20 Jun

An hour or so drawing

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This is what happens when your .SVG export is set with incorrect settings. I left it running for a bit – I thought it looked interesting – also, no pen lift (the horn fell off the servo).

I was playing around with some simple ‘tween’ curves in Rhino / Grasshopper – hoping to increase my proficiency in GH to create some interesting vectors.

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The same drawing, with a slightly different home / start position. The red is a STABILO point 88, the magenta is a Pilot V5 Hi-Tecpoint Rollerball Pen Extra-Fine, and the blue is a Eye Micro Rollerball UB-150 (didn’t know that till I just hit up their website!) I knew there was a reason as to why I horde stationary.

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The green is a STABILO pointball, the nib is a little large and barely fit through the gondola nib guide thingy, so could have done with a larger hole for it to fit through.

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I ended up slowing the speed of the motor accel to a whopping 5 (seconds to max speed) and then I changed the max speed to 25 (half original value). A notable difference in both speed (slower) and resolution (straighter lines (but still not perfect)).

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27 Jul

Green Woodworking

Through our meetup group, Rob organised a Green Woodworking workshop with Toby from the Green Wood Work Shop! After a bunch of emails, we finally found ourselves wandering through the Purbeck woods trying to find the place, only 40 mins late we could hear the banter and see the smoke rising from the charcoal  burners. We were greeted by Toby and his dog, and a couple of the guys that made it, some as far away as South Africa! (I jest, he lived nearer London!)

Fortunately being late wasn’t that much a problem, I quickly followed what the other guys had started and found myself introduced to wooden mallets, lumps of wood (turns out it was Ash) and hand axes, some heavier than others! We had a few options of what we could make, from rounders bats, garden dibbers, to spatulas.

Some images from the day:

The space

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The rather rudimental work holder / lathe

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The axes had flat faces on one side, and chamfers on the other, this helped them bite into the wood. Some had both sides sharpened, some had short handles, some had long.

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Some rolling pins, a dibber and spatula, some having aged better than others.

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Forget what this is called – but it makes the stock as smooth / round as possible before heading to the lathe.

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Using a gouge to make a mark for the poppet to be located. I thought the poppet (work holder screw thing’ was a funny name, but we still say, ‘pop it in’ – don’t we?

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Guide on using the roughing gouge

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workin’ it

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Tools of the trade

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The beginnings of a rounders bat

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venting the hardships of motherhood into this bat

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This was a tricky tool to get to grips with, it gave a smooth flat finish, but any lapse in concentration and you’d put a lovely gash in it!

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Lots of these on the ground – how many dibbers have been made here?

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Rushed this – took about 1.5 hours start to finish – broke a sweat!

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Unfortunately I didn’t get a snap of everyone’s finished work! Maybe ill update if I can get copies.

Thanks to Rob for organising the day and Toby for hosting (also, to his mum for the food and cake!)

Was a great day out – I think the potters wheel will be next on the list!

 

26 May

New build

I fancied making my own VPIP based V plotter – and made some very minor alterations to the cad data (plastic parts) in the process.

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Just some of the parts required to build the thing – dog optional.

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The plastic parts for the build. Printed on my Mini Kossel in el cheapo blue via amazon @0.2mm layer height.

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The first job was to deburr the parts that required it – note the colour change depending on light conditions! The below image is a truer representation of the actual parts.

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Bashing the pulley thingies onto the motor shafts

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Followed by mounting the motors.

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And what is potentially the coolest part of the project (IMHO) is a swappable thing that allows for the pen nib to be stabilised. I have a couple of these with different diameter holes for the different sized pen nibs, eg a sharpie. This should keep the pen at 90 degrees to the paper and not move around inside the gondola. It just needs a deburr in the below image.

And as usual, I got carried away building the thing to carry on taking photos…

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Firstly I extended the mounting brackets for the motors – this will allow me to position the endstop encoders later down the line.

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These are v1 of the endstop thingies – they will protrude fromt eh front of the machine, but its really the only way I could get it to work ATM. It has Z adjustment with the M3 screw and two captive nuts, and Y adjustment of up to 10mm – having not used these before – hopefully this will give plenty of adjustment to the ball string on the machines.

I reduced the diameter of the gondola so it would print on my mini Kossel (160mm). I also added another screw mounting to hold all the components together.

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I added a spacing for the bearing housing  – allowing the shaft to move freely as it was being constrained by the enclosed design, as you can see from the lovely image below  – grey bits are the recess!

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The weights now have their own printed mounting – V1 worked with a little filing, so V2 I’ll try and fix that!

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I finally got around to building the new Hat for the Pi, but that has a few teething problems at the mo – so currently its not moving.

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This also has its own electronics mount – but I forgot about the SD reader at the bottom of the Pi, so I had to hack away at it a bit! I aim to make a cover for the electronics at a later date.

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I added cable sleeve and that makes it look that little bit better – but the cheap DuPont connectors are utter crap and just pull apart without any prompting >:(.

So, hopefully the config for the UART will get sorted reasonably soon, so I can start drawing with this damn thing! Its been a fun build though, I hope the work on the plastic parts can result in some high res / fast drawings to be created – speaking of which, better get cracking with that!

Some of the beginnings of the drawings…

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02 May

V-Plotter in the library – part 4

Joseph Warin has continued to create some work for the plotters – this time using drawing inspiration from Alan Kitchen:

I was inspired by Alan Kitchen, his letterpress print technique and colour schemes.

The print today was just a test run on CMYK colour and how long it would take the machine to draw them. 

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26 Apr

Hanging V-Plotters at the Arts Uni – Part 3

We’re online! Check out the details of the event here!

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Gallery staff Joseph has been a great help – getting the machines plotting most mornings.  The above image is his work – the poster design for the exhibition realised using the machines, in the style of Norwegian Pixel.

Cheated the process here by plotting text (black fill) – so it renders it out at its most dense – perhaps we need to implement plotting vector in fills.

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Got the large machine fixed – changed the gear wheel on the right motor – just need to get some bad ass vectors in place.

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Multi layered image – black Hi-Techpoint 0.5 fine over Neon (magenta) Stabilo fine 0.4

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To get the plots completed at A2, I changed the pixel size from 3 to 10 – so the spiral is large. I then later dialled it back to 7. I think Changing the speed would also be helpful (slower) – will get the resolution of the spiral that much tighter.

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Colour change mid plot

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Drawing studio interior rendered with Norwegian Pixel

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19 Apr

Hanging V plotters at the Arts University Bournemouth – Part 2

After a lot of faffing, things breaking and some head scratching, the machines are all working as anticipated and we’re almost ready to start doing some drawings!

This post shows the result of running some calibration tests and some test drawings.

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The Pylargraph machine is finally plotting a graph of tweets for the chosen disaster related keywords. For some reason the code had defaulted to scaling all tweets to a height of 1mm. This produced straight lines which wasn’t very interesting. Now its producing interesting line graphs.

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Then we have a vPiP machine rendering a Vulcan bomber. The grid is the result of a test program that we use to check the machine is properly calibrated and will be drawing things where we think it should.

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And the large format landscape vPiP machine drawing a vector of the exploded view of the Gondola (the thing that holds the pen) that this machine uses. Again, the grid is drawn by a test program.

14 Apr

Hanging V plotters at the Arts University Bournemouth – Part1

Our trio of hanging V plotters at the AUB

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The machine on the left is running Pylargraph and is plotting a graph based on the number of twitter search results it gets back for a series of keywords related to the theme of disaster.

The two on the right are running vPiP (which produced the framed images).

We hope to get the large machine on the right plotting large format vector images.

21 Mar

Installing and configuring Pycupi

There has been some interest in Pycupi from the wider community so I figured an install/configuration guide might be handy.

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Tank Girl – v-plotter CMY (3 pass) Pycupi spiral arc render A2 Stabilo Point 88 Fineliner

First off this guide assumes you are using a configured Raspberry Pi that is running a recent version of Raspbian Jessie.

Prerequisites

Python should already be installed along with PySerial. However we still need the Pillow library for image processing.

From the command line run:

pip install Pillow

If that completes without error you can move on to the install.

Install

From the command line (and somewhere in your home directory) run

git clone https://github.com/brianinnes/pycupi.git

That will get Pycupi. Inside the Pycupi directory you will find an Arduino/Stepper directory which contains the firmware for the Eggbot/Spherebot/Polargraph controller. A Python directory which contains the core Pycupi program and test scripts. A testImages folder that contains a few images. And a wikiResources dir which contains stuff that lives on the wiki.

cd into the Pycupi/Python directory and run

python test1.py

which will probably throw an error complaining about the serial port. Thats ok, we needed to run this to have Pycupi create the default config. The default config lives in your users dir (/home/some_user/.polargraph/config.cfg). You will need to edit a few settings to match your machine before you can do any drawing.

Note: A semi-colon denotes a comment in the config file. Any line starting with a semi-colon will be ignored.

Under the [Polargraph] section, configure the following (any settings not mentioned here, which are present in the config should be left as default):

  • pensize – not currently implemented – will be ignored.
  • machinewidth – This should be set to the distance in mm between your pulleys.
  • machineheight – The physical height of you machine measured in mm from the centre of your pulleys.
  • mmperrev – The circumference of your pulleys (in mm) or how much chord or chain (in mm) is played out for each whole revolution of a pulley.
  • setsperrev – The number of steps your motors make in each whole revolution.
  • stepmultiplier – The step multiplier applied by your stepper drivers (Pycupi firmware defaults this to 8).
  • serialport – The serial port your stepper control board is attached to (/dev/ttyUSB0 on a RaspberryPi connected to the ‘Arduino Nano dual stepper board v2.1’).
  • motoraccel – A time value in seconds that determines how long it takes the motors to accelerate to their fastest speed.
  • motormaxspeed – The maximum speed the motors are allowed to move in mm/sec (needs confirmation).
  • penup & pendown – not currently implemented. Configuration angles for servo are set in the firmware.
  • homex – The home position in the (horizontal) x axis, measured in mm from the top left pulley. This position can be anywhere you like. Suggested value would be in the middle of your machine.
  • homey – The home position in the (vertical) y axis, measured in mm from the centre line of the pulleys (imaging a line drawn between the centre of the pulleys, homey will be some distance below this). This position can be anywhere you like. Suggested value would be 120mm down from the centre line, but will be dependant on your machine.

For a graphical representation of machine size measurements, see this post.

Under the [Paper] section you can define your paper size and its position.

An example A3 page would be as follows:

  • size = A3 – The name of the paper size.
  • width = 297 – Width in mm.
  • height = 420 – Height in mm.
  • posx = 175 – The position (in mm) from the left edge of your machine to the left edge of the paper.
  • posy = 240 – The position (in mm) from the top edge (centre line) of your machine to the top edge of the paper.
  • margin = 20 – A margin (in mm) around the edge of the paper where the machine will not draw (usually where you tape the paper to the machine). The specified margin will be applied on all sides of the page.
  • pixels = 3000 – The resolution for this paper in pixels.
  • rotate = false – If false the image is not rotated. If true the image will be rotated.

Under the screen section:

  • screenX = 5000 – The resolution the plot simulations will be. When generating simulations (bitmap images of a plot), you can specify a higher resolution that your final plot so you can see more detail to spot potential issues before running a plot.
  • showImage = false – not currently implemented.
  • saveImage = false – not currently implemented.

Now when you run

python test1.py

the machine should spring into life and draw a rectangle filled with smaller rectangles.

03 Jun

Polargraph/Eggbot/Spherebot Electronics v2.1

I’ve somehow managed to skip from v1 directly to v2.1 with the electronics for my Polargraph.

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With this version i’ve fixed the mistakes and gotchas from v1, rearranged the component layout and changed the Arduino pins used to make routing the PCB easier (no vias!). I’ve also added a connector for an SPI SD card module. I don’t know if I will be able to use the SD card as the current firmware for ATMega328 based Arduinos is pretty much maxed out as it is, but I want to have a go at understanding the firmware and seeing if I can make it any smaller. And if I can then it is better to have a connector on the board ready, than have to add it later.

I also considered adding a connector for an SPI LCD but that would be really optimistic that I can make room for all the required libs.

After blowing up several Arduino nanos that seem to have a problem coping with external power and USB power at the same time, I’ve added a jumper to enable/disable external power to the Arduino. With external power disconnected the Arduino is powered via USB.

Boards are being manufactured by iTead using their great PCB prototyping service.

I’m also working on a better Polargraph gondola that piviots around the pen and has a quick change pen holder so I can easily do colour changes. I’ll post an update when its all done.

29 Feb

Polargraphs

MakeBmth has manged to get 3 Polargraphs working! (Technically 2 v-plotters running the Polargraph.co.uk software and 1 running a Gocupi/Python mashup)

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The one on the left is running the Gocupi firmware and is being run with Pycupi a Python port/rewrite of the Gocupi ‘Go‘ control software.

The other two are running the Polargraph.co.uk  a1_server firmware variant modified to run on our electronics.

The one in the middle is running with Pylargraph which is a Python script to control the original firmware with the intention of plotting or graphing the result of a regular twitter search.

The other is running with the Polargraph.co.uk control software.

The various 3d printed parts are our own designs or modified versions of existing designs.

My own designs are available on github and thingiverse but not everything is finished.