Subject:
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Re: ReMix of LEGO NXT Starter Robot
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Newsgroups:
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lugnet.robotics.nxt
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Date:
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Mon, 15 Jan 2007 15:27:46 GMT
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Viewed:
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11385 times
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In lugnet.robotics.nxt, Don Wilcher wrote:
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I’ve just posted an entry on my blog http://www.family-science.net/Blog.htm
on a ReMix project using the LEGO NXT Starter Robot kit. I’m creating a PoC
(Proof Of Concept) bot that can measure distances using a “STRAIT LINE”
eRolling Tape. To see the PoC “Measurebot!” device I’ve provided a small video
clip on the blog as well. Also, I spliced a 6 pin header to the RJ12 cable via
soldering so I may have access to the ARM processor’s I/O pins for electronic
sensor and controls lab experiments and projects development as well.
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I am curious if you have tried measuring distance travelled simply by reading
back the NXT motor encoder values? You would need to calibrate your ‘bot so
that you know the ratio of encoder units to centimeters or inches travelled
(which would depend on the gearing and wheels used) but you should be able to
get a very reliable reading without using any external hardware. The demo robot
model is capable of very precise navigation-by-odometry, which leads me to
believe that you could measure distance traveled with very high accuracy using
this technique.
I was also wondering if you were aware of the
documentation that LEGO has
made available regarding the NXT, which will probably answer many of the
questions that you have regarding the control signals present on the NXT wires.
It would seem that the motors are controlled using digital command packets sent
over an I2C interface, and the actual motor control waveforms are generated
internally to the servo motor unit itself. The NXT connector also has two lines
that are basically RCX-compatible I/O lines. I could be wrong, but I think that
anything you might learn by attaching a scope to these control lines has already
been documented for you by LEGO.
Hope this helps!
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Message has 1 Reply:
 | | Re: ReMix of LEGO NXT Starter Robot
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| Hi Chris, (...) that is not quite right, there is an ATMEGA48 microcontroller insider the NXT Brick which generates the waveforms. It is connected to the main processor via an I2C-style interface. Besides that it also controls power to the NXT, (...) (17 years ago, 15-Jan-07, to lugnet.robotics.nxt)
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Message is in Reply To:
| | ReMix of LEGO NXT Starter Robot
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| Hi All, I've just posted an entry on my blog (URL) on a ReMix project using the LEGO NXT Starter Robot kit. I'm creating a PoC (Proof Of Concept) bot that can measure distances using a "STRAIT LINE" eRolling Tape. To see the PoC "Measurebot!" device (...) (17 years ago, 8-Jan-07, to lugnet.robotics.nxt)
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