Alt-BEAM Archive
Message #08716
To: beam@sgiblab.sgi.com
From: "Timothy Flytcher" flytch@hotmail.com
Date: Thu, 30 Dec 1999 22:58:52 PST
Subject: [alt-beam] Re: Carbon fiber, very dangerous and construction overkill + dont forget M
Ok... now it all depends on what you have and what you have experience
with... I have something for everyone to try... I have done this allot with
several models... using a tin can as a mold cover it with wax paper and lay
a pice of construction paper over it... carefully saturate the paper with
thin cyanoacrylate but don't let it puddle... just let it stand a few
seconds and presto... instant body shell :) trims with scissors ... sands
well... is flexible, light and strong... a strip folded at 90' and
impregnated thusly can make great legs arms or feelers... I have also made
some great bridges using sting with the same technique... It just doesn't
get simpler or cheaper...
Timothy...
HAPPY NEW YEAR :)
>My point exactly. And using woven mesh also depends on what tools you have
>to work with. I have a complete machine shop at hand. Some may not.
>
>CYA,
>
> Dane
>forget M
>
>
> > BS cowboy!
> >
> > The very thin carbon fiber rod is extremely light and strong for it's
> > mass... I feel it a superb frame material and quite easy to work with,
> > regular wire cutters work just fine - remember it's only 1mm diameter.
> >
> > If some of the more bitter sounding individuals out there deem it 'too
> > dangerous' or 'unnecessary overkill', then maybe it is not right for
>you...
> >
> > I have had excellent luck with it and use it all the time with great
> > success. Some of the designs would simply not be as efficient without
>such
> > a cheap, light, strong material.
> >
> > Expensive? try 4 feet of 1mm rod for $3.75!
> >
> > Please note, it's the ROD that i'm advocating, not the woven mesh -
>which
> > would be wonderful too, but MUCH more difficult to use.
> >
> > Why for such an interesting and creative hobby as this are there so many
> > people resistant to new ideas? Look how long it took the superior
> > chloroplast circuit to gain acceptance. weird.
> >
> > /Adam
>
>
>
______________________________________________________
8717 Thu, 30 Dec 1999 23:08:20 PST [alt-beam] Re: interesting robot address beam@sgiblab.sgi.com "Timothy Flytcher" It's really simple... The "arm" acts like a tail when extended to stabilize
the bot on the pitch axis... and pulled in winding the spring the bot
pitches back onto the tail then it is released ... flinging the bot up into
the air...
Timothy...
>Jim,
>It looks like it is a lever working in opposition to the motors. I can't
>figure out how the body doesn't turn with the wheels unless it is very
>heavy
>but that is the key I suppose.
>Rob
>
>Jim Taylor wrote:
>
> > Any ideas how that spring arm actually propells the bot off the ground?
> > James Taylor
>
______________________________________________________
8718 Thu, 30 Dec 1999 19:50:58 -0800 (PST) [alt-beam] Re: FLED schem beam@sgiblab.sgi.com Max Inggal Here is a segment of your circuit: (I have not shown the
solar cell, or the storage capacitor)
+ >-------o----------------.
| |
| |
M motor /
| |V
o--/\/\/\--o--| 2N3906
| 2K2 | |\
\ | \
\| | |
2N3904 |-------------'
/| |
V -
| V FLED
| -
| |
| o---< Max's
| | additional
G >--------o---------o---< connections
Okay, follow so far? The above is just the standard
FLED SolarEngine. This part works just fine. The
caveats for this circuit are recorded elsewhere: a) cover
the FLED, and b) use an efficient motor. You drew it
reflected on the right side for the second motor.
Here's where there are problems with the schematic Max.
The first problem is with the whiskers.
Equivalent circuits
from FLED switch open switch closed
|
o---< <---o----. <---o <---o
| | | | |
| | \ | |
| | \ | |
| | o | |
| | | | |
| | / | |
| | \ | |
| | / | |
| | \ | |
| | | | |
| | | | |
G >--o---< <---o----' <---o <---o
Do you see the problem? You've drawn a shunt around
the switch and resistor that prevent the switch and resistor
from having an effect on the remaining portion of the circuit.
This shunt is itself shunted by the connection to ground in
the first half of the circuit. This circuit segment does
not affect the FLED circuit.
The second problem is with the photodiodes. This circuit
segment is equivalent to the centre portion of your drawing.
I've removed the switches and resistors due to the shunt
explained above.
+ >---------.
|
V
,-\/\/\/-.
| |
- -
V PD1 V PD2
left - - right
bias | | bias
<----o o---->
| |
||
| |
G >---o--------o
The bias points are at ground. They can not affect the
FLED circuit. The only 'function' this segment has in your
schematic is to consume additional current.
Once we remove the non-functional segments of your circuit
we are left with two standard FLED SolarEngines attached to
one solar cell and storage capacitor, like so:
,---o------o------.
| | | |
--- | | |
- =C1 SE1 SE2
--- | | |
- | | |
| | | |
`---o------o------'
Unfortunately, this won't work reliably. The first SolarEngine
to fire will drain the storage capacitor and reset both
SolarEngines. If the FLEDs are very well matched, the photo
current generated by light falling on the PN junction might
affect the trigger point in a useful way.
The traditional method of building a photovore from two
SolarEngines is shown below (and elsewhere on the 'net)
,---o------. ,---o------.
| | | | | |
--- | | --- | |
- = FLED - = FLED
--- | SE1 --- | SE2
- | | - | |
| | | | | |
`---o------' `---o------'
So the SolarEngines are only connected mechanically. Adjust
the angle of the solar cells to demonstrate photo-philia vs.
-phobia.
If there are some other corrections to your schematic that
will demonstrate how it is that your photovore is working,
please let us know. I'm sure you see that there are others
interested in the design. If you circuit is reasonable and
original, other will build it and give you credit on their
web sites. If not, they'll probably try to nudge you in the
right direction.
Regards,
Richard.
Home