Message #2980 - comp.robotics 
   Date: 09-24-92 18:44
   From: "Jonathan Mills"
     To: All (xpost: 1)
Subject:: Stiquito Files Fixed/ IP Number
-------------------------------------------------------------------------------
@PID: Fred 1.9.h
@MSGID: 1:124/2206.0 49e4981b
@Organization: Indiana University, Bloomington
@Message-ID: <1992Sep24.184451.6291@news.cs.indiana.edu>
@
Please accept my apologies for the file mixup.  The PostScript file is
now in the /pub directory but under a new name, and a UNIX-encoded
Microsoft Word 4 copy of the technical report has been added.

You can ftp in directly to the net address of cs.indiana.edu:

	129.79.254.191

There have been some connections broken due to timeouts.  I've split
and compressed the PostScript & raw Word 4 files, and will do the same
for the .hqx version if necessary. If you have problems with timeouts,
our net guru, Bruce Sheu, has kindly offered to help.  Send him mail
at shei@cs.indiana.edu.

To get the tech reports, connect using anonymous ftp.  The reports are
in /pub.  Set the ftp mode to binary to access the PostScript and raw
Word 4 files:

	stiquito.ps.aa.Z (restore with uncompress, cat)
	stiquito.ps.ab.Z
	stiquito.ps.ac.Z

	stiquito.w4.aa.Z (restore with uncompress, cat, uudecode
	stiquito.w4.ab.Z  to get a MacBinary Word 4 document)
	stiquito.w4.ac.Z


Here are answers to some questions on the report:

Does the robot walk autonomously using materials provided in the kit?

-No, but it is fairly easy to attach a small printed circuit board
 to the aluminum tubes that extend from the robot's back.  A draft
of Part 2 containing two transistorized oscillators controlled by
ECG 3034 phototransistors will be posted sooner than I'd expected, due
to these requests.  These circuits, and a 9-volt cell, turn Stiquito
into a legged Braitenburg photophilic or photophobic bug.

What is nitinol wire?

-Nitinol, sold under various tradenames (BioMetal, Flexinol) is an
almost-50-50 alloy of nickel and titanium that changes between two
crystalline structures as it is heated and cooled.  It can exert
useful force during the transitions, and make as many as 5,000,000
transitions before it ceases to work (maybe more).  Passing a current
through nitinol generates enough heat to cause it to contract.  A
spring or other force is necessary for the wire to expand back to its
original longer length when it cools.  Nitinol can be manufactured
in many shapes (eyeglasses, braces for teeth, etc.), but the cost
of special-forming is said to be high, how high I don't know.  The
wire costs $10 per meter from Dynalloy, Inc., Mondo-Tronics, & 
a few other manufacturers, but drops to $5.50 in 101 meter lengths.

The September-October issue of "Midnight Engineering" has a cover
photograph of a similar nitinol-propelled robot developed
independently by Roger Gilbertson of Mondo-Tronics.  I think that
Stiquito looks a little sleeker, but then I'm predjudiced! 

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