Feb 28, 2009

Ogre; a color-coordinated NXT "tank"

Most of the times my creations are poorly color-coordinated; I just use whatever parts I need functionally and don't worry about how it looks. But with the black NXT (in other words, with an option), I started thinking more about how to utilize the color. While I like the white/gray color scheme, the darker pallet had me thinking more along the lines of a zamor shooter... and I already had the mechanism, and enough dark studless parts...

Thus was born Ogre:

The four zamor launchers can fire a little over 9 balls each second, with a large "tray" on the top that feeds about 50 of them and allows for easy reloading. The tank treads have the upper point of the triangle "sprung"... the tension on the tread is maintained by a LEGO shock, so that the treads do not have any slack in them (and when going over a bump, the treads can "stretch" slightly to compensate). It doesn't use any NXT motors (after all, they didn't go with the color scheme), instead driving the treads and the launcher using the PF XL motors. This gives it a nice easy way to run it as well: with the NXT off, Ogre can be remote controlled using two stock PF remotes. But turn on the black NXT, and it can control the entire vehicle using the Hitechnic IRLink, in a fully autonomous mode where it can "hunt" for isolated targets, center on them, and then launch a volley of spheres while advancing towards the target (and disengaging when the target is no longer present). Another fun aspect is a small spy cam mounted to one side. With that, both remote control an dautonomous modes are a lot more fun as you "ride along" on Ogre as it roams across the countryside. Or, well, the living room.

Originally I wasn't sure of the black NXT. And for functionality, after all, a regular NXT does have the same feature set. But after playing around with it, it has given me some ideas for different color schemes, something that has always been rather lacking before: after all, the RCX had just one color (one I liked, but still... only one).

Brian Davis

Feb 27, 2009

Black NXT!!!!: What’s NXT?

Today LEGO is launching the long awaited Black NXT brick! The limited edition black brick is being launched as part of the MINDSTORMS 10 year anniversary.

Only 1998 of the limited edition have been manufactured and being sold. [The magic number, 1998 also happens to be the year the original MINDSTORMS was launched].

LEGO has said that they have seen a popular demand for the Black NXT, so they made an exclusive run of them.

If you want to purchase a Black NXT before they run out, you will be able to order them from amazon.com  for $169. I think there is a free shipping option for US customers.

It will also be sold through the LEGO shop@Home for customer living in Canada and USA.

It is a shame they did not make matching black motors and sensors to go with it – but still – you can make some really cool robots using the black NXT and some black TECHIC pieces. 

In the coming weeks we will be sharing some really cool black models that incorporates the black NXT.


Have a great black Friday!

New Zealand

Feb 24, 2009

Queen on NXT - Imaging on NXT - Part 1

If you grow up in the UK or one of the commonwealth countries (e.g. Australia, New Zealand, Canada ...), you would have grown up seeing a portrait of Her Majesty the Queen everyday - whether it is on a postage stamp or on every single piece of money you have in your wallet!

So I thouhgt I will scan a portrait of the Queen from the Australian five dollar note and put it in to my NXT.

And here is the result:
I will post Part 2  in a 'while' which will walk you through how this can be done in less than five minutes.

In the mean time anyone want to guess how it was done?

The only clue I can give is that it was NOT done using nxtRICedit by Andreas Dreier's - which by the way is really cool application.


Feb 22, 2009

Wichita State University's 2009 Mindstorms Challenge

Students from the Wichita, Kansas area converged on WSU for the 2009 Mindstorms Challenge which took place today, February 21st. The event is sponsored by WSU's Colleges of Engineering and Education. Students from three levels (beginner, intermediate, advanced) competed for trophies in their respective divisions.

In addition to the formal competition, there was a large "NXT Zoo" display from students in the area. Several of the animals were directly or indirectly based on animals from the NXT Zoo Book.

What follows are pictures from today's event:

The following are pictures from the "NXT Zoo" exhibit, including some photos of Fay Rhodes with students and their robots:

Congratulations to WSU on a varied and well-run event.

Do you know of other "off-season" Mindstorms events or workshops in your area? Let us know about them here.

Feb 21, 2009

New sensors from MindSensors.com

The development lab webpage from Mindsensors.com tells us that they are working on three new sensors for the NXT. You can read about two more in a previous post.

Line Sensor for NXT (NXTLineLeader)
"This is actually an array of sensors with controlled light source, to detect a line. The sensor will be easy to mount on your NXT robot, facing ground, looking for a line. The possibilities of an agile, fast robot, precisely maneuvering the arena are limitless."

PF Motor controller for NXT (PFMate)
"PFMate is designed to be a closely integrated controller for PF motors.
This device will attach to your PF IR receiver, and controls PF motors with high reliability. It is designed to attach to one receiver, however you can control upto 4 receivers, by mounting it at a distance.
Using this controller you will be able to control speed, direction and braking/floating actions of PF motors."

"This is an encased version of the popular NXTServo.
Just like NXTServo, this can control 8 RC Servo motors and has on-board programming capability (freeing up your main NXT processor from repetitive motion control tasks)."

The PFMate is close to the final stage and should be released fairly soon. I'll make another blog post on that one soon as well.

NXT-G 2.0 Datalogging

I've had the chance to have a good play around with the new education version of the software, in particular the datalogging aspect.

Whilst it's possible to do datalogging in previous versions (check out some of Brian's amazing posts) the new version ties it all together in a nice GUI that I think will appeal to many teachers.

Each experiment has it's own Configuration panel where you can specify the sampling rate, overall experiment length and the sensors you'll be using.

Once setup, you can run the experiment in either Real-time or remote mode. Real-time allows you to see the data as it's captured whereas remote allows you to download the experiment, take the NXT to another location and upload the data once the experiment is finished.

NXT-G2.0 produces some nice graphs and enables you to to do some basic analysis. This is the graph that was produced when I logged the light levels in a room for 24 hours.

Overall I really like it. It is quick to setup and run experiments and the data visualisation is quite nice. If you want to do more analysis you can export the data to a .csv file and open in Excel.

Here are a few more graphs I made.

NXT bouncing on a rubber band, with the Ultrasonic Sensor measuring the distance to the ground.

Temperature in a room over 24 hours

A cup of boiling water cooling normally(white) and after dropping in an icecube(orange)

A ball bouncing next to the Sound sensor

Damien Kee

Feb 20, 2009

NXT Transmission

Although I've been really busy with FTC ever since the competition got underway, I've still found some time here and there to work on NXT projects. One concept I've always been interested in is the idea of making a certain number of motors able to drive a larger number of mechanisms, one at a time. So I put together a simple transmission design, in which two motors can drive each of four axles, one at a time. The first motor turns a gear which can drive gears on each of four axles. The second motor drives a rack-and-pinion system to move the first motor to across the four axles. The user can press the left and right arrow keys to switch from driving one axle to the next.

Here you can see the four axles with black gears on them, and the grey gear on the motor which drives them.

Here you can see the rack-and-pinion mechanism for moving the first motor across the four axles.

You can see a video of the robot in action below:


Although it would probably make a robot more complicated, something like this could be useful in FLL, where you're limited to three motors, since it could enable you to have more mechanisms on the robot at the same time.


Feb 19, 2009

Review: NXT Temperature Sensor

I realized I have a lot of sensors. I should really review them :).

I've been using the new NXT temperature sensor (mentioned here in the blog a while back) for a couple of projects, and decided to blog my opinion of it. Note this isn't even remotely authorized, approved, or perhaps even noticed by LEGO et. al... these are just my experience and opinions, your mileage may vary.

Both the old analog temperature sensor (product ID W979889, $38.95, although you need a conversion cable to use it with the NXT) and the newer digital temperature sensor (product ID W979749, $39.95) are available from LEGO Education (they're not normally distributed through the retail arm of LEGO). I've been using these for a number of projects, including monitoring the temperature in my house and freezer, and recently for instrumenting a model geyser (in my kitchen... yeah, it's messy around here).

The old sensor is analog - it actually put out a voltage that changed with the temperature that the NXT or RCX had to digitize, resulting in only 1024 possible temperature values. This worked fine, but it has a number of limitations: -20 to +50 °C (so it won't work in boiling water), poor accuracy at the extremes, and limited resolution (0.2° C, but the actual accuracy is somewhat less than that). Physically the sensor also has a fairly "short" safe temperature probe: 2.4 cm long, but only the last 8 mm are "sealed" in metal, so it can't extend very far into liquids. On top of this, to use it with the NXT requires the conversion cable, another (separately order) part.

The new sensor is digital: it converts the measured temperature to a number with far more precision (up to 12 bits), potentially resulting in a temperature resolution of 0.0625° C... and in addition, the with the sensor itself doing the measurement it is much more accurate across the entire range of measured temperatures. Furthermore, the new sensor has a much higher range: -40 to 125 °C (although LEGO recommends only -20 to 110 °C), not only a drastic expansion, but one that now includes the boiling point of water. And to use this new high-temperature range, physically the sensor is improved as well, with 6.4 cm of sealed metallic probe to protect the probe from liquids (more than twice as long as the older version). Both versions come with the cable integrally attached to the sensor (probably to avoid problems with using electrical connections around liquids), but the new version sports a much longer 50.5 cm cable.

Actually testing the sensors points out some other very important improvements. I put both sensors on a common mount, and dipped them into icewater, followed a short time later by dipping them in a cup of hot tap water. The results were dramatic: despite appearing larger (and therefore, perhaps, taking a longer time to reach equilibrium), the new temperature sensor responded much faster (about 5 or 6 times faster) to changes in temperature than the old version. Dipping the probe deeper into the cup of hot water (something you can't even do with the yellow one) showed another interesting fact: the actual electronic sensor seems to be at or very near the tip of the probe, allowing you to memeasure, for instance, how the temperature changes with depth in the cup of water, or at very specific points on a surface. A detailed look at the reported temperatures also shows the much smoother profile generated by the higher-resolution sensor, compared to the more course measurements of the previous version. Dipping the sensors into near boiling water showed the improvements even more clearly... and showed the younger sibling clearly outperforming the older time-tested version in a bath of near-boiling water.

For science teachers and others who use the NXT to record environmental variables, there's no question in my mind: the new sensor is far superior to the old one. this doesn't mean the old one is worthless (far from it), but when choosing between the two in a new purchase it's hard to find any reason to select the analog version. If pressed, I'd say the only downside of the new version is the fixed cable length - with the RCX sensors, you could always add another cable end-to-end to extend it, while this is very difficult with the NXT sensors (and really, may not work well over a meter in length anyway due to I2C issues). As I mentioned above, I've been studying how a geyser operates by building a small model (a meter or two tall) in my kitchen (note: I'm probably safe in saying working with explosive, boiling liquids is NOT what LEGO recommends doing with the NXT). I placed the sensor tip in the geyser outlet, where it was exposed to splashing, boiling water and live steam off and on for more than 12 hours of run time, protected only by a plastic sandwich bag over the sensor body. It handled this sort of abuse just fine, and revealed the striking regularity of the model eruptions, as well as allowing an estimate of how much hot water was discharged. This would not have been possible with the old sensor, due to both the sensor housing and the limited temperature range.


Analog (old) Temperature Sensor:
  • Analog reading (10 bit digitization onboard the RCX/NXT)
  • Range: -20 to 50 °C
  • Resolution: 0.2° C
  • Probe length: 2.4 cm (0.8 cm metal)
  • Cable length: 15.5 cm
  • Note: poorer accuracy and resolution near sensor limits.
Digital (new) Temperature Sensor:
  • On-sensor digital conversion (up to 12 bit resolution, communication via I2C)
  • Range: -40 to 125 °C (can handle boiling water)
  • Resolution: 0.0625° C
  • Probe length: 6.4 cm (all metal)
  • Cable length: 5o.5 cm
  • Note: much faster thermal response than older version (low thermal mass)
OK, what can I do NeXT :) ?

Brian Davis

Feb 18, 2009

Comment changes - ID required

We've been getting slammed with spam in our comments so, for now, commenting will require a valid Blogger account name and Anonymous postings will not be allowed. We may turn this off down the road, but for now, it's the only way to slow down this junk. Apologies to our readers for the extra step required to comment.

NXT Magnetic Grabber

From the description:

"Eelco Klaver used a magnetic latching solenoid to build a magnetic grabber. The solenoid used is designed for low duty cycle applications where the solenoids energized position is needed for an extended period of time. The plunger latches magnetically in his basic position, until a negative electrical pulse is applied to allow the plunger to unlatch. Elco also build a mechanical guiding system to allow the plunger to reliable enter the hole of the solenoid."

Detailed information is here, at the bottom of the page via a PDF link.

Feb 17, 2009

AlphaRex's RoadTrip to Taj Mahal and Mumbai in India

AlphaRex saw one of the wonders of the world, in Agra, India.

AlphaRex would love to play in one of India’s blockbusters.

Find out about his visit and view the picture album here.


NXT driving a flight simulator

Chris Anderson, Editor in Chief of WIRED magazine (and builder of the NXT/RC Plane) sent over this link of an NXT controlling a flight simulator. Click here for more information.

Feb 16, 2009

Interactive Speech Utility for the NXT?

This company claims to make an interactive speech utility for the NXT.

Has anyone used this? More info is here.

Feb 15, 2009

FTC NJ State Championship

Power Surge competed at the FTC NJ State Championship tournament on Saturday... another really fun event! 37 teams competed in the tournament. We won all our matches again, and recieved the Winning Alliance award with our alliance partners 121 Rhode Rage and 248 "P J FTC #2." We also recieved the Innovate award. The Inspire award was given to team "Techno Chix".

Congratulations to all the winners!


Feb 14, 2009

Updated Homebrew Sensor (Galvanic Skin Response)

Michael Gasperi has a long history of custom (and useful) hacked sensors for both the RCX and the NXT. He recently updated his page with an NXT version of a galvanic skin response sensor. Typically this gets labeled as a "lie detector", but it's actually a lot more useful then that (I mean, how often does somebody you think is lying let you wire them up to some custom device?). Take a look, and let us know if you build something with it... or what the results are:


Truthfully, I think the neatest use for this would be simple biofeedback. Imagine something as simple as the NXT "singing" a tone that corresponds to the sensors value, and then trying to control the sound by controlling your mental state. This looks like a sensor I really need to build.

Brian Davis

Feb 13, 2009

NXT Area and Volume Calculator

This NXT Area and Volume Calculator is a little math exercise for your NXT, which gets it to act like an electronic "rolling tape" measuring device, to calculate length, area, and volume in both metric and English units.

As some of you may know, the new NXT-G 2.0 software from LEGO Education has added support for "floating point" (non-integer decimal numbers such as 12.3) numbers and math. I was pondering what this meant for users of the existing NXT-G 1.x software, which only supports integer numbers and integer math. So I decided to cook up a little exercise to do some math that could benefit from floating point, but still done the integer way, so the program for this project will work in either NXT-G 1.X or 2.0.

For those interested, here is a brief summary of some of the issues. A basic technique of integer math is to pay attention to the order of operations and store results scaled up in precision if necessary. For example, if there are 2.54 cm per inch, how do you convert cm to in without decimals? Answer: in = (cm x 100) / 254. And if you wanted more precision, you could carry around tenths of cm (mm) and tenths of inches as integers, do your math that way, then divide down before displaying. A gotcha to look out for is "overflow" of your integers, which is not usually a problem with the NXT's 32-bit integers, but in this project it gets close to being a problem in practice. The measurements are stored in cm internally, and if you tried to calculate the volume of something as big as a house, you would overflow the integers. However, I set my sights on nothing larger than a room (and precision no more than cm), which works out, so I didn't have to do anything special. But FYI this points out something that floating point numbers do very well, which is handle a large variation in dynamic range (measuring very small things and very large things with the same program) without a lot of special handling in the program. If this program used floating point, it would be simpler, more accurate (could have used mm accuracy internally), and handle both larger and smaller objects at the same time. These issues can still be solved with only integers, but it gets very messy, especially in a block language like NXT-G. And speaking of messy, the last part of the program, which displays the volume in gallons displayed displayed as a decimal number rounded to tenths (e.g. "12.3") is a serious pain using integers and would be much worse still if you wanted to display more than just tenths. The new floating point number-to-text block in 2.0 does all this for you. No normal NXT-G 1.x user would want to deal with this, so a solution in practice for 1.x would be to use some external/imported blocks to do the messy parts, but you would still need to be aware of what unit/precision you are storing where, and whether that will suffice for your application. Or maybe just import a whole floating point support library if you need it (anybody have one of these?).

Feb 12, 2009

NXT 2.0 Expectations

I'd like to ask our readers for some commentary here - I'll ask that The NXT Step contributors hold back from the discussion. (Also, some of the contribs, myself included, are members of the current MCP group, so I'll go on record as saying our ability to participate in this discussion is limited for obvious reasons.)

So, here are some questions for discussion/thought/debate - keep it clean, polite, and on-topic, please.

1. The NXT 2.0 kit is coming - what are your thoughts on the kit? (See earlier post here and here for details that are publicly available.)

2. If you're an NXT 1.0 owner, do you plan on purchasing 2.0? If not, any particular reason?

3. Is there anything you're looking forward to with 2.0?

4. Any concerns or gripes with 2.0 (or with 1.0 that might or might not carry over to 2.0)?

Feb 10, 2009

New NXT Blog

Be sure to check out one of the newest NXT-related blogs over at http://www.mindstormsworld.blogspot.com/ - the contributors are off to a good start!

Feb 9, 2009

LEGO Flexpicker

Chris S. sent news of his 4-NXT-Brick version of a commercial/industrial robot called the ABB Flexpicker. Link to the video is here.

Feb 7, 2009

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

Feb 6, 2009

NXT 2.0 first look review

Gadget review blog Pocket Lint features a first look review of the NXT 2.0 set. Note that if you look at the video screen in the back, you can see the new Alpha Rex walking.

Feb 3, 2009

Climate Connections Perfect run 400 points

Technobotts³ Preparation for the UK Final

This year the Technobotts3 FLL team had a fairly successful regional heat, they walked away with two trophies: Robot design award and 2nd place overall. With 280 points they had qualified for the UK finals in Loughborough.
Encouraged by the unreliability of their old robot, the team voted for yet another total redesign. Although this may sound a bit risky, they had also done it two years ago before the finals, to great success.
So it came as no great surprise that the first ever practice run with our new robot achieved a score we were aiming for 400! And here's the video of us getting 400 in only 130 seconds.

Well done !!

(Origional post by NXTBoy)


NXTLog Video Challenge

Details here.

FTC Delaware Regional, Part 2

EDIT: You can see videos of our robot that Ken Johnson posted on the FTC blog, here.

Like I posted about earlier, the FTC Delaware Regional Tournament was held on Saturday. What an exciting event! It was held in conjunction with both the FLL and JFLL Delaware State Championship, so it was a pretty major event with lots of teams and spectators.

Speaking of FLL, I was realizing at the tournament that I've now seen FLL from three totally different perspectives: as a team competing in it, as a referee, and now as an outsider looking in. It was interesting to see how vastly different these perspectives are, and it's also something that's good to keep in mind when one is refereeing or competing.

2945 Power Surge had a lot of fun competing and watching other teams compete. Our robot performed way beyond our expectations; we won all 11 of our matches, and recieved the Winning Alliance Award (equivalent to FLL's 1st Place Robot Performance) with our alliance partners 3165 Twisted Bots 2 and 7 Techbrick, and the Inspire Award (equivalent to FLL's Champion's Award). Our highest score in a single match was 213, in which we scored all of our alliance's points; no other alliance got higher than 100 points, and we broke the highest known record, 166 points. The second place alliance was composed of 134 R.A.T.S., 404 Charter Impulse, and 395 RoboAuks... congratulations to them and all the winning teams!
Here's a few pictures of the event:

Some of the audience... there were many people there!

Working on the robot before the matches... we had to do a good bit of tweaking to make the robot work with the competition fields (which were somewhat different than our practice field).
The tournament supplied a nice LEGO "brickbox" (instead of a sandbox) for the little ones to play with when they got a little bored. :-)

#2945 Power Surge with our robot and trophies. From left to right: Kevin, Phyllis, Chase, myself, Isaac, Timothy, and Kathleen.

The tournament was a really fun experience for us, and we're looking forward to our next regional in NJ next Saturday.

As always, you can learn more about the team at our website: http://www.teampowersurge.org/.


Feb 2, 2009

Dutch FLL2009 FINAL (BeNeLux)

Saturday 31 January in Utrecht was the Dutch FLL Final, in total more then 250 teams competed and over 2500 visitors were present.
The polar bears from Hillegom won the first price, and are invited to go to Atlanta.

The below team (windkracht zeven also form Hillegom) won the second place and with that a ticket to the Open European Championship in Kopenhagen (DK) in May.

The team that won the third place (WereldWierdeWijs from Almelo) will have their project worked out in real.

Team watt build this impressive robot that could do all but 3 missions!

This robots was featuring a real interesting principle called MOT, (Main On Top).
They say that removing and attaching parts during the game costs precious seconds, this robot has one part that can be swapped within a split second It might be the difference...

(Two members of team Watt, and their robot)

MOT motor and NXT, this unit can be pulled and placed in all their base robots.

Here is a movie on how to do the full house mission.

I even spotted a FTC robot.

The next years theme will be ‘Smart Move’.


Feb 1, 2009

Wheels, Wings and Waves - Exibition in Vancouver, B.C. Canada

Yep, this one is a bit late but there is time left to join the fun! There's an exhibition at the Science World center Saturday & Sunday Feb. 1 from 10 a.m. to 3 p.m. featuring a new display "Wheels, Wings and Waves - a LEGO World of Transportation". Visitors can help Robin Sather (a LEGO Certified Professional) build a giant Space Shuttle this weekend which will remain as the focal point of the new exhibit. Visitor details may be found here.

I'm expecting some additional NXT News to come out of this, but it's on the slow wagon.

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