Alt-BEAM Archive

Message #08266



To: beam@sgiblab.sgi.com
From: Bob Shannon bshannon@tiac.net
Date: Tue, 14 Dec 1999 19:35:51 -0500
Subject: [alt-beam] Re: Regarding Solar heads, such as Solarbotics model, and The tildens



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What you need to do, is recognise when you are in a 'good enough' light
pool.
If your solar cells are delivering maximum charge current to your
batteries then
looking for a 'better' location is a waste of energy and time.

In this condition, you know that the best behavior is to sit still, and
store energy.

Dennison Bertram wrote:

>
>
> Here's an Idea. Tilden say's that a robot should constantly
> look for better food. And while this is a good idea, what if
> it already happens to be in the brightest light pool? It
> doesn't make sense to leave. Sure it's not as interesting,
> but personally I've been on the side of the robots staying.
> Anyway, I used to be interseted in finding a way that a
> robot could tell if it was in the best source of light or
> not. I wasn't sure how to do this, thinking 'cds cells by
> the solarcell, some fancy circuitry?' well heres a
> simplified idea. Just use a solar head, that uses that new
> fancy stuff, I forget, 139 bridge, poppernets, or something?
> You know the one that blinks when it's "locked on". Well,
> instead of routing the outputs to one motor, route it to two
> so it's like a photovore, buzzing around looking for the
> brightest source of light. Then, once you find this source
> of light, the robot starts to blink to indiciate it's in the
> brightest light pool, and it aint moving. This would have
> several emergent behaviors, one of them would be, if another
> bot came by, and cast a shadow then the bot would very
> quickly move out of the way, avoiding the shadow. Flight
> behavior. Stuff like that. Anyway, someone should try it. I
> haven't studyed the poppernet (that's what it's called
> right?) circuitry for a few months so I'm a little rusty,
> and unsure about the conditions for a 'error' bit message on
> the 139. but it sounds feasible. dennison
>


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What you need to do, is recognise when you are in a 'good enough' light
pool.

If your solar cells are delivering maximum charge current to your batteries
then

looking for a 'better' location is a waste of energy and time.

In this condition, you know that the best behavior is to sit still,
and store energy.

Dennison Bertram wrote:

 
Here's
an Idea. Tilden say's that a robot should constantly look for better food.
And while this is a good idea, what if it already happens to be in the
brightest light pool? It doesn't make sense to leave. Sure it's not as
interesting, but personally I've been on the side of the robots staying.
Anyway, I used to be interseted in finding a way that a robot could tell
if it was in the best source of light or not. I wasn't sure how to do this,
thinking 'cds cells  by the solarcell, some fancy circuitry?' well
heres a simplified idea. Just use a solar head, that uses that new fancy
stuff, I forget, 139 bridge, poppernets, or something? You know the one
that blinks when it's "locked on". Well, instead of routing the outputs
to one motor, route it to two so it's like a photovore, buzzing around
looking for the brightest source of light. Then, once you find this source
of light, the robot starts to blink to indiciate it's in the brightest
light pool, and it aint moving. This would have several emergent behaviors,
one of them would be, if another bot came by, and cast a shadow then the
bot would very quickly move out of the way, avoiding the shadow. Flight
behavior. Stuff like that. Anyway, someone should try it. I haven't studyed
the poppernet (that's what it's called right?) circuitry for a few months
so I'm a little rusty, and unsure about the conditions for a 'error' bit
message on the 139. but it sounds feasible. 
class=860300616-14121999> class=860300616-14121999>dennison





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8267 Tue, 14 Dec 1999 19:41:36 -0500 [alt-beam] Re: Batteries beam@sgiblab.sgi.com Bob Shannon Zinc air is lighter (per milliamp hour) than just about everything, except
Li-Ion cells.

The problem with Zinc-air, is its volumetric efficiency (milliamp hours per
cubic volume) is very poor. Peak current delivery is also not great, due to
a higher internal impedance (Ni-MHD rules here).

For a park flier, if you want an unfair competitive advantage, I highly
reccomend
you use some 18650 series Li-Ion cells.

How about 4.4 amp hours in something about the size of a C cell, at less than
half the
weight of a C cell, and rechargable?? This level of performance is common with

modern Li-Ion cells, but the penalty is the charge control circuits, they are
highly
critical!

Timothy Flytcher wrote:

> I've only read about them.... But I would like to know more... Don't they
> just continue to degrade after instalment??? So use it all soon as
> opened???... I would like to build a R/C "parkflier" and 40% lighter sounds
> better... 40% lighter than what??? From what I've seen the guys are using
> lithium cells and getting 20-25 minuets flight time...
> Timothy...
>
> >Just wondering... anyone messed with Zinc-Air batteries? According to
> >what
> >I've read, they can be 40% lighter because they don't have to carry the
> >oxygen with them.
> >
> >I ordered one through work.. 8.4V. It comes in a vacuum sealed pouch with
> >the instructions "Do not open bag until battery is required for use."
> >
> >But from what I've read, they're supposed to be a lot longer lasting. I
> >know it's breaking off from the recharging thread, but thought it might
> >interest some..
>
> ______________________________________________________
>


8268 Tue, 14 Dec 1999 20:42:15 EST [alt-beam] Re: Bots for my b-day alt-beam@egroups.com TurtleTek@aol.com In a message dated 12/14/99 6:26:20 PM Central Standard Time, mutant@gate.net
writes:

> i received a Lego Mindstorm set today

Hey, on that topic, I was wondering if that stuff was any good. It looks a
little hokey to me but I've never tried it. More importantly, is that stuff
hackable? 8)

-Brien the TurtleTek



8269 Tue, 14 Dec 1999 21:27:16 -0500 Re: Batteries Jean auBois
> At 11:38 PM 12/13/99 -0500, you wrote:
> >In a message dated 12/13/99 8:25:48 PM Eastern Standard Time,
> >flytch@hotmail.com writes:
> >
> > > Hold up a minute Jim, are we talking about replacing the cap with a
nicad
> > > cell *or* charging the cell with the solar panel then the Ni-cad
battery
> > > charging a cap to run the engine???
> > >
> >Well, I was thinking of using a Pockmark, that is, a cap hooked in
parallel
> >with the solar cell (that's the Pockmark)
>
>
> Ooh aah! Someone actually using the name I came up with for
> something!
>
>
>
> Zoz
>
>
>

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