The RepRap project is a very exciting development in open-source hardware. It’s a machine for which the eventual aim is to have it make copies of itself, which is of course quite a tall order. It is a sort of computer-controlled robot which squirts out hot plastic in a controlled way, building it up in layers to make a solid object. When I read about this project I became very interested in its possibilities, particularly for artistic purposes. In theory it should be able to make almost any shape which can be imagined. The possibilities are endless!

As a stepping stone to building a full version of the RepStrap (the name given for a machine not built from self-generated parts, but designed to make the first generation of parts), I have built a 3-axis Cartesian robot from typewriter and inkjet printer parts, with the idea that I could attach a small drill to it in the meantime and use it to mill shapes from wood, plastic, maybe even aluminium. Building the thermoplastic extruder needed to start building things using additive manufacture looks like being a lot of work (and more importantly time), and so the subtractive (milling) option seemed a bit less daunting. More about my machine here.

The RepRap firmware has the ability to read G-code files, the standard format for controlling CNC machine tools. What my program does is provide a graphical user interface for this, allow the user to load a G-code program and run, stop, and pause this, as well as manually enter G-code. Additionally, there are jog buttons to allow manual positioning of the tool head before starting a program.
Suggested CAD software for producing .DXF files;

• Solid Edge 2D – this is a free version of a commercial 3D cad system. It seems very much like AutoCAD in how it works, and for me at least took quite a bit of getting used to. I have also used it to produce the drawings for my pedal steel guitar. Of course it is only 2D and so it would be necessary to produce a layer for each height in the cut profile, and assign a Z-dimension to each when converting to G-code. This is possible using Ace Converter (below).
• QCad – Open source, quite mature and powerful. Also only 2D. Works well.

I will try to add some more here when I get a chance to investigate some more. Suggestions most welcome!

Some utilities to convert .DXF to .NC (G-code) files, as needed by G-code for RepRap;

• CamBam – Windows-only program (no luck with Wine so far) which is extremely powerful and almost a CAD program in itself. I have had good results with DXF files produced in QCad. Highly recommended.
• Ace Converter – open source and seems to work pretty well, except that it does not insert feed speed commands; these need to be inserted manually. Windows only (works with Wine under Linux). Note that it seems to crash when reading large files.
• CAD2CNC – an ancient DOS program which I came across on the internet (Google it). Seems to be quite powerful. It doesn’t work in Windows, but it may be possible to get it to work using VMware or something similar.

Another use for this machine may be milling PCB’s. I have found at least one piece of software which is free and can produce G-code from Eagle files as well as Gerber files. I have not yet tried it out with G-code for RepRap.

This software is GPL licensed (which means it’s free in all senses of the word).

A video of it in action can be seen at my three-axis CNC robot page.

Download G-code for RepRap from Sourceforge

I wanted to build an ultra-quiet PC to be used for playing DVD’s, MP3’s, downloaded films, watching (and pausing) live TV, and such like. It runs the Freevo home theatre platform on Linux, and features an IR remote control (with wake from standby functionality), an LCD display, TV-in and -out, and can barely be heard even in a completely silent room.

I wanted to build an ultra-quiet PC to be used for playing DVD’s, MP3’s, downloaded films, watching (and pausing) live TV, and such like. It runs the Freevo home theatre platform on Linux, and features an IR remote control (with wake from standby functionality), an LCD display, TV-in and -out, and can barely be heard even in a completely silent room.

The first task was to identify what the components are which generate noise. These are;

• Fan in power supply
• Processor fan
• Hard drive
• Optical (DVD) drive

The first of these I tackled by constructing a passively-cooled PSU, that is to say a power supply without any fan at all. This I did by mounting the power transistors from an existing ATX power supply onto a very large aluminium heatsink, so large that it remains cool without air having to be blown over it. Since there are lethal voltages within a PC PSU, I then made a cage out of perforated steel to cover the whole thing. This is the large box at the rear of the machine which can be seen in the photos with the case off.

To solve the processor fan noise problem, I attempted to run the system using a passively-cooled Slot 1 PIII processor. Unfortunately, the fastest available was still not up to the job, and so I went looking for the quietest fan I could find. The one I have used is an Acoustifan, which when run at 5V (rather than the usual 12V) is almost inaudible, even at night.

The hard drive is a 2.5″ laptop hard drive connected via an adapter cable, which is also extremely quiet. To prevent vibrations from this transferring to the chassis, it is held between two pieces of foam rubber. The fact that the chassis is made from 18mm MDF, which has quite a high density, means that the whole thing does not resonate as much as a folded steel case would.

The area in which I had the least success was with the DVD drive – I could not find very much objective information online about really quiet drives, and ended up buying a couple which had been recommended on forums via eBay. The one which I have is still not ideal, but quieter than many others which I have come across. Some drives can be set to spin at relatively low speeds via software, but this one does not seem to respond to such commands.

As mentioned, Linux is the operating system installed on this machine, or to be more specific Mandriva Linux 2007. The DirectFB system is used so that no windowing system is needed, thus reducing system resource requirements. This is important since the processor is a PIII 1000MHz, about the lower limit of what can be used for this type of system.

TV out is provided with a Matrox G400 graphics card, which although pretty old has quite good Linux support and produces a fairly good picture (much better than the photos would suggest; it’s pretty difficult to take reasonable shots of an analogue TV picture!).

For watching TV, I have a Hauppauge WinTV-PVR-150 analogue TV card, which is the most appropriate here in the Netherlands where the majority of homes receive analogue cable TV through a coaxial wall socket. At some point in the future, it may be that it will need to be upgraded to one or other digital system.

I was very keen that it would be possible to put the thing into and out of standby using a remote control, just as is possible with most set top boxes. It took quite a bit of fiddling to get the system to enter suspend mode properly (and more to the point, come out of it), and indeed it turned out to be easier using the older APM system in Linux rather than the more modern ACPI.

The remote control is the one which came with the PVR-150 card, with a simple detector circuit wired up to COM1 as required by LIRC.

To get the system out of standby using the remote control, it was necessary to construct a small circuit which would detect the IR code for “on”, and send an interrupt to the computer via the WOL (Wake-On-LAN) connector.

Finally, a small 20×4 character HD44780 LCD display allows control of the system without the TV being on, which is useful when for example playing MP3 tracks. This makes use of the LoS-panel circuit, which interfaces to COM2 and allows the backlight to be switched on and off in software, which is used to power it down when in suspend mode since power is still supplied to the LCD display.

For practical reasons (cooling), and also because I quite like the look of the G5 Mac, I had a perforated steel case made to cover the MDF chassis. This was not too expensive, and works really well. The front panel is made from 6mm MDF, and both it and the case are finished with spray paint: matt black for the case, and dark metallic indigo for the front panel.

You will know it when you hear it; the beautiful, smooth sound of a slide guitar. Most of all in country music, but also in many other styles. Unable to afford one, and of course because I love making things, I decided to build my own.
You will know it when you hear it; the beautiful, smooth sound of a slide guitar. Most of all in country music, but also in many other styles. Unable to afford one, and of course because I love making things, I decided to build my own.

This beast has been over two years in the making, and is now a complete redesign of my original attempt, put together as it was in an afternoon from salvaged guitar parts and MDF. What has taken by far the most amount of time is designing a reliable string bending mechanism. The current incarnation is composed of Meccano, extruded aluminium, and hardware purchased at my local ALDI. Precision engineering is this thus definitely not. However it does work, and keeps its tune pretty well.

The legs have been salvage from an old card table (the sort which is roughly 1m square and is covered with green cloth), and possess a nice locking mechanism. In addition to the main guitar table and pedal base, the instrument features a folding stool which forms part of the case when packed away.

Playing the pedal steel guitar

I built this during the time that I was a participant in the artwork Beautiful City by Maria Pask, which took place during the summer of 2007 as part of Skulptur Projekte Münster 07. I had always wanted to construct some type of bicycle, and this proved to be a good opportunity to do so.

I built this during the time that I was a participant in the artwork Beautiful City by Maria Pask, which took place during the summer of 2007 as part of Skulptur Projekte Münster. I had always wanted to construct some type of bicycle, and this proved to be a good opportunity to do so.

The intention of Beautiful City was to build a city of ideas in place of one of concrete and stone. A large tent was set up in the Schlossgarten in Münster, where a talk was held every Sunday by a representative of a religion or belief – including a Buddist heavy metal band, no less than two witches, and a lesbian catholic priestess. At the same time, the city was populated by a different group of people every week, most of whom were art students from the Netherlands – including myself.

The equipment which I had available was pretty limited, which made things quite difficult. All the parts which I needed were salvaged from the nearby university, and hauled through the streets of Münster to the park where we were staying.

It went through a couple of versions before it was able to work successfully, and it must be admitted that it is not the most practical thing I have ever built. It’s really heavy, and also a bit dangerous if someone sits on the front without there being someone on the back to counteract their weight. This became a bit of a problem during on of the Sunday lectures, when a German Buddhist named Winfred Kopps decided that it would be nice to deliver his talk whilst sitting on the bicycle. We tried hanging jerrycans full of water on the back, which was not too successful, and so instead myself and one of the project organisers took it in turns sitting on the back while he spoke. Happy memories indeed.

ShopeShapes is a piece of computer software which allows an oscilloscope to be generate vector graphics using the sound card output of a computer. It reads 2- or 3D shapes from .dxf files, and allows up to ten such shapes to be rotated, zoomed, and morphed in real time. It runs on Windows, Linux, and Mac OS X.

I bought an oscilloscope cheap, and it seemed like fun to try and make it do things it wasn’t designed for. For those who are wondering what on earth an oscilloscope is, here is a bit of background…

An oscilloscope is a piece of laboratory equipment which has a small screen, various controls, and inputs for electrical signals. Its normal mode of operation is to trace voltages over a certain short period of time, say a tenth or a hundreth of a second. The horizontal axis represents time, and the vertical axis voltage. An electrocardiogram display as might be used in a hospital is a specialist form of oscilloscope.

However, the one I have (and most models, for that matter), has a special mode whereby the horizontal axis can be controlled by a voltage as well, rather than by time, such that a line can be drawn to any point on the screen by varying two (rather than one) voltages.

I did some thinking, and realised that the stereo sound output that most computers have is just 2 digital-to-analogue converters, that is the it is just 2 voltages that are under software control. So by writing some clever software, and connecting, say, left to X, and right to Y, we could produce pretty pictures on the screen! Without having to build any additional hardware!

This is what ScopeShapes is for. Of course, a picture speaks a thousand words – have a look at the photos for a better idea of what it is all about.

ScopeShapes reads in DXF files, which are produced by AutoCAD, and many other programs – they are basically a CAD-orientated 3D vector format. I chose this because it is a pretty common format, and the specifications for it were freely available. It can hold up to 10 shapes at once, and switch smoothly between them. This can be done with the mouse, or via keyboard shortcuts.

ScopeShapes runs on Windows, Mac OS X, and Linux.

Download ScopeShapes from SourceForge

Read the ScopeShapes manual (pdf)