Alt-BEAM Archive

Message #07123



To: Beam beam@corp.sgi.com
From: "Sathe Dilip" sathe_dilip@bah.com
Date: Thu, 28 Oct 1999 17:49:45 -0400
Subject: [alt-beam] Sharper Image butterflies


Last weekend, I was passing by a Sharper Image shop when I noticed some
electronic butterflies in the window. Curious to know if these were
based on Nitinol or something like a magbot, I took a quick look.

The butterfly wings are thin plastic cutouts. At the body/spine is a
clear plastic tube with some shiny cylinders inside. The wings are
attached to two of these cylinders. I think these cylinders are little
magnets. It looks like they are using a magnetic clutch like
arrangement. A magnet through magnetic coupling drives the magnet
coupled to the wing. I say this because a kid was forcing the wings up
& down once in a while but the wing operation did not seem to be
affected. Best part of the display is the slowness & smoothness of wing
flapping. There are no jerks. The butterfly is mounted on a rather
large box like structure which holds the circuitry, batteries etc.

It works on (IIRC 4) AA cells & is supposed to respond to sound. I did
not see a noticeable correlation between the sound & wing movement. May
be there is some adjustment for sensitivity. If nothing, we can
probably copy & use the drive mechanism in our butterfly like bots.
Next time, I will take a better look.

Dilip
--
Pl. remove *s from the e-mail address to reply



7124 Thu, 28 Oct 1999 18:57:51 EDT [alt-beam] Re: SolarPSHEADfest Part numbers beam@sgiblab.sgi.com Blumojo13@aol.com Thanks for helping.
Blumojo13



7125 Thu, 28 Oct 1999 18:58:51 EDT [alt-beam] Re: what is FYI??? beam@sgiblab.sgi.com Blumojo13@aol.com for your information
blumojo13



7126 Thu, 28 Oct 1999 20:01:04 EDT [alt-beam] Re: oscilloscopes beam@sgiblab.sgi.com Blumojo13@aol.com In a message dated 10/27/99 8:46:31 AM Pacific Daylight Time,
sathe_dilip@bah.com writes:

> www.cs.tcd.ie/courses/baict/bac/jf/labs/scope/index.html
>
thank you very,very,much!
blumojo13



7127 Fri, 29 Oct 1999 11:50:04 +1000 [alt-beam] Bicores...some technical questions Beam Mailing List Elmo Hi there everyone.

It been two weeks since i started out to build a Bicore Power Smart
Head. Over that time i have looked at many variations of bicore
circuits, and i have found myself asking all sorts of questions about
Bicores and mainly how and why they work. It seems that most beam
builders either dont understand the circuit or aren't sharing their
knoledge on the subject. So i thought i would post a few questions to
the list to see who knows what.

At this point i would like to ask people to respond even if they are not
sure their answer is correct. I sure as hell dont know whether my ideas
about Bicore operations are correct or not, but i would like to hear
peoples hunches about the circuit as much as any real facts. I base my
knowledge on the circuit on hunches and if enough people have the same
ideas about it then we can probably call that the most correct
explanation. So be be afraid to post any info.....


This is the basic bicore circuit that i am talking about (please excuse
my bad ascii art)

|---|>o---|
| \ |
= --r-- =
| \ |
|---o<|---|



So here's what i want to find out:

I am assuming that larger cap values in the basic bicore circuit
increase pulse width and smaller resistor values will increase the
frequency. Am i right?

Would it be better to have a circuit that has a fixed frequency and
variable pulse width or fixed pulse width and varible frequency?

Is it better to drive a bicore circuit at higher frequencies or lower
frequencies?

Is the resitance of the motor meant to affect the oscillation or pulse
width of the circuit?

Why are bicores built using high pass oscilators rather than then more
common low pass?

i.e. High pass -||---|>o- Low Pass -R---|>o-
| |
R =
| |
gnd gnd

Most people seem to add extra inverters into the baasic circuit to
increase the current output to the motors. Why do they add extra caps
into these parts of the circuits rather than just adding extra inverters
in paralell at the output of each of the main oscilating part of the
circuit?
e.g.

|---|---|>o---|---|
| | \ | |
= = --r-- = =
| | \ | |
|---|---o<|---|---|


Verses

|-|>o-|
|---|>o---|---|>o----|
| \ | |
= --r-- = |
| \ | M
|---o<|---| |
| |
|-------------|>o----|
|-|>o-|



Well than you all for your brain time. I would dearly love to make a web
page or three about the more technical aspects of Bicore operation so
that we all can hopefully understand our robots a bit better and maybe
confidently expand on other peoples circuits, backed with a good
grounding in why they chose their circuit desgin and componet values in
the first place


Thanks

Elmo

Home