can bricks be "linked"

[mikebittmann]

I'm very new to robots and Lego. My NXT kit will be arriving in a few days. Somewhere I read that a brick cannot control other bricks. I see pictures of robots that obviously have more than 3 servoes. I saw a picture of a large robot that seemed to have more than 3 bricks. How does this work?
Thanks, Mike

[mattallen37]

NXTs can communicate directly between each other using Bluetooth (slow wireless connection, with a limit of 4 NXTs) or RS485 (super fast wired connection, with a limit of 32 NXTs).

[inxt-generation]

Up to 4 NXT bricks can communicate via built-in BlueTooth in a Master-Slave configuration. You can also use the RS485 functionality of the 4th sensor port. However, while much faster, this requires the bricks to be wired together, and custom hubs/accesories to do it with more than 2 bricks.

EDIT: Ninja'd by Matt.

[mikebittmann]

That was quick, is the method of doing this via bluetooth covered in the lego nxg instructions?
Thanks again, Mike

[inxt-generation]

I don't know. The last and only time I used BlueTooth with NXT-G was nearly two years ago. IIRC, I found other peoples BlueTooth programs and figured out how they worked.

[mikebittmann]

My grandson received a new Mindstorm kit for christmas. We had a good time working on the robot together. He did all of the programming. I have never done any programming of any kind, but the tutorial I found on the net seemed pretty simple, for simple things. The more advanced stuff comes later. I already know that I want both the 8547 and 8527 kits. The 8547 is on the way.
Mike

[mcsummation]

Yes, the Bluetooth information is covered in the NXT-G, either with what's with the set or in the on-line documentation.

[tabbycatrobots]

Before buying both an 8527 and 8547, maybe check the 9797 at <http://www.legoeducation.us/>. It
has a little different assortment of parts.

[aswin0]

Doc,

You are perfectly right that the NXT communication is not error proof and that it never will be. However, you fail to comprehend that this is true for everything in real life. There is no fail proof communication, just as there is no car that can't break down, just as there is no plane that cannot crash, nor a ship that cannot sink. Everything in real life suffers from a thing called chaos!

So, how to deal with the NXT communication in specific and life in general? The thing is that you have to make it good enough for what you have in mind, to make it acceptable. And for a toy like the NXT, acceptable is different than for a plane carrying hundreds of passengers.
I, and others on this forum, have tried several times to help you to get an acceptable solution for your problems. But you only demand the perfect solution, not seeing that this is impossible. That's why I gave up to help you, and this is what I advise Matt to do as well.

I ask you to keep the acceptable in mind whenever you feel the urge to respond to someones questions. Ask him (or her) what kind of solution will do, before you spit out your negative opinion.


Aswin

[tabbycatrobots]

Regarding BT between NXTs, I've used it a lot on several projects. It does work for
me. With one limitation, I find it to be reliable. That limitation is connecting
multiple NXTs, in an area with dozens (hundreds) of people with cell phones. There is
just too much Blue tooth activity. This past New Year's eve, I demoed my robots at
an event in a large auditorium, with all kinds of electric equipment, electronics, music,
and lighting equipment, and 100s of persons, probably most with cell phones. When
I started a duet dance routine, the master always connected to the 2nd dancer. When
I tried to connect 4 robots for a dance routine, usually BT connection failed to one of the
three support dancers. In my house, connecting 4 robots is very reliable. There are some
limitations, as to how fast you can send large amounts of data. I view designing how much
data to send when, as just part of the robot design process. I use NXC for my projects and
have got many good BT ideas from Benedettelli' book, Creating Cool Mindstorms NXT Robots.
For NXT-G, there are some good ideas at <http://www.nxtprograms.com/>. See the
project Steering Remote Control for a project using BT.