Sunday, March 23, 2008


. ________________ Sir Arthur___ (AP photo files.)

Linkage represents power, status, success of one sort or another. Of course this has always been the case, particularly in the animal world, but I suspect in the uni-verse at large as well.

That is how our brain becomes conscious, how memories evolve and how life flows in the eternal dance of chaos and order, the breathing that holds the secret of our own existence.

When I think about the present state of technology, in this world of social networking, global communication, interplanetary travel, WWW,VR, SL and all these some basic, some quite indispensable parts of the life on planet earth, I remember, from the billions of people, one, whose influence and vision, some would say aura, inspired the creation of so many things that now we take for granted.

A person that inspired, through his writings, a Tim Berners-Lee to invent the World Wide Web in 1989. Who in 1945, proposed the idea of communications satellites that could be based in geostationary orbits around our planet, an idea laughed about by the official science of the time. After all he was only a writer.

A writer for whom spacecraft, asteroids and even a dinosaur has been named. A writer whose ideas, that is, the ones that have not been realized yet, are still considered far fetched even today, the stuff of dreams or sci-fi.

His hundreds of books and thousands of short stories constitute a cloud, a cluster or galaxy of links, of neuronal connections, of firing synapses that influence the world and will continue to do so for perhaps millenia, since his ideas travel as we blog, beyond our solar system into the universe he so lucidly dreamed about.

Who is this great human, whose passing through has barely been noticed in obscure obituaries as if we had nothing lost ?

Perhaps we have not, since he gave us more than we can take in generations to come. Besides, as he himself, quoting Rudyard Kipling said:

If I have given you delight
By aught that I have done,
Let me lie quiet in that night
Which shall be yours anon:

And for that little, little span
The dead are borne in mind
Seek not to question other than
The books I leave behind.

._______________________ From The Appeal

Thank you Sir Arthur, the world can or could be a better place because of you.

Wednesday, March 12, 2008

Command and Control

The recent integration of the Make controller with Flash, its scripting language and image processing capabilities, solves many of the problems I was dealing with, from the choice of microcontroller to the controlling software.

The program currently reads the position of the performer on stage and even the distance from head to ground, all with only one cheap webcam as an input device. There is so much information that can be acquired through image analysis that effectively eliminates the need for a variety of sensors that I had planned to use.

The only limitation is the amount of servo ports in the controller. I will have to daisy-chain at least two, to handle all the servos I think I need.

The servo that supports the weight of the marionette most of the time needs much higher torque than the ones I have. I have not calculated the minimum torque yet, but need to do that ASAP to order it and start testing the software that Philip and I are designing. I am very excited and happy with the progress so far. At first I had my doubts that the solution he proposed would work, but now I see it can, and in a very simple and elegant way.

The two sizes of spools we currently use (5 and 8 cm diameter) happen to be just perfect to provide most of the travel that I need without using continuous rotation motors instead of standard servos. This simplifies programing. We found out by testing a variety of "identical" modified servo motors that the speed of rotation, given equal parameters, is quite different, which implies writing routines to address each one of them to synchronize, a royal pain!

The fish-line spools with their bushings in place

The only continuous rotation motors I need are for the arms since they travel a much greater distance.

What was I thinking...

Just to finish the pulley rant, I created a template to drill the round wood pieces that I bought (99c/bag) at the local craft store. They seemed perfectly round in the bag...

Much to my surprise (am I new? or what!) they were far from round, I found out when I tried to fit them in my template. To make it short, I sanded them enough to fit, drilled and glued them together. As I was venting my frustration for not finding proper pulleys, my wife who works next to me in the studio, asked why I did not use the spools that she uses for her beading or the ones that I use for stringing (fish line) the marionette.


I must be very tired, been sleeping 4 hours max for months now. why didn't I think of the spools which were in front of me? So, here, I have a steady supply of the perfect size/weight spools.

I only needed to create bushings to adapt to the servos, real servos that is, not the modified ones by Vex which of course have a "proprietary" square shaft that only fits their kit stuff, I still cannot get over their lack of foresight and integration with the rest of the world. So much for Open Anything! Dean Kamen, you know much better than that!

I created the bushings with an aluminum rod that happened to have the right diameter.
I drilled the shaft hole to attach the Hi-Tech servos I will probably use, notched them to hold the adhesive better and epoxied them to the spools.

Saturday, March 08, 2008

patterns in the weather

A nonsense name for a nonsense week. I feel like I am under my own non-disclosure agreement since for my own protection I must keep quiet about a change in the weather. Can't see a safe haven yet...

So as it is true with all our daily activities, some things take precedence at the expense of our own life. And that to me is very expensive indeed.

On the banal but also symptomatic stage of the general deterioration of ethics and quality in our world and in particular where I live, I received a large package on the mail that I had no clue as to the contents, since I did not remember ordering anything as large...

Since I don't have a lathe or access to one at the moment I thought it would be easy to find the small pulleys that I urgently need for my project. As it happens, one of the most difficult things to find have been the pulleys or sheaves needed to raise and lower the marionette's articulations.

Why this is I don't understand. No robotic store or company, specially at the "hobby" or craft level carries such a useful and logic device. Can someone explain?

After much searching I finally found a place that purportedly had what I needed. Based on their description I bought 6 little sheaves to test. Here is what I got!

A ridiculously large box with 6 little pieces of crappy malformed plastic. Supposedly this place, whose motto is "Leaders in Education" wants to lead students, in step with the current government mandate to the lemmings paradise.

I imagine, they consider children or students simple ignorant people who do not deserve to touch anything decently made that might, just might teach them something. That way they learn to accept as a fact of life the terribly poor quality of life that education (with few exceptions) in this country provides to the millions, ground and trained through the system to accept mediocrity as the norm.

After all mediocrity and ignorance make good cannon fodder.

I ship the crafts I or my wife make all over the US and the rest of the world. One pound, Priority Mail costs $US 4.80 ...the shipping of these few ounces of bad plastic which cost US$ 1.50/each, cost US$ 7.oo for a total of US$ 16.00 I guess the huge box accounts for the "handling" fees.

I understand this post is a waste of everyone's time. But it is also part of the project. SO back to a more positive track I decided to build my own pulleys with wood. I will have to shape them with a sander given the lack of a lathe, but that will be OK.