Alt-BEAM Archive

Message #13404



To: beam@sgiblab.sgi.com, madhackers@egroups.com
From: SkavenArmy@cs.com
Date: Thu, 13 Apr 2000 20:25:35 EDT
Subject: i know this is a bit off the subject


But i need to find a proggie for winblowze 98 , or 95 or even red aht maybe=20=
,=20
that i can design my own computer. I dont need the schematic builder, but it=
=20
wouldnt hert. I need to be able to program it either in basic ,c++(or any c=20
compile-able "C"),html,perl,cgi,or even python. unix is also exceptable , bu=
t=20
im still working on my proggie skills for all . I need a graphical interface=
,=20
like a 3d imager (any or all of these are needed either in a single killer=20
package , or a bunch of little proggies that are what im looking for here or=
=20
there.=20

thanks
Jayz
aka
slide
aka
~^~][\/][=C5=D1=A9=DB=DF=B5=A7~^~



13405 Thu, 13 Apr 2000 20:48:40 -0400 Core-less walker beam Ben Hitchcock
> All,
>
> Yesterday I was toying with the idea of using the position of the feedback
> pot to tell the bot to stop turning the legs. After a couple of
iterations
> I realised that I could do away with the micro (or bi) core altogether,
and
> just use the position of the pot to tell the walker which way to turn its
> legs.
>
> I tested this circuit out today, and it appears to work. You have to use
> schmitt triggers as the sensing elements, and I had to use a 74HC245 to
> drive the motors themselves (a 74HC14 wasn't enough). This circuit will
> work with hobby servos quite well because they have a feedback pot to tell
> the driver what the position of the servo is.
>
> Problems with this circuit:
> If a leg gets stuck then bad luck. The circuit will stall. This is to do
> with the lack of timing elements in the circuit.
>
> Good points of this circuit:
> Simplicity of debugging: You don't need to debug a complex Pulse
> Neutralisation Circuit, or see how the process is walking around the core.
> Just plug the leads in and go.
> Simplicity of building: You don't need any more electronic elements than a
> 74HC14 and a 74HC245. NO other components are necessary (apart from
> batteries and wire)
> No leg stops: I dislike the idea of using mechanical stops to prevent my
> legs from going too far. This circuit does away with them altogether -
and
> your legs will NEVER go too far!
>
>
> I would recommend this circuit for people who want to get into walkers,
but
> are frightened by the complexity of a full-on microcore or bicore. About
> the only thing you can get wrong with this circuit is hooking up the
motors
> the wrong way - and then the only thing that happens is that the motor
goes
> to the end of its travel and stops. Reversing the leads makes them tick
> along nicely.
>
> Right now I have two servos alternating on my desk, just the way that
servos
> should if they were on a walker. I haven't actually tested this by adding
> legs and seeing if the thing moves, but it should work reasonably well.
>
> In the diagram I have omitted the 74HC245 driver for clarity. I regard
this
> circuit as a bit of a curiosity ("I did it because I can!") rather than a
> functioning piece of BEAM evolution such as the FRED.
>
> If anyone's interested in developing this further then an idea might be to
> use the remaining three inverters on the 74HC14 as a sort of 'getting
stuck'
> detector... if an output stays on for a long length of time then kick the
> input over the other way. I haven't drawn this yet because I like the
> simplicity of this drawing.
>
> Oh and another thing, to make the walker turn just bias one of the wipers
> either high or low with a 5 k resistor and the gait will change perfectly,
> not hitting any end stops or making the legs do cartwheels. Not bad,
eh?:-)
>
> Any questions, comments?
>
> Ben

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