Alt-BEAM Archive
Message #10679
To: beam@sgiblab.sgi.com
From: "Timothy Flytch" flytch@hotmail.com
Date: Tue, 22 Feb 2000 13:41:58 PST
Subject: [alt-beam] Re: BEAM: Tendency toward miniaturization
> >I can also see a deferent possible
> >future, or at least a faction... That is shoe box sized robots... small
> >enough to stay out of your way but big enough to do real yard work... to
> >walk over grass...
>
>take a look at my bot LOTUS..
>http://www3.telus.net/rfws/beam/sparky/index.html
>about the size of a shoebox! easy to build too!
>-Sparky
I Love your LOTUS... the problem is that it is "dumb"... We were speculating
on what the future will hold ... I know that the future hold some "smarts"
for this type of robot... now I'm not going to define "smart or dumb"
because I feel that hind sight will prove anything I could say wrong... But
I do strongly feel that LOTUS sized bot are a very PRACTICAL future... In
practical I mean like ... people have been buying and using gas powered
mowers for quite a wile... maybe robots will replace them??? This is just
one real, and practical use... (that and I hate to mowing the lawn...
allergies)
Why BEAM???
Well ...do you know how modern television was invented ??? It was by a
farmer... the problem was how do you make a picture appear on a screen...
there were several working models one had a spinning disc that changed speed
to change channels... but it was a hobbyist tech who was also a farmer was
out in his field plowing away on his tractor when it hit him... just like
rows in his field he could make lines on a screen... one line at a time then
just repeat... End result ... the monitor you are using now and all devices
like it...
I hope that the next advancements can come through Great people like on this
list who are openly sharing their labor and ideas with others... You just
never know when the next person may come along that will change the world...
And why do BEAM... one word... FUN :)
Timothy...
______________________________________________________
10680 Tue, 22 Feb 2000 16:43:44 EST [alt-beam] Re: Steering an Aquabot and giving it a purpose. beam@sgiblab.sgi.com JVernonM@aol.com In a message dated 2/22/00 2:36:20 PM Eastern Standard Time, fco@total.net
writes:
> Making sure it will always surface solar panels up :)
That one at least, is an easy one. Simply arrange the ballast so that floats
are on top and weights are on the bottom of the bots center of gravity. It
will right itself even if you place it upside down in the water. Proteus1
does this even though it is much wider than it is thick.
See ya,
Jim
http://www.geocities.com/SoHo/Exhibit/8281/beamart.html
ICQ# 55657870
10681 Tue, 22 Feb 2000 15:44:42 -0800 Re: Walker problems beam@sgiblab.sgi.com owner-beam@sgiblab.sgi.com [mailto:owner-beam@sgiblab.sgi.com]On
Hi,
> Well, I finally bought the RC servos for the walker the other day and for
> some reason, they are just don't work....once in a while, they might turn
a
> couple of times, then the gait becomes fully saturated and the motors
stop.
Sounds like you need a 0.1 uF cap across the power leads of the chip.
This should stop the saturation.
> The next thing that happens is that they just barely 'click' when they are
> suppose to be on, with not actual movement. I even stacked up to 4 of the
> 74HCT245's, but that didn't work either. (I couldn't get my hands on the
> 74HC245's...which might be the cause of the problem.)
This problem sounds like the servos are at the limits of their travel.
Once you gibve the bot legs, the servos should 'auto center', providing
you don't stack too many chips. Try centering the servos and seeing what
happens.
> Without the motor's,
> the circuit works great. With the cheap motors that I got surplus (just
for
> the sake of trying the circuit out), they work well with two of the
> 74HCT245's stacked. Now when I stick on the servo's, they just either
don't
> work, or they go into fully saturation and then they don't work. The
> servo's drink about 150 mA's, which should mean I could stack 3 or 4 of
the
> 245's and be in the clear by far. I am going to try to get some of the
> 74HC245's, (which I think have a wider range of input voltages.) The 7805
> didn't change anything, so I didn't try that for long. Any ideas on what I
> can do? Is it common for servos to use that much power? How many of the
> 245's can I stack? Is there something I can use that's not the 245, that
> can handle higher load? Is the H-bridge something I should be looking at?
> Take care and thanks in advance!
> Bernie
hth,
Ben
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