dorkbot bristol

People doing weird things with electricity - We meet every 3rd Tuesday

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Dorkbot at the Pervasive Media Studio, Tuesday 15th June

May 30th, 2010 · No Comments

The next Dorkbot meeting is on Tuesday 15th June at the Pervasive Media Studio.

We’ll probably take a summer break in July.

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Dorkbot at the Pervasive Media Studio, Tuesday 18th May

May 3rd, 2010 · No Comments

On the 18th May at the Pervasive Media Studio, Anton and Nat presented their “robot arm portrait artist”. It took a while to get it into the building.

John Honniball’s photos

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Notes On 20th April Meeting

April 21st, 2010 · No Comments

Some notes on yesterday evening’s Dorkbot Bristol meeting, for those who could not attend.

Ale Fernandez kindly took charge of the meeting in place of David Henshall, who’s stranded overseas by the volcanic ash cloud.

Rachel Carney started the evening off with the good news that our application for funding has been successful. This means that we have money available to make use of an otherwise vacant shop-front. There are some restrictions on the location of the shop, but we’re getting on with the search for a suitable one. Rachel also mentioned Scratch Day, which is on 22nd May this year, celebrating the Scratch programming language from MIT. It’s probably too soon to get anything ready for the shop-front, though. Rachel reminded us that this year is Dorkbot’s 10th anniversary, and it would be nice to make some contribution to that.

Richard Sewell mentioned our invitation to an art show under the Cumberland Basin road flyovers. It’s called Offerings To The Gods Of Speed, and takes place on the 19th of June.

I (John Honniball) did a demonstration of my work-in-progress on the idea of sending digital data by means of sound. This idea came from the Digital Voices project, based at the University of California at Irvine. That project aims to find ways for mobile computers to communicate using sounds that are both pleasing to the human ear and practical for data transfer. Some examples of sounds that the Digital Voices group are exploring are the R2-D2 robot sounds of Star Wars, synthetic bird song and synthetic cricket chirps. My interest was in the apparent complexity of the program used to decode the sounds, using a technique of DSP (Digital Signal Processing) called convolution. Convolution entails performing many multiply and add operations on digital data acquired from an analog source. My expectation was that a small, inexpensive computer such as the Arduino would be too slow to do such a CPU-intensive task. I was completely wrong, because my test program could comfortably detect eight separate audio tones in under 5milliseconds, much less than the 32ms that it took to acquire the audio data.

Richard Sewell had a much more complete demo of the Digital Voices work, with two Android mobile phones communicating using audible sounds. He had taken the original source code (in Java) and run it on the Google Android phones. He used the faster of the two phones to do the decoding of the signal, which is the more complex task. He was able to demonstrate sending short text messages from one phone to the other, using audio. This opened up a discussion on what the messages could be used for, how they might be broadcast, and what other types of computer could be used to receive them. We had all sorts of suggestions, including using the sounds as short-range audio beacons for positioning. Most people were in favour of making sounds in the style of The Clangers.

In last month’s Dorkbot, Richard Sewell showed us some parts that he’d designed and milled for a robotic walking mechanism. This month, he brought the complete radio-controlled crab-like walking robot. It has two motors, one on each side of the chassis, each driving the legs on that side. In the middle is the radio control receiver and the battery pack. The leg mechanism converts the rotation of the motors mechanically into straight-line motion of the feet.

There was a short break for refreshments and more playing with Richard’s walking robot. I took the opportunity to look at some videos of delta robots, which are a novel type of robot arm. Commercial examples include the ABB FlexPicker and the Adept Quattro.

Anton Bowers showed us his methods for making PCBs (Printed Circuit Boards) at home. He begins with an idea for a circuit, and develops that into a circuit diagram (schematic) in the Eagle CAD (Computer Aided Design) program. Eagle runs on Mac, Windows and Linux, and as a free version that, although restricted, is quite sufficient for home use. Once the circuit is finalised, he then begins the physical layout of the PCB, using Eagle’s board design mode. The final PCB design, showing just the copper areas of the board, is then printed onto transparent acetate or tracing paper. Anton uses UV (Ultra-Violet) sensitive copper-clad PCB material, and exposes it using a UV lamp box that he made himself. It only takes 45 seconds to expose the board, through the transparent artwork. He then develops the board in a plastic tank, and etches off the copper in another tank containing ferric chloride. This tank is heated using a modified aquarium heater and agitated with an aquarium air-pump. Finally, he drills the board using re-sharpened 0.8mm drills from the PCB industry. The final boards, although single-sided, are every bit as good as professionally-made boards, and much less expensive for small quantities.

Finally, as an example of the PCBs that Anton makes, he brought out his LED cube. This is a three-dimensional array of red/green LEDs, in a 4×4x4 cube. It’s connected to a shift register drive circuit (on another PCB), which is connected to an AVR ATMega32 microcontroller.

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Dorkbot at the Pervasive Media Studio, Tuesday 20th April

April 4th, 2010 · No Comments

This month’s meeting is a Dorkbot show-and-tell. Bring along anything you want to talk about. Chatting from 7.00pm, we probably won’t get to showing and telling until 8.00pm. Likely discussions are:

  • Digital Voices - getting devices to talk to each other audibly
  • Offerings to the Gods of Speed - exhibition under the flyover in Hotwells in June

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Dorkbot at the Pervasive Media Studio, Tuesday 23rd March

March 22nd, 2010 · No Comments

Just a quick reminder Dorkbot will be on tomorrow at the Pervasive Media Studio. We’ve contacted all the mailing lists we can find who are interested in Hackspaces. We’ll be starting the evening off at 7.00pm with an open discussion about Hackspaces. All invited. We’ll then move on to our usual Dorkbot show and tell session, this month covering Newcastle’s Maker Faire. If you have a project you’d like to show then please do bring it along.

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Dorkbot at the Watershed & the PMS 16th February

February 13th, 2010 · No Comments

This month Dorkbot will be starting off at the Watershed at 6.00pm. Here we can discuss hackspaces amongst Dorkbotters and the wider Bristol hacking, making, tinkering community. We can then move on to the PMS for about 7.00pm to continue hackspace talk and more show and tell.If you’d like to join in the discussion, have something to show and tell or would just like to come along and enjoy meeting up for Dorkbot it will be great if you can come along.hackspace-image.jpg

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Dorkbot at the PMS 19th January

January 16th, 2010 · No Comments

Dorkbot Bristol will be resuming our usual third Tuesday of the month meeting at the Pervasive Media Studio on the 19th of January.Bring along any project or topic you would like to talk about. We will also have a chance to see some more of the Dorkbot projects created for Uncraftevism at the Arnolfini and discuss ideas for what we’d like to do in 2010. We will be at the PMS from 7.00pm to 9.30pm.Look forward to seeing everyone on Tuesday.ales-pink-noise-machine.jpg

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Bristol Dorkbot invites you to Uncraftivism and the hall of eyes

November 25th, 2009 · No Comments

When confronted with the idea of a completely open slate Arnolfini exhibition, at it’s December “Uncraftivism” event, Bristol Dorkbotter’s eyes all flashed (and maybe darted around) simultaneously with the same idea, as if triggered by some kind of internal exhibition idea sensor that dorkbotters are all of course, modded with just after birth.

Many among the robot builders and tinkerers who gathered in our hackspace had for long years secretly harboured these deep urges to make rotating mechanical eyes that are able to follow an onlooker. Who wouldn’t, we asked ourselves? I myself, yours truly, had even imagined a pretend historical setting for these eyes, a legend that could somehow add depth to a gigantic mechanical eye installation.

Initial tests however, showed that no-way were we going to be able to produce a whole wall of them in the free time we had. They would look brilliant, but would all have to share the same movement, using pulleys or ingenious contraptions used commonly in animatronics.

We started discussing how they could be made without the usual system that powers moving eyeballs, i.e Servomechanisms, or - servos - which can be loud and jerky, as well as generally expensive both in energy consumption and parts cost. An interesting development came when Roboticist and puppet designer David McGoran realised you could move a small ball, held in place in some way, using only home made electromagnetic coils that push and pull a magnetic base around inside a sphere.

We now have two prototypes of this device, and more to come soon for sure. But the interesting thing about this of course is that if you have an idea for something you want to create or experiment with, Uncraftivism is a completely open exhibition, as explained in the detailed flyer for the event:

Create your event

For example, I will be using the Arnolfini’s Light room, (or Dark room?) to run some Ganzfeld Experiments using arduino based or DIY sensory deprivation machines. It’s part sound/light installation and experiment, and part fun brain hack and DIY gadget, which I hope you will be able to take home in some way or other. And lots of other people are joining in in many ways. According to the Arnolfini “Craftivism is a participative exhibition responding to the resurgent interest in craft as it relates to socially-engaged art practice”, so basically anything you make is a happy entrant.

Here is what the organiser Rui Guerra has to say about taking part in Craftivism’s satellite event, Uncraftivism:

unCraftivism is uncurated. Your work will not be judged, or restricted by a theme, nor does it have to be finished.”

  1.    Create a wiki page to document your event;  (Simply type the desired URL ex: )
  2.    Add your event to the program;  (Edit the online Program)
  3.    Announce it in your own network;

Hope to see you there!

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Dorkbot at the Pervasive Media Studio Tuesday 17th November

November 15th, 2009 · No Comments

Dorkbot will be returning  for its usual third Tuesday of the month meeting at the Pervasive Media Studio this week, 7.00 to 9.00pm

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May you live in interesting times day 1

October 23rd, 2009 · 3 Comments

Mini Maker Faire

So dorkbot have come to this fair country, or um, principality (not sure what Wales is these days?) to participate in the mini maker faire here in Cardiff.  We came with some Pisanomatic™ bikes. 4 of them to be precise, and they are now working, although the fourth is still soundless as it’s missing it’s crucial polystyrene, and hence, once the software is loaded on them, they will be missing a piece of the quartet.

There’s a huge variety of people here both visitors and stall people, some on the electronics side, doing circuit bending or LEDs, others stitching networks on cloth, playing google maps based routes as a melody or teaching people how to knit. A smoothie bike (by artist Carolyn Ryves who came to a dorkbot years ago, when it was in the Watershed) sits next to me humming as it blends, while John Honnibal whispers next to me - “it’s not sound, it needs a ball bearing”. Makes nice smoothies all the same though.

Unsound Smoothies

Sadly, the smoothie bike inventor is not here today so we can cross pollinate that idea. And cross pollination seems to be what is happening with lots of people, as has happened recently with Bristol Dorkbot participants, who have all recently, for example, discovered their mutual obsession with creating mechanical eyes whose stares can follow you around.

The GPS device sits outside in it’s missile-like metal piping pretending to be a WWII weapon, chained to the staircase and playing different melodies as different people move it around.

I’m also proud to show the table with our first product, the Bloktek Squeeeler, which we are selling for a fiver. I’m a bit less proud to admit that we only just located the soldering irons, and that instead of making one, I’m here writing this blog post.
Squeeelerz for sale
So I’ll go off now, hoping one of us will report back later on the performance of the Pisano bike orchestra later on in the car park. (by Ale)

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