Alt-BEAM Archive
Message #10805
To: beam@sgiblab.sgi.com
From: "FCO Enr." fco@total.net
Date: Thu, 24 Feb 2000 15:14:53 -0500
Subject: [alt-beam] Re: Combining Solar Cells
greetings Ben,
So I guess the BEST use for SCPD's is to boost voltage
and not current, due to the fact that their current output is so low.
But it's odd because I didn't notice the better low light charging
when I had the SCPDs in series. I was getting in ambient light
over 5v which I thought was great! But the current was so low that
it took VERY long to trigger. I am talking over 30 mins!!! I was
using a 2433 solarcell which had 16ma current but low voltage.
I figured I would use the SCPDs to boost voltage but I didn't
know that the current would drop to whatever the SCPDs were
outputting.
Now my next question is this, is there a way to split
the SE circuit so two seperate solar cell arrays are loading the
same Capacitor?
I think if I could use my 2433 (2.7v 16ma) with 10 SCPD's
in series ( 4v 1.4ma) then that would be excellent. But I am aware
this probably isn't possible. How about two SEs triggering the same
motors?
Thanks for your time and the schematic!
Andy
fco@total.net
hrdware's digital sanctuary - mindless oddities
http://www.angelfire.com/pq/hrdware
The Factory - TF Map Making Tutorial
http://www.planetfortress.com/factory
*********** REPLY SEPARATOR ***********
On 24/02/00, at 9:52 PM, Ben Hitchcock wrote:
>This is exactly the conundrum I faced with my Seaplane robot:
>
>http://wollongong.apana.org.au/~ben/seaplane/
>
>I used a 2911 solar cell, and I used two SCPD's to boost the voltage. So
>what's going on with your circuit?
>
>Well, the mini solar cells boost voltage, sure, but they HAVE A MAXIMUM
>CURRENT THROUGHPUT. This means that as soon as you start pushing too much
>current through them, they actually develop reverse voltage across them!
>
>So here's what to do:
>
>Put all ten SCPD's in parallel. Now attach the common negative terminal=
of
>this SCPD bank to the positive terminal of your SC2433. Now you should=
have
>an extra 0.45 volts to charge your solar engine with! That is, the=
voltage
>of the SC2433 + 0.45 volts.
>
>I did this with two SCPD's on my Seaplane because I wasn't too concerned
>with how long it would take to charge, but I did want good low light
>performance. I would suspect that your ten SCPD's in parallel will boost
>your performance a lot. I did notice that the maximum rate of firing=
slowed
>from 3 times a second to once a second when I added the two SCPD's (This=
is
>just like you described). But the low light performance is a lot better.
>
>Have a look at the schematic (attached) to see how I did it, and in your
>case I would just keep adding solar cells in parallel with the two that I
>have shown in my diagram.
>
>You could also make two lots of five SCPD's, and put each bank of five in
>series with each other and the Solar panel to give you an extra 0.9 volts.
>This will boost your low light performance more, but you will pay for it=
in
>terms of longer charging time in bright light.
>
>It's always a tradeoff, isn't it?
>
>Ben
>
>----------
>>From: "FCO Enr."
>>To: beam@sgiblab.sgi.com
>>Subject: Combining Solar Cells
>>Date: Thu, 24 Feb 2000 20:23
>>
>
>> greetings,
>>
>> Well I've been experimenting with my 1381 SE and
>> trying to figure out how to boost it's energy gathering capability.
>> My idea was to use 10 SCPDs and a SC2433 together to make
>> a solarengine that could work quite actively under my normal
>> room lighting.
>>
>> I did a few tests, wiring the 10 SCPDs in series WITH
>> the SC2433 under my regular lighting produced a pin to pin
>> voltage of 5+v, but when I wired it to the SE circuit and monitored
>> the circuit voltage, I was seeing a super slow increase in voltage.
>> When I removed the 10 SCPDs I noticed it was charging FASTER!
>>
>> So then I tried using the SC2433 in parallel with the 10 SCPDs
>> wired in parallel I noticed everytime I connected the 10 SCPDs into the
>> loop whatever circuit voltage I had dropped to aprox 0.45 volts and
>> it stayed there!
>>
>> I looked through my electronics theory book but I didn't
>> see any mention of such wiring and so I don't know what could
>> possibly be wrong.
>>
>> I would appreciate any help, especially theoretical info
>> that could help me put it into perspective.
>>
>> thank you for your time!
>>
>> Andy
>> fco@total.net
>>
>> hrdware's digital sanctuary - mindless oddities
>> http://www.angelfire.com/pq/hrdware
>>
>> The Factory - TF Map Making Tutorial
>> http://www.planetfortress.com/factory
10806 Thu, 24 Feb 2000 15:55:18 EST [alt-beam] Cheap calculator cells beam@sgiblab.sgi.com BUDSCOTT@aol.com now i recall on somebody's web site that some cheap calculators, 4-5 bucks,
have decent enough solar cells for BEAM applications, can anybody verify this
suspicion, before i waste money to destroy a calculator. thx
-Spencer
10807 Thu, 24 Feb 2000 15:53:39 EST [alt-beam] Re: Walker Legs beam@sgiblab.sgi.com BUDSCOTT@aol.com i'm finally finished making the frame, and boy is it something else. it
consist of a typical four AA battery clip with four NiCd rechargables in it.
the batteries face up, on the underside, i used two aluminum strips, bout 1in
x 1/16in x however long they needed to be. the front strip angles up at about
a 35 degree angle, i used nylon hose clamps and electrical tape and mounted
those wierd motors to the strips with a couple of size 8 screws now i plan on
usin a perf board to make a nice foax PCB, and mount the bicore on the
bottom, i also found a cool switch to use of on/off (not BEAM at all). i'm
gonna try that terminal block idea for mounting on some temp legs, once i'm
familiar with the mechanics of the walker, i plan on creating some heavy duty
non-wire legs, like some kind of thick beam type of stuff, i'll have to go
hardware huntin, but it oughta turn out prretty cool. thanks for all the help
your ideas, couldn't have even started without this lists help!
-Spencer
10808 Thu, 24 Feb 2000 13:12:38 -0800 [alt-beam] BEAMLAND and Solarbotics bring you 'Bot of the Week'... "'beam@sgiblab.sgi.com'" "Feser, Jason" Greetings List
Dave Hrynkiw and I have teamed up to create a new ongoing BEAM contest of
sorts. As suggested on the list, I'll be hosting a 'Bot of the Week'
contest on BEAMLAND. Everyone is invited to send in their bots which will
be placed in the BEAMLAND Webcam RJP to do battle with other contenders. At
the end of every week (Sunday) a winner will be decided by peer voting
(thats you guys) by way of a quick survey, and the winning bot will be
featured on the BEAMLAND Bot of the Week page along with an interview of the
winning designer and specs about the bot. The winning bot will keep
returning to the weekly contest until it either wins three weeks in a row
(an instant win), or we have four winners running around. At this point we
will have a vote for Bot of the Month, and a prize will be awarded. Prizes
will include goodies from Solarbotics including but not limited to Solarcell
assortment packs, 1381 packs and various types of motors. I'll also be
lining up some goodness in the form of Electronic Arts games and swag like
NHL2000, Ultima Acension, FinalFantasy 8, shirts, hats etc...
The success of this contest depends on your willingness to send in your
bots (which will be returned to the designer after it's stint in the ring)
and your willingness to get involved with the judging (voting) of the weekly
and monthly contests. It's still in the early stages and probably won't be
ready to go for at least a month or so, but I'd like to have some feedback
on how many of you would be interested in entering your bots in this kind of
contest...
Please reply privatly to me ASAP if you think its a good idea, or even
email me with any thoughts you might have so we can get this thing started.
Remember - if you don't send your bots, I'll win all the great prizes ;)
Jason Feser
BEAMLAND Robotics Division
http://members.xoom.com/jfeser
<http://members.xoom.com/jfeser>
P.S. As some of you noticed, the webcam is currently down due to an
unscheduled interruption of my cable. It will be back up on friday
evening...
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