Alt-BEAM Archive
Message #12570
To: beam@sgiblab.sgi.com
From: Ben Hitchcock beh01@uow.edu.au
Date: Mon, 27 Mar 2000 07:46:28 +1000 (EST)
Subject: [alt-beam] Re: hpv, FRED and something else :)
Hi,
> a few questions thou,
>
> regarding the fred circuit, would it be possible to place photoresistors
> or a similar circuit in series with the fled? i'm rusty here, but i'm
> hoping that it would sort of tune the circuit a bit, thus, making the
> task of finding matching FLEDs less critical..not to mention better
> light seeking capabilities.:P Ben, Wilf, how's that? i've tried using
> FLEDs as light sensors before.. sad to say, for my case, the bot's
> actions were eratic(sp??), seeking light as and when it pleases.
Dear Oh Dear. Your robot was trying to write "Hello there, Zulu" in the
dust on your desk, and you took its motion as 'erratic'. Tsk tsk tsk.
*grin*
You can add any light-sensitive components you like to the FRED circuit.
The way ANY photovore works is by essentially having two solar engines,
the characteristics of which are affected by light. That's it. You could
try replacing the 33k with a LDR, or put the LDR in series with the FLED.
IF you do the latter then the LDR will have to be on the opposite side to
the FLED it attaches to, I'm not too sure what effect the former would
have.
But it would have some effect, and the effect would be measurable.
Experiment! The nice thing about solar powered BEAM creations is that it
is almost impossible to let the smoke out, so you can't damage anything by
trying things out. Give it a go! The worst that you can do is learn
something - and isn't that a good thing?
Ben
12571 Sun, 26 Mar 2000 15:30:49 -0700 [alt-beam] Re: 2n2222 on H-bridge? beam@sgiblab.sgi.com Dave Hrynkiw At 12:45 AM 3/26/00 , Bruce Robinson wrote:
>Hey, Dave. How come Solarbotics only sells half the '2222 / '2907 pair?
>.
Yeah, yeah, yeah. Ok, it's on my "to-do" list, ok?
Regards,
Dave
---------------------------------------------------------------
"Um, no - that's H,R,Y,N,K,I,W. No, not K,I,U,U, K,I,_W_. Yes,
that's right. Yes, I know it looks like "HOCKYRINK." Yup, only
2 vowels. Pronounciation? _SMITH_".
http://www.solarbotics.com
12572 Sun, 26 Mar 2000 14:51:34 -0800 (PST) [alt-beam] Yahoo chat going on now! beam@sgiblab.sgi.com Max Inggal There's a chat going on in the BEAM robotics club on
yahoo. Addy right here:
http://www.clubs.yahoo.com/clubs/beamrobotics
__________________________________________________
Do You Yahoo!?
Talk to your friends online with Yahoo! Messenger.
http://im.yahoo.com
12573 Sun, 26 Mar 2000 15:14:57 -0800 [alt-beam] Re: 2nd post - Anyone please? - Reverser circuit drawn wrong?? "'beam@sgiblab.sgi.com'" Wilf Rigter
Oops, you are right Ken! The In2 and Out2 labels
http://www.beam-online.com/Robots/Circuits/circuits.html
of the second
reverser circuit controlled by pin 19 should be swapped. In this version of
the reverser layout the pins are shown facing down. The reverser requires
just two of each the four inverters controlled by pin 1 and 19 but the other
two cannot be used for anything other than something that is active in the
backup state ie a backup warning beeper or extra drive power or changing
time constants.
These circuits are so simple but still easy to trip over.
regards
wilf
> Ken Hill wrote:
> >
> > Regarding the 240 reverser circuit from the beam online site,
> > If appears that from the data sheet of the chip that the number
> > 2 inputs and outputs should actually be reversed on the drawing?
> > Those two bottom buffers run the other direction across the
> > chip don't they?
>
> I
12574 Mon, 27 Mar 2000 12:48:15 +1200 [alt-beam] New soalrised Powersmart Head beam@corp.sgi.com Justin
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Taking the extra-energy saving PSHead feature Wilf posted yesterday, and
throwing in my favourite SE, here is a solarised PSHead circuit that is
probably the most power-efficient yet, doesn't use a 1381 (In many
places (like here) they are not availible), and thus has a voltage
trigger that can be adjusted via resister or pot.
On the bad side, I have not tested this circuit, but I have confidence
it works. The possibility of my making a typo when creating the diagram
is probably the bigger risk :-)
While I've given the voltage trigger resistor values I know, they're on
the low end of the scale and the circuit is probably better on a higher
voltage solar panel with a higher trigger level. To raise the trigger
voltage, I'd suggest adding a diode (between pin 2 and the diode that
connects to pin 2), as I don't how low a resistance you'd need
otherwise, and you probably don't want to take it too low. Such is the
vague advice you get regarding an untested circuit :-)
If anyone tries it, I'd be interested to hear how it goes.
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12575 Sun, 26 Mar 2000 20:39:48 -0500 (EST) [alt-beam] JOEL HIRTLE beam@sgiblab.sgi.com jester96beam@iname.com Hey I had to format my PC and lost all my ICQ names and other BEAMish info. Joel can you please e-mail me your UIN (use jester96@iname.com, not this address)? Thanks. Also anyone else I had on my list.
PLEASE no one reply to this on the list as it's not really BEAM related (well only sorta)
Chris
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12576 Sun, 26 Mar 2000 17:40:49 -0800 [alt-beam] Re: 2 new bots beam@sgiblab.sgi.com Bruce Robinson StickG@aol.com wrote:
>
> That seems all well and good, but how do you implement an Nu
> exactly? is it attached in a loop with the Nv's or does it feed
> directly into the Nv itself?
You will not normally see an Nu in a loop of Nv's (although you can get
some interesting -- not necessarily useful -- results if you do). The
usual method is to have the Nu's modify the various bias points in a
loop of Nv's.
However, I was specifically refering to the case of a head circuit that
would guide a robot. Various sensors would be mounted on the head and
their outputs would go to a pair of Nu's (one for Left influence, one
for Right influence). The outputs of the Nu's would actually determine
which way the head pointed by influencing whatever head circuit you were
using.
The typical Nu consists of a resistor going from the input to the bias
point, with a capacitor from the bias point to GND (or to Vcc). A signal
has to be applied to the input for a period of time before the Nu
produces an output. You can create an Nu with multiple inputs by giving
each input its own resistor, often with different values. You can also
put a diode in series with each resistor to determine under what
conditions the input will have an effect. And you can have inhibitory
inputs that tend to cancel the effects of the other inputs. Thus,
whether an Nu fires or not depends on the combined effects of its
inputs.
Challenge: make a robot with a high survivability capability ... detect
people and avoid them.
Bruce
12577 Sun, 26 Mar 2000 21:36:41 EST [alt-beam] Sonor beam@sgiblab.sgi.com Meabadboy@aol.com Hi,
Found this webpage from a E-Mail on the Handy Board list ~ good article for
Sonor applications ~ BEAM???
Ultrasonic">http://www.seattlerobotics.org/encoder/may97/sonar2.html">Ultrasonic
s and Robotics
Steve
12578 Sun, 26 Mar 2000 20:46:04 -0600 [alt-beam] Sunday Nite Chat ..again! beam@sgiblab.sgi.com SG if anyone wants to chat I'm there now...
(I can't catch the early Sunday chats.)
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