Alt-BEAM Archive
Message #11275
To: beam@sgiblab.sgi.com
From: Dave Hrynkiw dave@solarbotics.com
Date: Thu, 02 Mar 2000 17:06:59 -0700
Subject: [alt-beam] Re: 4+ motor walkers
At 04:19 PM 3/2/00 , Bumper314@aol.com wrote:
>Hello,
> For every suspended bicore walker I see it seems as though people choose
>to do the same old single bicore per 240 chip. What is the advantage of this
>over having 4 suspended bicores on one chip and just having a motor driver.
>Seems to me that you could cut the chip count in half for a 2 motor walker.
More motor driving power. Each gate contributes, what, about 50mA of
current sink/source ability to moving the motor. If you motors can work on
less power, YES, by all means split the '240!
-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
11276 Thu, 02 Mar 2000 16:52:26 -0700 [alt-beam] Re: Nice stryder! beam@sgiblab.sgi.com Dave Hrynkiw At 06:44 AM 3/2/00 , Dennison Bertram wrote:
>I had a few
>questions about your's. I know you said you ran into difficulty getting it
>to walk right.
.
.
.
>nk, now I relate it
>more to the noise you mentioned and lack of a 'clock' bicore) What do you
>think were the greatest problems in getting your Stryder to work? My feeling
>is that the robot itself is very complicated in terms of mecahincial design.
Mark jumps up and down about how the Stryder mechanics have to be
symmetrical in both planes (x and y). I don't doubt that, but I think that
the majority of the problems are with tuning the electronics. With even
skewed mechanics, I can tell that it's TRYING to walk, rather than throwing
an epileptic fit, and after that, a minor bend and tweak fix the mechanical
parameters.
>That's one reason why I was surprised at the leg orientation on your
>stryder. It's so hard to get things to measure up and be perfectly
>symmetrical.
Leg shape doesn't matter, as long as the foot contact points all measure
the same. Used graph paper to mark the geometry. And if I fold the front
legs full back, and rear legs full fwd, they just about meet in the middle,
heal-to-toe, so to speak.
> My third stryder was a succes I think inpart because I used a
>neat method for supporting the Motors at 30degree angles, (it is 30 degrees
>from the horizontal right)
30 deg from Horizontal? Sounds a bit extreme. Mine is 15 degrees of
vertical , a very steep angle. Is yours like this?:
___
\
\
\
\
Glad to share my Stryder experiences!
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
11277 Thu, 02 Mar 2000 17:05:39 -0700 [alt-beam] Re: Nice stryder! beam@sgiblab.sgi.com Dave Hrynkiw At 04:15 PM 3/2/00 , Bumper314@aol.com wrote:
>I agree, very nice stryder. Since you took off the head is it still
>phototropic.
Nope. Actually, I have the backup function installed, but no tactile
switches...yet. But no optic sensors.
>I have a pretty good idea of what the circuit could be, but
>would you mind posting it for the rest of us?
It's mostly on BEAM-ONLINE already. Ian built a Stryder Jr. too, but his
doesn't have the "pace-maker". I think there's better ways, but the way I
did it (which worked) is to set up a single pair of '240 gates in suspended
bicore mode, run the outputs to each of the master bicores inputs thru
resistors near the master oscillator value. So there's 4 resistors coming
off the 240; two to the front left master, and two to the front right
master. Do that help?
> What circuit would you suggest
>for charging batteries?
You're asking _ME_ after I admit I toasted mine?!? Sure, I'll tell you how
to kill them! ;> (as a rule trickle charge at ~15mA is VERY safe)
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
11278 Thu, 2 Mar 2000 17:04:25 -0700 [alt-beam] Re: Photovore Field of Vision "Flaming Headphones" Hi,
> a) make sure overhead light doesn't shine directly on the
> photodiodes (it often overwhelms them).
So even sunlight would overwhelm them, eh? So how much/what sort of
shielding would one use for this? Would a few layers of paper/thin card work
well? You still want it to see level though, right?
> b) turn them so they are not pointing parallel to each other. This
> will make your robot lock onto a bright light source more easily.
OK, so instead of having them point like....
V|-----|V
Where the open ends of the V's are the radiant sensetive areas of the
photodiode and the part in the middle is the rest of the bot
....You'd want them to point away from each other like
_| |-----| |_
Thanks for all the help,
Mike
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