Alt-BEAM Archive
Message #09464
To: beam@sgiblab.sgi.com
From: "Thomas Pilgaard" ascii@hum.auc.dk
Date: Sat, 22 Jan 2000 10:48:59 +0100
Subject: [alt-beam] SV: Battery/Solar Power
I've got an LM78 voltage regulator, regulating a 9V batt. to 5V.
Does anyone know of a similar component regulating to say 3V
Thankyou in advance,
Thomas Pilgaard
> Daniel Grace wrote:
>
> > How can you hook your bot up to batteries and have the
> > batteries accurately mimic solar panels? Besides
> > voltage, that is. Is all you need a current limiting
> > resistor,
>
> Yes, thats what you essentially do. Say you need to emulate a solar
> panel with 3V, 20 mA rating. You can use a 3 Volt supply & a series
> resistance to limit the current to 20 mA (for the capacitor - which is
> essentially a short at the beginning, the resistor value equals 3
> volts/20 mA = 150 Ohms.
>
> >and maybe a voltage divider? What about
> > less-than-perfect light conditions? Does the voltage
> > or current go down? Or both? By this I mean max
> > voltage and current, I know that drop in voltage
> > across something means drop in current, and vica
> > versa, but if I understand right, there is a maximum
> > of each you can pull from each solar panel.
>
> Yes, both voltage & (hence) the current) go down.
>
>
> > So in short, with a voltage divider (if needed) and a
> > current limiting resistor, does that ensure that a bot
> > running off of batteries will run off of a solar
> > panel, or is there more involved?
> >
>
> It should run OK depending on how accurately you are able to mimic the
> solar cell. This is of particular importance while dealing with
> different families of logic chips. BEAMers tend to operate these chips
> at the lower end of power supply specifications (say 3 volts). If you
> test your circuit at 3 volts (with battery+resistor) & it works OK,
> there is no guarantee that it will work with a solar cell rated at 3
> volts if the light conditions just bring down the voltage a few tens of
> mV below 3 volts & your particular chip happens to be a strict follower
> of specification tables.
>
> I hope this clarifies it a bit.
>
> Dilip
> ------------------------------------------------------------
> When everything's coming your way, you're in the wrong lane.
> ------------------------------------------------------------
>
9465 Sat, 22 Jan 2000 17:39:23 GMT [alt-beam] Re: Snow Walker beam@sgiblab.sgi.com "Mike Kulesza" >Just wanted to mention to you guys it was snowin>where I live this weekend
>and I finally got the chance
>to test my new bot Snow walker 1.0 . He's completely
>water proof. He can walk in snow up to 1" deep. Deep
>than that he really doesn't make mush progress. Also
>quick question has anyone else try to make a snowbot
>or some other water-proof walker?
I was considering that too... Can you sned pictures, specifications and
dimensions???? Hoe does he not sink or frive himself under the snow?
______________________________________________________
9466 Sat, 22 Jan 2000 13:02:49 -0600 [alt-beam] Re: Snow Walker beam@sgiblab.sgi.com CORBIT GIBERSON
Max Inggal wrote:
> I finally got the chance
> to test my new bot Snow walker 1.0 . He's completely
> water proof. He can walk in snow up to 1" deep.
Do you have any pics of that??
9467 Sun, 23 Jan 2000 03:54:09 -0600 [alt-beam] Re: Hexapod Beam Bots? beam@sgiblab.sgi.com SG Wilf's 3M3D circuit still looks really neat to me for this type of
application.
-Spark
At 08:14 PM 1/21/00 -0800, you wrote:
>Has anyone built a Hexapod based walker using a walker circuit? Would a
>standard 3 motor walker circuit work? I've got some extra servos laying
>around and I was thinking of making a hexapod out of em...
>
>Thanks
>
>
>
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