Subject:
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Re: Technic & robotics-compatible LEGO ZNAP clearance at TRU
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Newsgroups:
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lugnet.robotics
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Date:
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Fri, 28 Jul 2000 23:02:16 GMT
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Original-From:
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John Barnes <barnes@sensors{AvoidSpam}.com>
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Viewed:
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1162 times
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Hi !
Most of the tracks on larger toys have some form of stabilizing ribs or
studs on the inside surface of the tread. I simply use some tired Lego
technic wheels of an appropriate diameter in pairs spaced as required
for the width of the tread selected. The rubber tires give very good grip
on the inside surface of the tread.
As far as the booster is concerned, I built a MOSFET bridge amplifier
into a 2x4 brick with 2x4 electric plating on top and bottom. A wire
sticks out the side which goes to the RCX motor output. The brick's
4 MOSFETs duplicate the RCXs control, but directing the power from
the 9 volts battery pack instead. Gives slightly more voltage to the
motors, 9 instead of the RCX's 8 and is good to about 4 amps. So you
can easily drive multiple motors. The only limitation is the RCX's float
state which is not duplicated by my design. I have not found this to be
a problem. It is possible, but the resulting circuitry will not fit in a 2x4
brick and so I discarded it.
I think you can see it in my big-bot picture on my very amateurish web
page - www.borg.com/~pinkmice
The schematic is very simple. I can send details if anyone is interested.
But please note I'm away for ten days as of this afternoon, so if you email
me for more info, I may not be able to get back to you for a week or two.
JB
> Hello,
>
> > They don't work for me
> > and they're
> > too small. I have scavenged much large ones from Tonka dozers and other • large
> > scale tanks etc
> Can you tell us exactly which ones you used?
> How did you interface the "strange" treads with Lego?
>
> > they take more horse power too. So, using extra battery boxes like the one • in
> > 3591, you can easily build an RCX booster brick to run multiple motors in
> > parallel.
> How did you switch these battery packs? I can imagine that, if you just
> plugged the connectors of the batt. packs onto the connector of the motor
> and then connect the RCX to the motor, all commands coming from the RCX
> about start, stop, etc. would vanish in vain.
>
> Thanks
>
> Simon
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