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From: fredm@media.mit.edu (Fred G Martin)
Subject: Re: Crazy about legs
Message-ID: <1993Jan27.140858.29306@news.media.mit.edu>
Sender: news@news.media.mit.edu (USENET News System)
Organization: MIT Media Laboratory
References: <1993Jan27.043305.7387@sbcs.sunysb.edu>
Date: Wed, 27 Jan 1993 14:08:58 GMT
Lines: 25

In article <1993Jan27.043305.7387@sbcs.sunysb.edu> shane@cs.sunysb.edu
(Shane Bouslough) writes: 

>I've been thinking a lot about legs recently (don't we all? :-).
>If you're going to do a nice leg, say Brooksian, it seems like
>you'd need about one miniboard per. If you use 6 legs on your
>beastie, that's quite a few miniboards. Is that a good way to go?
>Or is something a bit more powerful a better idea?

In fact, this is just about what is done with Rod Brooks' robots:
there is a dedicated CPU per leg.  But, they use very small DIP CPU's
(maybe a 24-pin model), and surface mount motor controllers, so the
leg processor board is pretty small.  Also, it's kind of shaped like a
leg, long and skinny.

>Miniboards are such a nice "out of the box" solution, but a chain
>of them like that sure would suck down the juice.

The motor chips on the Mini Board are the "worst offenders"; they draw
about 30 mA each, even when not supplying power to a motor.  The CPU
itself only draws 20 mA.  If someone could find a more efficient motor
driver and paste it on to the Mini Board it wouldn't be too bad from a
power point of view.

	- Fred
