Alt-BEAM Archive

Message #10378



To: beam@sgiblab.sgi.com
From: Brad Guillot mach50@netzero.com
Date: Thu, 17 Feb 2000 20:44:30 -0600
Subject: [alt-beam] Re: photodiodes


These are actually ldr's(light dependant resistors) it takes buying a
couple of packs to get a well matched pair, and they need to be shielded
from direct light to avoid a unessary current drain. FYI i don't belive
they can be swapped out for phototdiodes unless you are using them in a
photobridge configuration

ect.ect......

brad

BUDSCOTT@aol.com wrote:
>
> hmm, ya know what. probably. i did see CdS photoelectric diodes, or whatever
> those things are, frankly they just don't have quite the quaity and anolouge
> charecteristics of PIN photodiodes. Oh well, kind of a tangent, like i said
> radio shack will never live up to what a BEAMer needs. oops!
>
> -Spencer
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10379 Thu, 17 Feb 2000 22:14:00 EST [alt-beam] Re: beamland going's on... beam@sgiblab.sgi.com JVernonM@aol.com In a message dated 2/17/00 5:37:48 PM Eastern Standard Time, BUDSCOTT@aol.com
writes:

> i've been tryin to make, or find some kind of ball bearing casters for
> my projects.
Try tiny craft beads placed on paper clip frames. You can see examples on my
site and Bob Shannon's.

See ya,
Jim
http://www.geocities.com/SoHo/Exhibit/8281/beamart.html
ICQ# 55657870



10380 Thu, 17 Feb 2000 23:24:40 -0500 [alt-beam] Non-Beam Question and Rant alt-beam@egroups.com David Simmons Hi Folks,

This is not really BEAM related, but I could really use some help here. Until
recently my son has been quite happy with a 500ma 12v power supply we built
from a kit and/or batteries to power most of his projects. Recently, however,
the supply went belly up and his projects are getting more complex, ie
multiple 12v stepper motors, Op Amp circuits, BEAM, Robotic Arms, and so on.
With this in mind his grandfather bought him a 13.8v 3amp supply. This works
great for his stepper motor work, but he needs to limit the amps and drop the
Voltage to +9v, -9v and +5v, -5v. Does anyone have a simple circuit using the
7805, 7809, 7905, 7909 regulators? Can I use ceramic resisters to kill some of
the amps, so he stops blowing IC’s. He, of course, is really hoping to build
something to solve his problem rather then spend all his budget on different
power supplies.



Thank You,
David

BTW This next part is a personal rant, feel free to ignore it entirely.

In 1997 my son Kyle (then 6) was labelled a slow learner and I was told he
would never make it in the “normal class room” will his peers. At first I was
hurt, and scared, but then I got mad. The problem, as the teachers put it, was
with communication. His printing was very poor, reading was nearly impossible,
so we started working from the ground up. Every day for hours we worked. But
nothing seemed to get him started, it was frustrating. But one day the VCR
gave out, just died. Kyle wanted to take it apart, see what made it tick. I
sat with him, let him hack away at it with my tools.
He worked on the that VCR for a week, asking questions that I had no answer
to, he ripped out a small motor and got it running with a battery, still more
questions. So we started looking for answers. Books, Internet, anything we
could find. The VCR still sat in parts while we tried to find out how the
circuits worked, what made the motors start and stop. Then in the library one
day I was reading about learning disorders while Kyle flipped though a picture
book. The book talked about teaching a child to read using symbols in one
chapter and later on about using something a child is interested in to promote
learning. It was like a light bulb lighting up, we could use both.
We started with simple circuits, a battery, a switch, a lamp. I would draw
the circuit using standard symbols from a book and he would put the parts
together and make it work. He built parallel circuits, series circuits, and
gates, nor gates, anything I could find that could be build with switches and
lamps. Soon he was drawing the circuits on his own. His grades started to go
up in school.
Next we moved onto a breadboard and discrete components, then ICs and
soldering, and now Robots, especially BEAM. Robots Rising was like a defining
moment in his young life, his drive in everything has changed. He is now a C
or B Student, most of the time. A picture of his hero Mark T hangs over his
desk, looking down from under his big hat as Kyle solders his latest project
together. When it is done and working he holds it up as if he is really there
and says. “It works, it works. See it follows that light.” His first head is
working, and I mean the pun.

Thank You Mark T.



10381 Thu, 17 Feb 2000 22:34:06 -0600 Re: osciloscope William Cox
> It's nifty, but how do you measure a signal? What do you use, besides you
> mic.?
> -William
>
> ----- Original Message -----
> From: CyberBug
> To:
> Sent: Thursday, February 17, 2000 2:39 AM
> Subject: RE: osciloscope
>
>
> > I am sending a file which I got a few months ago, I don't remember the
> > address but I hope helps.
> > It's a digital osciloscope program for sound card input.
> >
> > ----- Original Message -----
> > From:
> > To:
> > Sent: Tuesday, February 15, 2000 6:43 AM
> > Subject: Re: osciloscope
> >
> >
> > > http://www.cs.tcd.ie/courses/baict/bac/jf/labs/scope/oscilloscope.html
> > > http://www3.ncsu.edu/ECE480/scope1.htm
> > >
> > > These are the only scope sites I have. Hope it helps.
> > > Blumojo13
> > >
> >
>
>

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