Alt-BEAM Archive
Message #09453
To: beam@sgiblab.sgi.com
From: Toby503@aol.com
Date: Fri, 21 Jan 2000 18:11:46 EST
Subject: [alt-beam] Newbie here....
I am good at electronics having built a motion detector and a siren. Can
anyone give some good websites from where to start in BEAM; such as building
your first bot?
Rusty
This message will self destruct in ten seconds...........
9454 Fri, 21 Jan 2000 05:00:47 -0700 [alt-beam] Re: Newbie here.... beam@sgiblab.sgi.com Dave Hrynkiw At 04:11 PM 1/21/00 , Toby503@aol.com wrote:
>I am good at electronics having built a motion detector and a siren. Can
>anyone give some good websites from where to start in BEAM; such as building
>your first bot?
One way is to start from our "Links" sub-page, and go from there. I
particularly like Chiu Fang's photovore tutorial.
Regards,
Dave
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that's right. Yes, I know it looks like "HOCKYRINK." Yup, only
2 vowels. Pronounciation? _SMITH_".
http://www.solarbotics.com
9455 Fri, 21 Jan 2000 19:00:38 -0500 [alt-beam] Re: Battery/Solar Power beam@sgiblab.sgi.com "Sathe Dilip"
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
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When everything's coming your way, you're in the wrong lane.
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9456 Fri, 21 Jan 2000 17:44:10 -0800 [alt-beam] Order of bots? beam@sgiblab.sgi.com Ian Bushong I started BEAM about a year ago, beginning of 7th grade, and built a
sollerspeeder from Solarbotics. Until now I really haven't done much
with it because of school, band, sports, Science Olympiad etc. (you know
how it goes :) I am getting back into it, and I was wondering what order
of bots you guys recommend me building. From easiest/simplest to
hardest/complex. I think this will help me to understand the BEAM
concepts better; a little more info each time. I am guessing the next
project that would be best for me to build would be a photovore. What do
you think? And one more question: Do you think it is more beneficial to
build your own bots from scratch, or use kits?
Thank you for any help!
-Ian
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