Oct 31, 2006

NXT Palm control software

I received an email from Razix:

I wanted to inform you of a new software I have written for palm that allows you to remotely control NXT from a bluetooth enabled palm.


I have only tested it on Treo 650, maybe you can test and blog your thoughts on it. The reason I developed it was because there was no remote control software to control NXT from palm - only for Java cellphones andPocketPC as you have blogged at:http://thenxtstep.blogspot.com/2006/07/bt-and-pda-control-and-pcs.html

at least 2 user comments indicated they wanted a palm version.. so here it is!

Thank you, Razix! If you find this useful or have any feedback, please email and thank Razix for the software.


Hacking the RoboCenter

One of the folks over at nxtasy has reverse-engineered the Robo Center of the retail Mindstorms software. Want to add your own creations so other users can build them? Walk people through the steps to program your creations? Well, it looks like with the help of Guy Ziv's walk-through, we can add content to the official Robo Center sidebar. Take a look at it here, and thanks again to a lot of folks like Guy who are opening up tools to the community faster than the community can absorb them!

Brian Davis

Configure your system to develop with icommand, LEJOS

I received an email from Juan Antonio Breña Moral:

I have written a PDF to explain with comments and photos how to configure your system to develop with icommand, LEJOS.


I have created a new section of my site to show my advances in Lejos.


I would like to share this documents, because i have seen a lot of messages in differents forums about the configuration of Icommand, lejos.



Thank you, Juan Antonio.


UPDATE: Juan Antonio has updated the file... new version is here: http://www.juanantonio.info/p_research/robotics/p_lejos/docs/icommand0.5.pdf

NXT Car Update

Josh and Josiah, makers of the NXT Car, got a video of it in action. Check it out here.

Note: In order to see the video, you will need to have Quicktime Player downloaded.

Interesting NXT sculpture...

Found this on Brickshelf - thought it was pretty clever.

See the rest of the pictures here


James emailed me:

"A post on Thursday asked for drawings of the various NXT parts. I put some up over on my website, www.motocube.com. I only did some of the parts, but if someone requests it I can easily do the rest."

The offer is there, so please let James know if you have a special part you'd like to see used. Thanks, James.

Oct 30, 2006

FLL Scrimmage

I was invited to be a judge by the Forsyth Alliance, a group of schools in Forsyth County that encourages collaboration amongst teams from different schools. Yesterday I got to watch 16 individual rounds of the Nanotechnology challenges for this year's FLL competition and it was awesome. I saw some real ingenuity and some great improvisation during live play. I was also able to talk to the students for a few minutes about design ideas and show them one of my robots... they had a LOT of good questions and I could see the ideas forming in their heads as they saw a variety of robotic designs to try and modify...

Pictures from the event are here. If you are involved in any FLL practice tournaments and have pictures/videos you'd like to share, e-mail me the link and a small writeup and I'll be happy to share with the world.

I had fun... thanks to Forsyth Alliance for inviting me to participate.

Funny video

A nice warning for those of us who might tend to go a little far in our NXT experimentation. Thanks, William

Game of LIFE

Over at nxtasy.org, John has posted about a port of the old BASIC game of LIFE to the NXT. For those of us over a certain age, we all remember when graphics consisted of alphanumeric characters and text games (remember Infocom's ZORK? My favorite - Suspended).

Google Co-Op page

Our friend, Tony Buser, has created a nice Google Co-Op page that references many of the NXT sites out there, including The NXT Step... from his posting:

"I've been playing around with Google's new Co-Op system which basically allows you to create your own search engine that only searches a certain list of websites. (ala Rollyo) So I've put together an NXT search engine that indexes a lot of NXT blogs and a few api documentation sites. It has a home page here, but the url isn't very friendly. (hope they work on changing that) They have a system that lets you easily embed it into your own website, but it messes up the layout of my site."

Check it out and let Tony know what you think...

Oct 29, 2006

New stuff from HiTechnic

Be checking in on the HiTechnic website this weekend for an announcement. I can't say much more, but it does consist of multiple new products, one of which is going to blow you hardware hackers away.

UPDATE: The announcement is now up. Details below

NXT Color Sensor
NXT 3 axis Accelerometer / Tilt Sensor
NXT Prototype board
NXT Extended Connector Cable Set including extra long and short cables

Oct 28, 2006

Some great new stuff from Sivan...

Got this from Sivan:

The sensor ports on the NXT support a serial digital protocol called I2C, which was developed by Philips in the 1980's. I have built a prototype that shows how to interface to the NXT a simple I2C chip that provides 8 digital I/O ports.

Each one of these eight ports can be used as either input or output (and in some restricted ways also as both). These inputs and outputs are binary: they are either on or off. Input ports can be used for touch sensor (switches), for example. Output ports can drive LEDs, and through relays or other devices they can turn motors on or off. In my setup, two ports are used to drive LEDs, two other ports are used as inputs, connected to push switches, and four ports remain unused.

It turned out that connecting your NXT to this this interface chip is as easy as electronics experimentation goes, and programming your NXT to communicate with this chip is also easy.
Connecting your NXT to any home-made gizmo (like the one described here) can damage it. Beware.

Thanks, Sivan!

Slow news day...

Sorry for the lack of new content recently... a lot of us are working with local FLL projects and things are starting and taking some time from our schedules. I'm supposed to "judge" at a "practice competition" tomorrow and am looking forward to it.

I did meet with some 4th graders this previous Wednesday and had a lot of fun watching them demo their robots and ask questions. Some of the questions were VERY good and I was pleased to see that the students are asking questions about not only HOW things work, but WHY they work the way they do...

Good luck to all teams preparing for FLL... this Nano Challenge has some very tough components and I can't wait to see more robot solutions. Without giving away any details, if you are participating on an FLL team, feel free to email me and let me know how your team is doing and let us know if you're having fun.

Oct 26, 2006

Website that lists the angles and other dimensions of the NXT parts?

Hi all,

a reader brought up the question where to find information in the web about angles and dimensions of NXT parts.

Does anybody know about a site that lists these things?

Peeron doesn't, does it?


Oct 24, 2006

Compass Sensor use in FLL

A new question was just added to the Q&A section of FLL today about Compass Sensor use. The answer is a definite "no" for 2006/2007, but use in future competitions is undecided as of yet.

Oct 23, 2006

An Introduction...

Hi all,

My name is Rob Torok and I am pleased to have been invited to join the The NXT STEP as a contributor.

I'm certainly neither a LEGO nor a robotics guru, but I have been having fun with LEGO all my life. As a teacher, I have been using the RCX to teach robotics for some years now and am looking forward to seeing what my students are able to do with the NXT over the coming years...

As Jim pointed out a week or so ago, my MDP Profile was recently posted, so you can read a bit more about me and a couple of my robots there if you're interested.

Most recently I've been working on a couple of RobotC programs. I'll share these when I've had a chance to make them a bit more 'presentable'.


Bluetooth Serial Port To NXT in Linux

Tony's got a writeup here on how he's been tinkering with NXT and ruby-nxt. Be sure to leave him some feedback if this is beneficial to you. He's doing some interesting work and I've been looking into this Ruby language myself.

Oct 22, 2006

Reader submission

I received an email from Karl with some pictures and a link to a video... some really nice design work with a mixture of Technic and Brick pieces... and marbles. I'll let the video speak for itself.



Australian NXT Review

A review of the NXT from our Australian friends. Read ithere.

Oct 21, 2006

NXT Program and Memory Efficiency


The Lego Education Blog recently released a PDF file with lots of useful information on how to program more efficiently to save memory (take it from an FLL comptetitor, memory can become a problem). View it here.

On the sixth page, there's a section about mini blocks - special versions of move, motor, sound, and display blocks - that will be released from the FLL Website during Fall. These mini blocks will cut down on memory usage while retaining some of the functionality of regular blocks. From the statements about it, I think they'll be really useful in comptetitions for maximizing memory capacity.


Oct 19, 2006

Media alert - MUPpets on TV?

I've heard that there may be an interview with Steve Hassenplug, one of the original four MUPs, on "Daily Planet" tonight (19 Oct 2006) on the Discovery Channel Canada, at 7 & 11 PM. For those of you in Canada, please let us know about it.

Brian Davis

Building instructions for the Silberpfeil

Hi all,

back again from "No Internet Country", I've created building instructions for my March's NXT car, called Silberpfeil.
It has been a popular request, I might say, but as I foolishly didn't make an LDraw file of it then, I had to reassemble it first just from the two images and dwindling recollection.
Well, that displeasing experience (nothing such irksome as to have to reinvent something you know you have already mastered once upon a time in the past) confirmed my commitment never to disassemble a robot of mine again before having made a CAD file from it!

Some new faces

The NXT STEP community is growing... it will be easier for 10+ contributors to keep our readers informed than 1 or 2... and you'll get a good variety of opinions, news, and designs...


Friends' first NXT design

Recently, a couple friends of mine got a NXT, and they've really got going with it! The two of them, Josh and Josiah, built this awesome car. It's powered via two motorized wheels in the back, and steers the same way that real cars do. They even added the driver with his steering wheel! I especially like the way they installed the US sensor to look like headlights. They also used an ingenius way of doing rack-and-pinion-type steering without any gears:

A motor rotates the top white beam, which in turn steers the axles sticking out on the sides, to which wheels are attached.

View more pictures of it here

Anyway, this was a great first project, nice work guys!


New Contributor

Hi all,

I'm a new contributor here - some of you may recognize me as the guy who built the A27 Bionic Glove (posted earlier). I've had a little over 4 years experience building robots, and recently I got the NXT, and have been having lots of fun building with it.

Anyway, I'd like to thank Jim for inviting me, and I'll try to give you folks the latest and greatest information on NXT robotics. :-)


Question from Reader

A reader is looking for some help with a program. Apparently the Sound sensor is not breaking the LOOP block. See the picture here for the program.

Oct 18, 2006

NXT and Bluetooth Problems (Revisited)

As most everyone now knows, NXT Bluetooth connections can be fickle at best. (Much has been written about this on this blog).

Bram Fokke has his own cure for an ailing Bluetooth connection: scrap the propietary drivers and just use the ones provided by Microsoft on Windows XP. (You have to have Service Pack 2 to do this).

After a long-used Bluetooth connection of mine suddenly went south, I tried Bram's advice and it worked. His article is appropriately entitled, "Bluetooth Brawl". Read ithere.

Oct 17, 2006

NXT Awards, Holiday Sales, etc...

Here are some random links that demonstrate (I believe) the growing popularity of the NXT and its potential sales for the upcoming 2006 holiday season. I can't find any information on whether LEGO expects to sell out, but if you're considering buying one, I wouldn't wait until December.

Impact Labs - Top 12 Toy List

FamilyFun - Toy of the Year

Popular Mechanics Breakthrough Award

FAO Shwarz Toy Innovation Award 2006

HiTechnic Compass Sensor NXT-G block info

HiTechnic has posted a preview of its NXT-G block and configuration panel for its Compass Sensor. To read it, go here and click Products, then click More Information found in the NXT Compass Sensor section.

Oct 16, 2006

Google NXT

Jim has posted the blog statistics several times, and I found them interesting. So I thought I'd show the rest of you how your statistics are. I've been tracking the number of Google hits on "NXT LEGO" since before the official announcment, and the statistics are interesting. Some of the jumps appear to be artifacts of either how Google is keeping track or something else odd, but the overall trend is clear... and clearly impressive. Compare it to the number of hits for "RCX LEGO", for instance.

Brian Davis

New MDP profile

1 MDP profile has been recently (??) added.

Rob Torok

Oct 15, 2006

New Article by Sivan

Sivan has an article on how to use the Sound sensor as a clap counter... read it here.

Oct 14, 2006

NXT: Convergence of Design and Machine

In the "old days", computers and software could only simulate real-world designs. But today, computers and software can "target control algorithms directly to custom board designs", to quote Tom Shelley in Eureka Magazine.

In other words, computers can now put their designs DIRECTLY INTO the real-world product. According to Shelley, the NXT (with its LabView software) illustrates the melding of computer design with the machine itself. Read Shelley's articlehere.

Some great creativity

Over at NXTLOG there've been a LOT of creative submissions... I like this new one, the Trike. Very creative and true to the actual form of a trike... even includes the seat!

Learning BASIC

A while back, Peter sent me a link to a great article titled "Why Johnny Can't Code" - it's main focus was on how our younger generations might be losing out by not learning how to properly program using text-based languages such as BASIC, FORTRAN, Pascal, C, and others...

Well, I got an email from Cari recently and it includes a link for those of you who might be interested in a BASIC programming solution. It's not free, but the feedback and support for the product look good. You can check it out here.

I for one remember typing in my very first BASIC program on an Apple II - it bounced a ball randomly off the edges of the screen, similar to PONG but with no user control. Still, I was hooked and I have to admit that learning programming using line numbers (at first) helped me to figure out how to organize future programming projects...

I'd love to hear from some professional programmers out there... maybe some encouraging words to our younger readers who are interested in learning more programming...

Oct 13, 2006

A Roaming Program that "Sees" the Room

A simple but nifty NXT-G program that scans the room for the "open road", then heads in that direction. (Thanks to "ro1000" for posting this on Nxtlog).

Download ithere.

Cure for the Engineering Shortage: Mindstorms NXT

An editorial argues that schools can address the US engineering shortage by introducing engineering concepts to younger students (K-12). It lauds Mindstorms as a creative example of accomplishing this.

Read ithere.

Oct 11, 2006

More pics from school robotics club meeting

My wife took some more pics from today's club meeting.

NXTLOG Updates

Keep an eye on NXTLOG tomorrow for some updates... and if you haven't check it out yet, click here. Many have already started submitting, so if you've got something you're proud of, want to share, or just need to show off, create your account and get to work!

NXT: Available for the Holidays?

According to last week's Wall Street Journal, toys on Toy Wish Magazine's "Hot Dozen" list are often in scarce supply at Christmastime. (The NXT is on that "hot dozen" list).

Nevertheless, I'd be very surprised if the US faces a holiday shortage of NXTs, for three reasons:

1) Lego specialty stores in the US have been promised an adequate supply of NXTs, according to the Lego Store manager in my town.

2) A large number of "big-box" stores sell NXTs (Best Buy, Target, Toys R Us, Walmart), not to mention a slew of online retailers.

3) Stiff competition from the Nintendo Wii may increase the availability of NXTs. (The Wii will be in NXT's price range).

Still, NXT spot shortages DID occur in August of this year. (Some Amazon.com customers had to wait several weeks for their NXTs in August).

Is the NXT available where you shop in the US? How about Europe and elsewhere?

Oct 10, 2006

NXT receives award


Read the complete news release here.

NXT-G coding tips on-line

There's a nice PDF file up now on how to get the most, memory-wise, out of NXT-G. Take a look at it:

Writing Efficient NXT-G Programs

There's a lot of interesting tidbits here in just a handfull of pages, including how NXT-G shares some pieces of code... and how you can take advantage of that. The last point is perhaps the most interesting to me: "miniblocks", performance-oriented blocks that can be "added on". I like where this is heading...

Brian Davis

Wireless Cam Sensor not available

Maybe I did TOO good of a job on it, because I've been overwhelmed with email requests to purchase the wireless camera seen here.

The Wireless Camera you see here is homebrew. This means I made it myself. There is no KellyEngineeringGroup company (Kelly is my surname and this was meant as a joke). It is not an official LEGO product - it is not available for sale - you cannot buy it from HiTechnic or other vendor. I took a spare (extra) Light sensor and took it apart to obtain the shell needed for the camera. There was no wiring or soldering or any special skills needed other than the abilities to squeeze out superglue and drill a small hole for the antennae.

What I can provide you is a link to buy the camera and receiver here. Thank you ALL for your emails, and I'm sorry that I can't make one for you. But it's not hard. $30US (plus shipping fees) will get you your own camera... consider supergluing a small 3L beam to the bottom of the camera if you don't want to sacrifice a sensor.

I won't be able to respond to any more emails about the camera... sorry.

Oct 9, 2006

HiTechnic Compass sensor available

HiTechnic will start taking orders for the NXT compass online today. It will begin shipping on Tuesday, October 10. Cost is US$46.00 + shipping costs ($7.50 US and $18.95 International)

From the HiTechnic website, some guidelines/rules to remember:

The HiTechnic compass sensor will only operate correctly in a horizontal plane so you must keep the compass level for it to read correctly. This is very important so remember this when you build it into your robot.

NXT Firmware version 1.03 must be loaded in the NXT for the compass to operate correctly. You can check the firmware version by displaying the NXT Window in the Mindstorms software.

It is highly desirable to mount the compass at least 6 inches (15 cm) away from the motors and 4 inches (10cm) away from the NXT brick itself.

Try to make sure it is firmly mounted, if it bounces around, the readings may bounce around too.

Oct 8, 2006

NXT Wins 2007 Oppenheim "Best Toy" Award

Quite an achievement, considering this is only 2006. Read about ithere

Derrick's SketchBot information

Received some additional information from Derrick on the Sketching bot... (edited for length):

What I am attempting to do with this robot is to have it create dense pen drawings and use the light sensor to have the robot respond to the densities by choosing to switch to a different task in the program once the pen density reaches a desired point.

I had used previously to the NXT robot a RCX 2.0 kit to achieve a similar result with much success. When I designed the RCX I had used the ball point pen as the caster on the robot. The problem with this was that the pen always needed to be on the surface on the paper, so when the robot was doing an arbitrary task like backing up from the edge of the paper it was always marking.

I am using NXT as an opportunity to utilize the third motor as a means to pick up and put down the pen. This means that when the robot is executing an arbitrary task (i.e. moving back
to the center of the paper) it will not be marking on the page.

I have the light sensor on the front of the NXT to detect the black tape that I have
put around the edge of the paper so the NXT knows when it has gotten to the edge of the paper. The pen is secured to the extra motor in the center of the robot.

So far the most successful program I have created has 2 independent tasks running. The main task is the process of the robot drawing. What I have started to do to keep things from
getting to repetitive is by setting up a switch block in the task that has a couple of different "sketching" programs and the robot has a random block choosing between the two programs. The other program is waiting for the trigger of the black tape so the robot can back up
and turn around.

One of the initial problems I had was how to tell the NXT to pick up the pen when it found the black line, but not to pick it up if the pen already happened to be up. I ended up setting up a
logic variable for this. So when the NXT found the black tape at the edge of the paper it would check to see if the pen was already up or not. If it was then it would just back up and turn around. If it wasn't then it would pick up the pen before executing the back up and turn around command.

I am struggling with some of the quirks in the NXT-G programming like how to tell the NXT to immediately stop the present program when it finds the black line.

The drawings I have achieved so far with the RCX and the NXT project have obviously very non-representation and fairly geometric, but that is what I have really been going for.
Being an artist who primarily works with drawing media I find it to be a significant challenge to take the pen out of my hand and to make my interaction with the art making primarily about designing and programming the robot. I hope to eventually get program to a complexity where the NXT will have to make a lot of it's own decisions (albeit a bit randomly) on how it
will uniquely approach each drawing, but that is still a ways off!

Update on Juan's Esmeta Control Tower

Juan has posted some additional information on his new creation here. Plenty of videos and pictures, too.

BT phone control...

I got an email from Pedro - "After I saw there was not any applications to remote control the NXT from an ordinary java cellphone and many people were asking for it (there was only PC and PDA versions) I wrote one using an IDE called mobile processing. The app is still a beta version and only controls a bot but if I see that people are enjoying it I will put more work into it and implement a lot more functions :)"

Feel free to check it out here and give Pedro some feedback via comments. Thanks, Pedro, for submitting.

(You can also see the Pedro has developed some other NXT-related items...)


Oct 7, 2006

MIT Leg Laboratory: legged robots

This seems to be an older site of the famous MIT and some of you may know it already, but I've run about it just recently.
It shows an impressive collection of robots with different numbers of legs and a heap of most entertaining movies.
I love the kangaroo-like one!


Oct 6, 2006

Light sensor to Laser Pointer Hack

Kevin has submitted a step-by-step guide to converting an NXT Light sensor to a Laser Pointer... check it out here.

Oct 5, 2006

New BT article from Sivan

For those of you who have been enjoying reading Sivan's articles, he's just released a new article on Bluetooth - a very well-written article, I need to add.

Check it out here.

NXT on Lists of Top Holiday Toys

As Jim Kelly predicted, the NXT looks to be a hot holiday item. The trade publication Toy Wishes Magazine, after a review of thousands of holiday toys, has the NXT on its "Hot Dozen" list for Christmas 2006. Read about ithere.

Toys R Us also has the NXT on its list of top twenty toys for the holidays. (Let's hope that every customer who wants one can actually buy one). Read about ithere.

NXT tank, Mk II

Joe Meno has done some rebuilding on his NXT tank, moving more towards studlessness (and sporting a nice set of mudflaps over the treads as well). Both still pictures and a brief video (the dog is clearly not impressed):

Brickshelf gallery of NXT tank

YouTube video of NXT tank

Brian Davis

Open LEGO Mindstorms position...

I got an email from Soren with the following link... good luck to any of you who apply.


Hello NXT-Step World!

Greetings from Forest Edge Elementary School in Reston VA.

I finally had a change to take a club picture. Woops! I forget to include the NXT Kits. Oh well.
We are also missing about 12 students in this pic.

The club is comprised of five registered FLL teams which meet separately on the weekends at their coaches homes. I coach the young ones ( 8 and 9 year olds ) and also run the club at the school.
You should see the line up at this table!


Oct 4, 2006


Bram Fokke has updated his website and software tool - changed from visual Lego to NXT# (NXT-Sharp!)

Version .2 is now available. He's also including some sample projects. Let Bram know you enjoy his work and give him some feedback.

The new site is http://nxtsharp.fokke.net/

Gears and Pulleys Construction tips

During some random searching, I came across these little animated tutorials. I think they've been around for a while, but they may be new to some of you (as they were to me).

Some nice explanations as well...

An NXT Sketching Robot

If anyone has any more details on this NXT bot, let me know. The sketching appears to be random, but I could be wrong.

The other image can be found here.

LEGO Ed call for Robot Designs

Over at the LEGO Education blog, they've posted the news about the 4 NXT retail version bots (Spike, T-56, AlphaRex, and TriBot) building instructions being made available to the public... and they've also posted a request for designers to send in their own designs for possible inclusion.

From the post: "We’d love to add more models to the page, however. If you’ve got a model you think others would be interested in, we’d love to hear about it. Photos or drawings showing step-by-step building instructions make it even better, but feel free to share even if you don’t have those things. Send any models or links to NXT@LEGOeducation.com, or leave a link in the comments."

If you've got some new building instructions that no one has yet seen, consider submitting them to the LEGO Ed blog for them to share...

Reader robot submission

Juan Antonio Breña Moral emailed details about a robot he designed - the ESMETA Control Tower 1.0 - check out some images here. Not sure what it does, but I'll email him to ask.

NXT motors as clock hands...

Dick Swan has posted a couple of videos showing NXT motors used as minute hands for a clock. One video is using NXT-G and the other is using RobotC. Check them out here and here.

I may be wrong, but I think the "overshoot and correction" shown for the NXT-G version can be fixed with some creative programming... anyone up for that challenge?

New Yorker Mag Robot Cartoon wiinner selected

Click here for the winner

Interestesting that it starts off with "Jenkins"

That's the same name as my entry ( I admit that mine was not nearly as funny)

Still.. I wonder if The NXT Step blog can take partial credit for this win.


Oct 3, 2006

LEGO Retail Directions On-line

Several folks with the educational version have asked for the instructions for Spike, Alpha Rex, etc., since these do not come in that set. Well, LEGO Education has posted them! Take a look over here:


Thanks to James Isom who worked (hard!) to format these, and to LEGO Education for releasing them!

Brian Davis

NXTLOG submissions

When the NXTLOG feature begins, you will have the opportunity to share your creations with the rest of the world. You'll have the ability to add pictures, building steps, notes, and video and visitors will be able to comment on your designs.

I plan on uploading details of many of my designs, such as the one you see here.

You'll hopefully see all the different sensors in action, along with some custom sensors and third-party sensors (such as the HiTechnic Compass sensor). I'm looking forward to a LOT of ideas from participants on NXTLOG.

You've probably got questions about what you're seeing here... I hate to do this, but you're going to have to wait just a little longer to get more details. I promise to put EVERY DETAIL of this design on NXTLOG and that means you'll have access to it, too. (I got the idea for providing this teaser from the Jeep design over at nxtasy.org.)

And, if you've figured out what it is, your next question is probably "Does it work?"

Well, here's your answer. (Apologies for the blurry image - I moved.)

Reader Question Submission #4

Jean-Marc emailed: "Hi, I am just starting out programming the NXT robot. I want to use one as a master with levers which will control the movement of the slave. I will use the motor as a rotation sensor in the master, but I'm not powering on the motor (it's to attempt to duplicate Steve's "omni"). Here is my question: When I start out with the lever in the straight up position, what numeric reading will the rotation sensor give me? If I want to move the lever forward and backward in a range of approximately 180 degrees, what is the reading of the "up" or neutral position? Thanks for your help!"

Any thoughts or answers?

Sept 2006 Visitor stats

For Sept 2006, we had 23,746 visits to The NXT STEP, with 9,926 of these being unique visitors. Thank your for your participation and support - keep submitting those questions and we'll try and find you some answers as well as make them available for discussion and comments.

Oct 2, 2006

Some new NXT videos and Building Instructions

NXT Tank

Moving Crates

Over on Flickr.com, someone has posted the steps for a new bot - find step 1 here.

Reader Question Submission #3

Kurt emailed: "We haven't spent a lot of time working with light sensor calibration yet. Once you calibrate the light sensor, how long does it stay calibrated? For the duration of the program, until the NXT is turned off, until you recalibrate it? To put it another way, if we use multiple programs to accomplish the missions in an FLL competition, can we just calibrate the light sensor before we begin the first program, or do we have to calibrate it at the beginning of each program?"

Great question... anyone have a definitive answer?

Update to Visual Lego

Bram Fokke emailed to let us know that Visual Lego 0.2 is available for download. Some new features have been added such as support for the Ultrasonic sensor.

Check it out here.

Report from the first European NXT event

Michael Brandl (MDP & MCP) took part in the first European NXT event in Zurich: see his report (on German, though, but there are a lot of images also).

Reader Question Submission #2

We received this question: "If I want my tribot to turn 90 degrees, how come I have to code the motors to spin in opposite directions each for 180 (or a bit more) degrees? I mean, why 180 degrees if I am turning the robot 90 degrees?"

Click on the image at left. If you take the NXT stock wheels (2.25 inches in diameter) and calculate their circumference, you get approx. 7 inches. Now, assume those wheels are mounted on a bot as shown, with a distance of 5 inches between them and you want the bot to spin a quarter-turn in place (left wheel spins one direction, right wheel spins the opposite direction).

When the Bot makes a quarter turn, each wheel has traveled 3.925 inches (along the path indicated by the red circle). If 7 inches = 360 degrees, then a simple calculation shows that 3.925 inches is approx 201 degrees - not 90.

The bot as a whole has made a 90 degree turn, but the wheels have turned substantially more.

Did this help? Can someone verify my math and that I've done this correctly?


BlueTooth: playing with blocks

So you’ve gotten two NXTs connected via BT, and sent a couple of files across for no apparent reason (although I’ll bet such filesharing becomes a fun pastime at FLL events this year; everybody bring your favorite sound file to share ;-). How do you use this within NXT-G? Once connected, NXTs can send BT messages to each other using the Send Message and Receive Message blocks. And unlike IR messages with the RCX, limited to a single number, these can numbers, Boolean values, even text strings (yes, you can turn your NXT into a really bulky instant messaging system ;-).

The tricky part is those connections – remember how the master and slave NXTs showed that they labeled the connection with different numbers? Those are the “addresses” of the NXTs. But each address can have multiple mailboxes as well, making for yet another way of sorting out all the BT mail that ends up flying around. It’s similar to how mail gets to an apartment building: all of it gets sent to the same building (which NXT, identified by a connection number), but you can also tag each message as headed for a particular apartment (the mailbox number).

If you take a close look at the Send Message block, you’ll see you can tell it where you’d like the message to go: what connection to send it out on, and what mailbox in the receiving NXT to pop it into. But where is that information on the Receive Message block? Here there is no connection to select, so how do I tell the Receive Message block where to get messages from? The answer is you don’t: all messages sent to a single NXT are accessed through the Receive Message block, just like all your mail is sent to your address (even if some of it started in Austin, TX, while another was sent from Billund in Denmark). In short, NXT-G BT messages have no return address built into them (although there are ways around this… those mailboxes again).

Confused yet? Here’s a simple set of programs for the two connected NXTs. One (“DiceMaster”), running on the “master” NXT just generates a random number to send to the other one, and then waits for a return message from the second NXT telling it if the sum of all the numbers has exceeded some preset limit. The other program (“DiceSlave”) listens for a number to be sent to it, and then adds it to the total and checks to see if the limit has been exceeded, sending a message back to the master to let it know the result. Simple, but it does show how messages are sent both from the master to the slave, as well as from the slave back to the master. Note that a slave NXT can only send a message back to the master, so for a slave there is really only one outgoing connection: connection #0. And of course all the messages coming into the slave come only from the master as well, which is listed in the slave’s Connection menu as on connection #0. So I tend to think of this in the terms I used in the program comments: slaves both send and receive all messages over connection #0, while from the master’s point of view, it can send messages out to any one of three addresses (#1, #2, or #3), but again receives all incoming messages along a single “line”, which I still think of as a “connection #0”.

Now, for any of you with two or more NXTs, experiment! And let us know what new quirks or features you uncover.

Brian Davis

Oct 1, 2006

The NXT STEP goes German (also)

Now that the NXT is available in Germany also, it's time for The NXT STEP to be available in a German version too, isn't it?
This squares with the breaking of the 500 posts border and seems to me the next logical step on our way to world domination. ;-)

Hence, a German sister site has come into being, called Die NXTe Ebene (which means more or less the same as The NXT STEP).

For a start, it will provide translations of the posts to-be in The NXT STEP (or of abstracts of the longer posts (as long as Brian is out of all reason not willing to learn German)).

With the site, we hope to achieve in particular young German NXT aficionados that might not feel completely at ease with the english language yet.

Bis dann,
Matthias Paul (editor of Die NXTe Ebene)

Post #500

This is Post #500. Unbelievable.

Thanks to ALL of our readers for their attention, assistance, questions, comments, critiques, and overall participation.

Reader Question Submission

Received the following question: Please feel free to add your comments to my own.


What are the recommended (or even required) add-ons for the NXT set? I just bought the set, but also felt the need to buy a couple of Technic sets so that I can big builder bots/etc.

Jim's Answer: As of right now, there are no "REQUIRED" add-ons... there aren't even any NXT expansion sets yet. The NXT is still considered quite new. There are a variety of 3rd party sensors now available from Mindsensors.com and HiTechnic has partnered with LEGO to sell their sensors (see an earlier post on the Compass sensor I tested). I'll let readers make suggestions for other sets that you might like...

BlueTooth: making connections

To me one of the most exciting aspects of the new NXT is BlueTooth. The ability to have a secure means of communication, and out of line-of-sight was something that was sorely lacking in the RCX. The first step is getting two (or more!) NXTs talking to each other. To be honest, this is in the user’s manual, p34-37, but a brief run-through might be useful.

Take two NXT bricks, and turn both of them on. Now use the BT menus to make sure both have BT turned on, and make sure both are “visible”. If you’ve never paired these NXT bricks with any other BT device, you will find the “Contacts” menu item seem to do nothing – there are no previous contacts recorded, so this menu is essentially blank (if you previously paired your NXT brick with a BT-capable computer, you’ll find at least one entry under “Contacts”, that of the computer itself).

On one of the NXT bricks, under the BT menu select the “Search” option. The NXT will search the local area for any recognizable BT devices, which may take a few seconds (note: if you do this at, say, NI Week, a major technical trade conference, where literally hundreds of folks are walking around with BT-equipped cell phones, laptops, and other devices… well, let’s just say I gave up waiting after awhile). After a while, the NXT pops up a list of the BT devices it has found. Select the other NXT brick from the list, and then connect on “[1]” (connection #1; you could use any connection, but for now I’ll stick with the default). The first time you do this, a “passkey” dialog will pop up on both NXTs; both of them have to accept the offered passkey (usually “1234” unless you really want to change it). Once you’ve done all this, you’ll see that the little “half-diamond” symbol in the status bar of the NXT bricks has changed to a “full diamond”, showing a BT connection. That’s it, the two NXTs are now linked via BT. If you want to follow the directions on pg37 of the user’s guide, you can now send files (but strangely not image files; I’ve no idea why that got left out) between the two NXTs.

By the way, the next time you want to connect these two NXTs, you don’t need to go through the whole searching and passkey circus. The NXT brick has obligingly recorded the name and status of the new BT device, so all you have to do to establish a connection next time is go right to the “Contacts” submenu, and select what NXT you’d like to connect to (and what connection to use). Handy.

Why did I bother walking through this, when it’s already in the user’s guide? Besides the fact that some people (none of the readers here, I’m sure) don’t actually read the entire user’s guide, I wanted to point out some quirks that become very important later. With the two NXTs connected via BT, take a look at the “Connections” menus on both of them. The one that you started the connection from (called the “master”) lists the other as on “[1]”, while the second NXT (call it the “slave”) lists the connection to the first as over connection #0 (“[0]”). Remember that – even though these two NXTs are connected to each other, they “see” the paired device on a different “connections”. Furthermore that initial NXT that you initiated the connection from has special standing; from it you can initiate other BT connection to other devices (like still more NXTs).

Brian Davis

NXT available in Germany

Today, I ran over some NXT kits in my local LEGO store in Freiburg, Germany (for a price of 269 EURO).
Maybe some of you have seen them in some stores in Middle Europe already, but for me those were the first ones I've ever seen commercially available in Germany.

Geht hin und holt ihn Euch! ;-)

Bluetooth confusion...

I got an email from William C. who asks "Is there such a thing as a hand-held bluetooth remote control (like theinfra-red one for the RCX) that I can use with the NXT? My cell phone isn't bluetooth enabled, and I don't want to have to buy another NXT just to get the benefits of remote control."

Bluetooth confuses me, too, William. Mainly because I've never been able to get it working on my PDA (incompatible Bluetooth version). I've got a new laptop coming in a few weeks that has built-in bluetooth so I'm hoping to learn some more there.

I've got 2 NXT Bricks and have had some limited playtime with using them together, but again, I'm not an expert. If you've got some comments for William (or me) regarding bluetooth options, please share your comments with us.
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