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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Thu, 5 Jan 2006 22:49:35 GMT
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Viewed:
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7467 times
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In lugnet.robotics, Ross Crawford wrote:
>
> Well, I hope they are also planning a smaller motor, without RPM sensor. I'm
> sure there will be many situations when I'm happy to sacrifice accuracy for
> size.
>
> ROSCO
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 non-linear input/output curve, but works.
http://www.restena.lu/convict/Jeunes/ultimate_stuff/speed.htm
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.
Of course, someone will have to build a block in "LabVIEW" to send the PWM
signal to the motor. Easy as pie if the software allows this.
Matthew C. Ruschmann
http://superpositioned.com
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Message has 2 Replies:
 | | Re: mindstorms NXT
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| (...) 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 (...) (18 years ago, 6-Jan-06, to lugnet.robotics)
| | | Re: mindstorms NXT
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| (...) I think that saying the RCX outputs 0's and 1's to the motor may be a bit misleading with respect to considerations of digital signalling. It is true that the CPU inside the RCX creates a logic level (1's and 0's) PWM signal intended for the (...) (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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| (...) Yeah it woulda been nice if the new one had IR as well and be able to control the "legacy" bricks. I'm sure the old ones will find a myriad of uses doing simpler jobs like moving cows heads on train layouts ;) (...) Well, I hope they are also (...) (18 years ago, 5-Jan-06, to lugnet.robotics)
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