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AID: AID and the Orpheus Filter

From: Steven Wood   stevenikoro.com
Date: Fri, 15 Oct 2004 01:31:32 -0700

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Dear Mike, Stefan, et. al.:

I've still been lurking about the AID list and find myself in the
fortunate position of being able to contribute a substantial amount of
time to AID issues over the next month while simultaneously fulfilling
project objectives.  I am involved in coordinating an installation
project as part of the upcoming AIA/ACADIA conference on fabrication
[http://www.fabrication.ald.utoronto.ca/].  With a dedicated team of
four we are sprinting to produce the final product, and I would like
very much like to adopt AID as our interactive platform for this and
future iterations, provided it is far enough along.

Project Background
------------------
The installation, entitled Orpheus Filter, is a large interactive hybrid
fabric made of plexiglas geometric structural elements, a paper/mylar
'osmotic' membrane, and clusters of interactive 'whiskers'.  Formal
descriptions are better left to the photos:
http://ikoro.com/p/orpheusfilter/.

The proposed groupings of whiskers that hang from the fabric of
interconnected parts behave much like cilia.  Each whisker will be
simultaneously a sensing device and an actuator.  When the whisker
senses contact, subtle waves of motion propagate (using small motors at
the follicles) through the group.

The physical side of the installation is quite mature through two
previous iterations.  We are at the point of needing to settle on a
microprocessor platform to control the whiskers.  The demands of the
project on the scale of a single node are very simple: sense when a
whisker has been contacted, activate nearby motor circuits according to
some algorithm.  The challenge is the complexity of scale:  We need
control of somewhere between 100-200 whiskers in order to generate the
desired effect, implying that a series of controllers need to be somehow
together somehow.

Originally the project conceived using the Cricket devices developed at
the Media Lab [http://llk.media.mit.edu/projects/cricket/], however
Cricket has the limitation that multiple nodes can only communicate
using IrDA.  In our application, line of sight between nodes cannot be
guaranteed given the number of devices and the non-planar nature of the
fabric we are dealing with.  I would therefore like to migrate towards a
platform that has a hard-wired bus for networking controllers together.
(Not insignificant is the fact that a two-channel Cricket costs about
the same as the multi-channel AID.)

Now, it is difficult to determine just how far along the AID project is
from the documentation.  It seems like many of our desires fall into the
AID Level 2.  In evaluating whether AID is suitable for the project, I
am curious as to exactly what AID can do "today", and what development
we would need to plan for to reach our goal.

To that end, a few questions:
----------------------------

1) We may be interested in running the entire program on board.
Documentation says this is part of Level 2, and Mel Wilson makes mention
of this in  http://interaccess.org/aid/list/msg00740.html, citing
'pretty heavy programming'.  Could someone quantify 'pretty heavy' in
this context?  Would this change the hardware requirements, or is the
transition strictly firmware?

2) Assuming (1) is possible, would the bus be in a state where one AID
mainboard could send commands to several other mainboards?  I assume at
the very least some pinout and cabling changes would have to be made,
but are there deeper bus limitations that would limit the total number
of boards attached to such a bus?

3) Assuming (1) is possible, is it possible to upload user mode code to
AID using the serial port, or will we need to re-cook the chip in a PIC
programmer each time a change is made?

4) What is the greatest number of A/D channels available in one unit.  I
seem to remember the number was eight.  Can these be done directly on
board or is the analog breakout mentioned by Rob in
http://interaccess.org/aid/list/msg00687.html necessary?

5) Related to (4): How about total number of I/O channels if we go with
simpler open/close switch sensors and actuators?  This may be sufficient
if we reduce the current to the motors via hardware.

7) Related to (5): The motors we are prototyping with so far are very
small 1.3V 10mm pager motors.  Could these be run straight off the main
board logic power?  Rob mentions a motor driver board in
http://interaccess.org/aid/list/msg00694.html, and I see references to
it elsewhere also.  Is it complete?  Necessary?

8) Is there a current mainboard PCB image?  All links at
http://aid.interaccess.org/drupal/?q=book/view/17 are dead.

9) What is the break-even point in effort required for DIY etching vs.
using a blank board?  Pending the outcome of questions 1-8, we may want
to fabricate several of these.  If perhipheral I/O cards are needed
we'll wish to etch those onto the same PCB.

***

In short I need to get a sense of whether a solution using AID is within
grasp.  This is a great opportunity to develop a "worked solution" or
two in a very short timeframe, and we would certainly endeavour to
reflect as much of that development as possible back to the AID
community.

The last and most important question is, will the support be there when
we need it?  I realise AID is a volunteer project and the last thing I
wish to do is stress a community that has already contributed so much.
At the same time, I'd like to know that at least a couple of people
would be available to answer questions where necessary and that the
knowledge pool isn't completely unavailable this month.

I think this is a great chance for AID benefit from the resources we
have committed to our project, as well as exposure at this highly
regarded international forum.  It is also extremely likely that the
Orpheus Filter will continue to evolve in a manner that future
iterations will be able to both inform and apply refinements made to
AID.

Regards and thanks for your time if you've read this far, Steven

 =========================================
 Steven Wood
 IKORO Digital Inc        http://ikoro.com
 =========================================


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