Subject:
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Re: mindstorms NXT
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Newsgroups:
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lugnet.robotics
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Date:
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Fri, 6 Jan 2006 17:45:37 GMT
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Viewed:
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7523 times
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In lugnet.robotics, Matthew Ruschmann wrote:
> Actually, the RCX outputs 0's and 1's to power the motors as it is right now.
> So all all you have to do is crimp your lego wires into a RJ11 and connect it to
> the NXT and send it a digital PWM signal. Voila! Your old motor works again.
I doubt that will do what you want. The RCX motor ports are equipped with motor
drivers - ICs that can provide rather a lot of current, switch direction, and
even short circuit the port. The digital wires would be I/O, not meant for
noticeable current, and only 1 or 0. So you'd wind up with an NXT shutting
itself off as the signal lines draw too much current.
No, what will be needed in the adapter will be such a motor driver, speaking the
appropriate serial protocol. Probably that means the device will contain a PIC
or PLC along with one or more motor drivers, and will be inefficient to build
for less than two motors per port. Personally I'm hoping for such a device with
separate power input.
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Message has 1 Reply:
 | | Re: mindstorms NXT
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| (...) I see no other wires into the motors, which means all the current is coming from that one connection. Whether or not there is separate supply and control lines in that connector is debatable until we get our hands on one - I would prefer not, (...) (18 years ago, 6-Jan-06, to lugnet.robotics)
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Message is in Reply To:
| | Re: mindstorms NXT
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| (...) Actually, the RCX outputs 0's and 1's to power the motors as it is right now. It uses Pulse Width Modulation (PWM). Basically for 1/3 power 1/3 of the pulse is 1 and the other 2/3 is 0. For full power, the signal is all 1. This creates a (...) (18 years ago, 5-Jan-06, to lugnet.robotics)
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