Useful NXT-G Motor Block: Absolute position control

HiTechnic has released a new motor block that you can use in NXT-G. Here's an excerpt from the description found on the HiTechnic website.

Why the HiTechnic Motor PID Block?
This block is an alternative to the standard LEGO Motor Block. Unlike the Motor block, which when used with a duration of degrees or rotations, gives you relative control over the position of the motor, the PID Block is designed to give you absolute position control. With the standard Motor block, you might use it to go forward 45 degrees, go another 45 degrees, then go backward 90 degrees. Each time the motor turns an amount that is relative to the position that the block starts in. With the PID Block you specify an absolute position. For example, if you want the motor to go to position 45, you can pass in that value to the Set Point input of the PID Block and it will drive the motor to that position. If the motor starts at position 100, then it will go backward to 45; if it starts at 0 then it will go forward.

This type of control makes sense when your motor has a limited range of motion. For example, if you are using the motor to control the position of a robotic arm, you will likely want to make the arm go to a certain position and then have it do something. Since you may not want to keep track of the current position, it is often easier if you can just specify the position to go to. That is what this block lets you do. If you use the standard Motor block, then the direction and duration needed to get to a certain position will depend on the current position.

Here are some possible uses for the Motor PID Block:

- Steering mechanism on a car
- Linkage control system to follow the input from a sensor
- A selector mechanism for a sorter.
- A gripper mechanism that has multiple positions that you want to select between. Perhaps: Open, Closed, Crunch.
- A panning control mechanism where you want to accurately control the direction something is pointing.

Gus Jansson from HiTechnic demonstrates the block in the video below. Find more information and a download link here.

New block in the house : RS485 on NXT-G

Reproduced with permission from Xander's blog I'd Rather Be Building Robots

Give it up for my main man Andy Milluzzi who, with some help from John Hansen, created the world’s first NXT-G block that leverages the NXT’s RS485 communication abilities! Well done.
What does that mean?  Well now you can connect two bricks, back-to-back with a cable connected between their S4 ports and communicate at a blinding 921600 bps!  That’s quite a bit faster than regular Bluetooth and without the overhead of those mailboxes.
This opens up a whole new world of possible sensors! One of them being the new Dexter Industries NXTBees. How cool is that?
You can download the block from here: [LINK]. You will need at least version 1.05 of the LEGO NXT firmware to use this.

see original post here 

PS: looks like this could be quite useful for my W.5 project...

"My Blocks" Tutorial Available

The standard NXT-G programming system for the NXT includes a feature called "My Blocks" that lets you create your own custom programming blocks. This is especially useful when developing complex programs, so that you can build up more complex actions from simpler actions that you can re-use. Although creating a simple My Block is not hard, it gets trickier to make more complex and more useful ones, and there are a number of practical concerns.

For anyone wanting to learn more about My Blocks, I have posted this web tutorial, which starts at the basics and works up to more complex uses, including input and output parameters, simulating local variables, and various practical concerns such as testing and maintenance.

Multi-Bot for NXT 2.0

The Multi-Bot project for NXT 2.0 from nxtprograms.com is a robot vehicle that can take a number of different forms, including taking on several different modular attachments that can be used individually or combined in various ways, all using a single NXT 2.0 (8547) kit, or equivalent/replacement parts from other NXT/Technic kits.

Multi-Bot was designed to be a flexible "teaching robot" of sorts for NXT 2.0, especially as an aid to learning NXT-G programming, as you can use it to do a lot of classic robot vehicle tasks and expand it to do your own tasks. Home users of NXT 2.0 might find it a good way to learn about the basics of robotic vehicles, and especially in conjunction with the CD (see below) as a good way to learn a lot of NXT-G programming. FLL teams that have the 2.0 retail kit (8547) or equivalent parts and software might also be interested in using it as an educational tool before the regular FLL season starts or at the beginning of the season.

Building instructions for Multi-Bot, its variations, and several different attachments using all the standard NXT 2.0 sensor types are available on the web site. In addition, over 70 ready-to-run and fully commented NXT-G programs for Multi-Bot are available on the CD LEGO MINDSTORMS NXT 2.0 by Example. The programs range in complexity from beginner to advanced and cover different ways to control the motors, use the sensors, and more. The program descriptions are also included on the web site. Users or teams with some programming experience may want to see if they can develop similar programs on their own given the descriptions. Or if you like learning by example, get the CD and study the programs in each section (which are arranged in increasing difficulty) to learn NXT-G programming with ready-to-run examples all using Multi-Bot. Since you can quickly reconfigure Multi-Bot for the different tasks, you can cover a lot of programming topics without a lot of rebuilding.

Here is a video showing the included attachments for Multi-Bot and video clips showing tasks from selected programs on the CD:

AnyWay -- Build a Segway in 30 minutes

Last Saturday, I blogged about a Segway programmed in NXT-G. Many NXT Segways out there work very well, but they're hard to get to work with common tools software. Therefore, I decided to create a step-by-step tutorial to making your own Segway with simple tools. All you need is Any version of the NXT set (Hence AnyWay), plus the HiTechnic Gyro Sensor. The tutorial can be found here, and a video of the robot is shown below.

Windows 7 and the NXT?

I've recently gotten a scattering of reports of problems under Windows 7... but as a Mac user, I've got no way of testing it, and I'm not sure if these are problems due to working with a new OS, or just the smattering of problems that often crop up. So I'm curious and thought I'd ask the readership what they have heard or seen. Has anyone done a clean install of NXT-G (either 1.0 or 2.0), and what have been your experiences? Do they play together nicely, or have you found any incompatibilities between them?

Outside the Box - NXT-G on Small Screens

People love running programs on systems they weren't quite designed for, and NXT-G is no exception. Several people have found that it will run on very small laptops, but the screen size forces the configuration pane to be invisible, displayed off-screen. Problem.

TeamHassenplug has a solution.

Steve Hassenplug had this problem recently, and with some help wrote a wonderful LabVIEW tool that allows you to display the Configuration pane in a floating window - find it on the above page under "NXT-G add-ins". Now you can run NXT-G on screens with resolutions below N x 600, and have a nifty way to reposition information in the screen for taking screenshots, etc.

While you are there, you might want to check out some of the other tips, tools, and tidbits that pepper the site. There's a lot of information (and custom blocks) in the site.

And in the interest of full disclosure, yeah, some of the stuff on the site is mine as well :) .

--
Brian Davis

More NXT 2.0 pictures available

New images from toy fairs all over the world slowly pop up. Gadget review blog Pocket-Lint states, "Mindstorms NXT 2.0, will focus on offering 10 to 14-year-old boys a good robot experience rather than trying to appeal to the hardcore fans that use the kit.
Other new features include the inclusion of ten robot instructions from the software rather than two as in the previous model."

The article also tells us that this kit will cost around £200, which is about $285. However, these prices may vary per country: LEGO usually has different prices for different countries.

If follow the article link and click on more images, you will also see something which appears to be a new NXT- G feature, a remote control. This would suggest that the kit comes with newer software than version 1.1, which currently ships with NXT kits.

Update: One of readers correctly states that the target audience referenced on the Pocket-Lint blog doesn't cover the complete audience. Of course, Mindstorms NXT 2.0 is suitable and fun for both boys and girls, and I do not see the reason for a maximum age limit, either.

NXT-G 1.1 for $7.98US, Free Shipping

Available here.