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Just a few photos and a video from the 3 days of training I took part in which started on Monday the 11th of July. In the 3 days we put together 2 machines; one that was a gantry based plotter and the other was a turn table based scanner. The interesting part was tooling the plotter to pour slip over clay. The pictures below are just a few photo I took over the 3 days. Mat, another from the CNC workshop documented the whole process better than I did, you can find his photos here

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Recently I attended a 3 day training session on building home-brew CNC machines which was run by Dave Turtle from the RCA. It was an amazing 3 days and I will post the photos and videos of the results as soon as possible. One of the hurdles that came crashing in on day two was the limitation of running the kit from the parallel port. There really aren’t that many computers these days that still roll out with a parallel port as standard, not to mention my nice shiny mac does not come equipped with a parallel port. I was 100% sure the solution to this problem was the trusty Arduino. There have been many projects where the Arduino has already been used as the heart of a CNC machine, the first that comes to mind is the REPRAP. There is also another CNC project called Contraptor which utilises the Arduino at its heart. The home site for the Contraptor project has a lot of useful information, it was there I came across Grbl.

I tried the RepRap g code interpreter, fiveD but I could not get it to compile for the Arduino (Any tips would be gratefully recieved). I also tried a few other interpreters with varying success: teapot, rsteppercontrol and arduino-gcode-interpreter-new. I really struggled, probably partly due to my lack of understanding when it comes to g-code. I had no success over the three days of training but I did find Grbl though I didn’t have the kit to test it. Grbl seemed like a very simple solution but the main hurdle when it comes to implementing it is that you need to use avrdude to flash it to the Arduino you can’t just send it via usb direct to the Arduino. I have never done this before so I let the Arduino rest for the the remainder of the training with a mind to try it as soon as possible.

Today I started messing around with Flashing Grbl to the Arduino and was caught out by several issues which slowed my progress. There are already several sites with information on how to do this but I found I needed bits from all my sources to get the job done. I thought I would document my process in case anyone else finds it useful.

First off the sites that proved to be most useful:

http://www.sparkfun.com/tutorials/247

http://www.arduino.cc/en/Hacking/Bootloader

http://dank.bengler.no/-/page/show/5471_gettinggrbl

I started by downloading the prebuilt hex files for Grbl here

I then downloaded Crosspack-AVR from here which installs a version of AVRDUDE (used to handle flashing the data to the Arduino)

The Arduino that is going to act as a programmer needs to have the programming firmware uploaded to it. This is a very simple task as it is all built into the Arduino IDE. Open up the Arduino IDE then go to File -> examples -> Arduino ISP then upload the sketch to the Arduino. The Arduino is now fully setup to Flash another Arduino.

The next step was to wire one Arduino to another to use as a programmer. I found the wiring diagram from Sparkfun here and the picture below is my version of the wiring. One thing that sparkfun didn’t explain is that you must disable  auto reset on serial connection. I found out how to do this here. I could not find a cable to suit so unfortunately I had to solder directly to the ISCP headers (not pretty).

Wiring for flashing the arduino

Now all the setup is done it is time to put AVRDUDE to work, on a Mac this is done via terminal.

I found the terminal commands for AVRDUDE on sparkfun here about half way down the page.

command one (make sure the Arduino is ready for grbl):

avrdude -P /dev/tty.usbserial-A9007VP6 -b 19200 -c avrisp -p m328p -v -e -U efuse:w:0x05:m -U hfuse:w:0xD6:m -U lfuse:w:0xFF:m

change the red text for the name of the serial port that your Arduino is plugged into

command two (load Grbl):

avrdude -P /dev/tty.usbserial-A9007VP6 -b 19200 -c avrisp -p m328p -v -e -U flash:w:grbl.hex -U lock:w:0x0F:m

blue text is for the location of the grbl hex file on the computer

Hopefully thats it, Grbl is now installed!

If you want to test that Grbl is working properly the you can download CoolTerm which is a GUI for mac for sending and receiving information on serial ports.

I come from an art/design background but sometimes I wish I had some training as an engineer. So many of my past projects would have benefited by a little extra knowledge. I have bodged rickety frame work from doweling and 2×2 hacked up sheets of metal to make mechanism, all the time thinking there must be a better way. I have often thought how awesome it would be to own a laser cuter so i could bash out prototypes to my hearts content. Unfortunately I don’t have the sort of money that it takes to acquire this sort of equipment. I am slowly getting my knowledge or engineering resource to a higher standard but it is very slow progress. I came across MicroMax today and it looks very interesting so I thought I would paste it up here incase it can help anyone else. The material looks awesome for rapid prototyping small projects that need accurate and strong frameworks. The website can be found here

I recently visited the ICA to see an art installation produced by Luke Jerram. Dream Director is a very interesting investigation into the realms of sleep and dreaming. The work builds upon work already out by psychologist Chris Alford at University of west England.

I am particularly interested in the technology around this project. People were invited to stay over night in a gallery theirs beds were custom designed pods.  Each pod was loaded with it own set of sounds and the sleeper was asked to wear an eye mask designed to measure rapid eye movements. As the sleeper entered the dream stage of sleep the different sounds stored in the pod were used to try and shape the way the person dreamed. In the morning everybody that took part in the investigation was asked to fill in a questionnaire about the dreams that occurred while they were in the pod. I thought this investigation/installation was very interesting. The exhibition is very worth visiting as the whole thing has been well documented with a documentary moving image piece screened at the ICA as well.

A little more info on sleep:

“rapid eye movements occurred periodically and in conjunction with a number of physiological changes. For example the brain waves exhibited low voltage and fast activity, and heart and pulse rates seemed to speed up. As Kleitman later described it, “These changes suggested some sort of emotional disturbance, such as might be caused by dream.”

quote and table found here

I would be very interested to know how the rapid eye movement detecting goggles are actually made if anybody out there knows!

To find out what else is on at the ICA go here

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