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Subject: 
Re: NXT "remotes"
Newsgroups: 
lugnet.org.us.laflrc
Date: 
Mon, 31 Jul 2006 14:30:08 GMT
Viewed: 
1580 times
  
On Mon, July 31, 2006 9:05 am, John Brost wrote:
actually managed to get it to work rather quickly.  I was amazed at how easy it
was to create a receiver and transmitter program.  But I've got a few questions
for those of you who've done this sort of thing before.

1.  A "dead" spot in the center.  As it stands now, it is very tough to get the
transmitter back to "0" so the motors on the receiver NXT actually stop.  Is
there an easy way to create a larger "stop" zone?

I have mine set so if the reading is between -10 to +10, it stops.  So, if the
reading is <-10, go backwards, else if the reading is >+10 go forwards, else stop.

2.  This may be related to #1... I think I remember at HoB how at least one
remote was auto-centering.  How was that done?  Is it just a matter of
continuously driving the levers back to 0 degrees at a low power setting?

This is a bit tricky.  And, a bit of trickery.

The program is very simple.  The first command was: move motor A zero degrees,
followed by B & C.  Then, it went into the loop of transmitting the values from A, B
& C.  As long as the program is running, it uses full power to hold the motors in
position.

The remote I've been using is actually a very early prototype NXT.  That matters
because the original motors were not very powerful (unlike the production motors).

So, if you do this with a production NXT, it will drive the motors hard enough that
you can't move them.

What?  You say I should just turn down the power on the motor?  Sure, that sounds
good, however, I don't think it works.  The problem is that once the motors reach
their desired location (at low power), they get full power to maintain that
position.

I think you need to do the same type of thing that needs to be done for the
receiver.  So, if the Joystick rotation sensor is <-10, drive forward some distance.
If it's >10, drive backward.  Otherwise, coast.

Steve



Message has 1 Reply:
  Re: NXT "remotes"
 
(...) Thanks (and thanks to Bryan who replied off-lugnet) I had forgotten the bit about those motors being pre-prototypes. When I find time, I'll take a look at trying to figure out what to do with the more powerful ones. At the very least if I can (...) (18 years ago, 31-Jul-06, to lugnet.org.us.laflrc)

Message is in Reply To:
  NXT "remotes"
 
Things have been way too quiet on here for a long time now... Since I know I won't be getting much LEGO playing time at home anytime soon, and since I was headed out of town this past weekend, I took a page from Dave K's book and took my LEGO with (...) (18 years ago, 31-Jul-06, to lugnet.org.us.laflrc)

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