Alt-BEAM Archive
Message #08092
To: beam@sgiblab.sgi.com
From: "Travis D." beam_bot@yahoo.com
Date: Thu, 2 Dec 1999 15:14:08 -0800 (PST)
Subject: [alt-beam] Re: D'oh! Head Revelation
so is there an attached schematic? :-)
--- Wilf Rigter wrote:
> Brilliant Richard! and a good time resurrect the old
> servohead project.
>
> The attached schematic works with unmodified hobby
> servos and can be used
> with an umbilical connection to move the motor or
> the shaft with respect to
> the base. In first case the umbilical requires a 2
> conductor cable for power
> and in the second case, the cable is 3 conductors
> for the eyes. The power
> required for this circuit is a few ma but the servo
> continuously draws
> 50-100ma and more when stalled. A 74HC240 can be
> used instead of the 74HC04
> shown. In that case, up to 4 servos can be
> proportionally controlled with
> analog voltages from a photo bridge or other source
> like microcore outputs
> (hexapod), temperature (green house vent),
> differential sound level
> (security camera aiming), potentiometer ( 2 wire
> remote control), etc).
> <<...>>
>
> In the uCrawler V2.0, I did what you suggested and
> replaced the circuit
> inside the servo housing with the crawler circuit
> which also uses the servo
> pot (P1) for feed back to pump the crawler legs. As
> shown in the attached I
> changed the time constant from .3 ms to 30ms and
> that circuit will control a
> head exactly as you described but power efficiency
> is not great (ie similar
> to a bicore). A PS head version should be quite easy
> to do.
>
>
> <<...>>
>
>
>
> > -----Original Message-----
> > From: Richard Caudle [SMTP:rwcaudle@hpamonon.com]
> > Sent: Thursday, December 02, 1999 12:28 PM
> > To: BEAM
> > Subject: D'oh! Head Revelation
> >
> > Hey all,
> >
> > I just thought of something...I had proposed using
> a head controlled pot
> > to drive a +Phototropic robot body a couple of
> weeks ago. Inside of a R/C
> > servo is a gear train, positioning pot, circuitry,
> and a motor. The
> > driver circuit could be removed and a BiCORE (or
> PSH) circuit put in it's
> > place and the pot leads going out to the robot's
> body circuitry. The
> > whole thing could be housed in the box for the
> servo! The "eyes" are the
> > only thing that needs to move. Why mess with the
> weight of the entire
> > head. It dosen't have to go all the way around
> because it's mounted to a
> > mobile body. I have something like servos at home
> (gleaned from an old
> > "Teddy Ruxpin") and I'll give it a shot tonight,
> if I can find my
> > 74HC240. I left it right over there...
> >
> > Wondering Aimlessly,
> >
> > Richard
>
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8093 Thu, 02 Dec 1999 16:39:09 -0700 [alt-beam] New BEAM Tek mirror (was: beam tek website) beam@sgiblab.sgi.com "John A. deVries II" Well, the Heretics site now has an unofficial mirror of Mr. Bush's
wonderful BEAM Tek site. I'm using a web spider that is new to me so there
are undoubtedly dead links and other errors. Nonetheless, I'll try to keep
it reasonably current with Brian's. Hopably, http://www.serve.com/heretics
will be available at least as often (if not more) than the other machine --
in any case, there is now a copy if something catastrophic occurs.
Have a look, have a blast, whatever....
deVries
---------------------------------
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