Alt-BEAM Archive

Message #08109



To: beam@sgiblab.sgi.com
From: Timothy Flytcher [mailto:flytch@hotmail.com]
Date: Fri, 3 Dec 1999 08:23:57 +0100
Subject: Re: solar cells...



>well...
>since you said to start with the simple,
>does the length of the Leads from the cell make a difference?
>the ones i have on the solar cells now are about three inches.

YES... remember electricity dose not travel through the wire but over it ...

so small diameter single strand wire has a high resistance...
try hever or multy stand wire...
Timothy...

______________________________________________________



8110 Fri, 3 Dec 1999 07:07:03 -0800 [alt-beam] Re: solar cells... "'beam@sgiblab.sgi.com'" Wilf Rigter
Getting a $10 multimeter from radioshack would solve many of your present
and future problems.

However here goes:

The shade from the solar cell probably makes the LED appear brighter. At
small dc currents there is no "skin effect" in conductors. Try adding
relatively long leads (ie 36 inch or whatever) to your LED so that you can
observe LED brightness with the same dark background condition when attached
to the 3 inch solar cell leads or directly to the cell contacts. Is the
brightness the same ? If yes , the 3" lead connections are good.

With a multimeter set to the ma range, check the photo current through the
3" leads and directly from the contacts : is it the same current? if yes the
lead connections are good. How much current? How much does a different light
source, angle, filter change the current? Set multimeter to voltage range:
How much open circuit voltage? How much under load? How fast is the cap
charging? Does it rise above the 1381 trip level?

get the idea?

Next: "The Scope"

enjoy

wilf

> -----Original Message-----
> From: SG [SMTP:Sparkyg@seark.net]
> Sent: Friday, December 03, 1999 10:12 PM
> To: beam@sgiblab.sgi.com
> Subject: solar cells...
>
> well...
> since you said to start with the simple,
> does the length of the Leads from the cell make a diffrence?
> the ones i have on the solar cells now are about three inches.
>
> the reason i ask is:
> i attached a LED to the cell's wire leads. It burned faintly.
> i attached the LED directly ONTO the cell's + & - outputs and the LED
> seemed to burn much brighter.
> (hard to tell since the cell was directly under a bright light)
> -Sparky



8111 Fri, 03 Dec 1999 13:52:27 -0500 [alt-beam] Non-BEAM snake robot beam@sgiblab.sgi.com "Peter A. Low" Two articles on a cool snakebot

http://www.snakerobots.com/

http://www.newscientist.com/ns/19991204/newsstory8.html



8112 Fri, 3 Dec 1999 14:42:14 -0600 [alt-beam] bicore or microcore? "Beam@Sgiblab. Sgi. Com" "Phillip A. Ryals" Hi everyone,

I was just thinking dangerously again, and I can't seem to remember...

Is it a bicore or microcore that will move motors seperately? By that I
mean, motor one moves, motor two moves, and so on. I have an idea, but it
would require a gap in between each movement long enough for gravity to take
effect.

I was thinking the bicore is the one I need, but just can't remember.


So with that in mind...

How could one adjust the time between movements? And is it possible to
chain those movements so that the first motor wouldn't start moving again
until the last motor finishes it's sequence? Am I getting into the
microcontroller area now?

If this is possible, I think it's easy to see some applications.

Thanks all,
phillip

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