Subject:
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6.270 vs. Handy Board motor stuff
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Fri, 22 Jan 1999 10:41:32 GMT
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Original-From:
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Richard Drushel <DRUSHEL@APK.ihatespamNET>
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Viewed:
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915 times
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[Max Davis] spake unto the ether:
> The motor driver chips (the TI SN75 ones) burn out pretty easily
> when I use the 6.270 motors. I don't know anything about the 6.270
> motors except that they come from Polaroid, but maybe because they
> were originally selected to run off of the 6-volt 6.270 board
> batteries (and through the 1.6 amp 6.270 board motor drivers rather
> than the 1 amp handyboard motor drivers), they draw too much current
> with the 9-volt handyboard batteries?
Too much current (and voltage) for those original
Polaroid motors, which are 6-volt.
> I notice that the motor driver chips on the Handyboard are not heat
> sinked in any way. Has anyone had experience heat sinking them?
I heat-sink mine with the clip-on variety; it helps.
> Has anyone tried stacking TI SN75whatever chips to get a better
> current rating? Do you think this would work?
I have done the 6.270 piggyback hack with the motor
driver chips from Handy Boards I got from Gleason Research.
This works fine. In fact, piggybacked motor driver chips from
my 6.270 boards work fine in the Handy Board. In fact, I
was about to suggest to Wanda Gleason that this "hack" be
made a purchasable option. Of course, since the Handy Board
is designed to be a 1-battery system, if you have motors
which use too much current, the internal battery won't last
long...so in conjunction with this, I have started to
modify my Handy Boards to take an external motor battery
(there is an input jack, you have to cut a trace on the board,
see the Handy Board FAQ for details; I have put a switch
across the cut so I can go back to the all-in-one configuration
if needed). In general, I prefer the 6.270 battery arrangement:
it's easier to swap in fresh cells and recharge later than have
to wait for the internal battery to recharge--the latter is not
an option in a contest situation where your operating time may
be an hour or more (as we do with our 6.270-based Egg Hunt).
Of course, your mileage may vary.
> Does anyone have suggestions for a good place to get other 9-volt
> motors (and cheaper than the lego motors)?
If you do the modification to accept an external motor
battery, you can keep using the 6-volt Polaroid motors you have.
I may be looking in the wrong places, but I see more 3-6 V motors
around than 9 V motors.
*Rich*
--
Richard F. Drushel, Ph.D. | "Aplysia californica" is your taxonomic
Department of Biology, Slug Division | nomenclature. / A slug, by any other
Case Western Reserve University | name, is still a slug by nature.
Cleveland, Ohio 44106-7080 U.S.A. | -- apologies to Data, "Ode to Spot"
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Message is in Reply To:
 | | (no subject)
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| Hello, folks. My first foray back onto the list in a few years. I checked the archives and didn't see an answer to this question, so here goes: Until recently, I taught a freshmen robotics seminar using old 6.270 boards, motors, and parts bought (...) (26 years ago, 21-Jan-99, to lugnet.robotics.handyboard)
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