Edit: I first posted this early in the week - but took it off immediately as it had an HTML error - which is now fixed.
Mar 27, 2009
Edit: I first posted this early in the week - but took it off immediately as it had an HTML error - which is now fixed.
Mar 26, 2009
The book starts with a few pages talking about what datalogging is & how it works, and then just a very brief review of the built-in datalogging environment of Educational version of NXT-G 2.0. At the end of the book are a series of handouts and worksheets for the students, saving the teacher the time of developing these themselves. But the bulk of the book is a series of chapters organized by sensor: datalogging with the touch sensor, datalogging with the light sensor, etc, including the new temperature sensor. Each chapter starts with a description of the sensor, and what sort of readings it yields, before using it in a couple of experiments. Many of the experiments even come with a series of guided questions, including sample answers that students might generate. Chapter 8 steps up to experiments using more than one sensor, and shows some new ways to coordinate them.
On the whole, it's a nice set of simple hands-on experiments. There are some that kids will get a big kick out of (some that depend on human behavior of their fellow students), and some that teachers might value because they move towards even more sophisticated topics like physics (like building a "timing gate" with two light sensors). Some of them like, "The Bouncing Ball", are excellent examples of using datalogging to monitor something that otherwise would be very difficult to measure by other means.
There were some things I found to be a problem; for the most part they weren't due to the book, but due to the tools and the setting. Datalogging under NXT-G 2.0 is very easy, but it has some serious limitations as well - since it just logs the sensors, things like recording a series of touch sensor presses is poorly handled. For experiments like this, the students need to go over a graph of the data to manually record each push and the time they happened at. Here, using the built-in environment ends up making more work for the students, not less. The datalogging environment doesn't log as fast as it could (useful for some things, like the "bounce" experiment), and there's no real discussion of the memory limitations (why you don't want to log every 2 seconds for a week). In short, some of the experiments would be easier and make more sense if the students didn't use the new environment at all, but spent some more time understanding what they really needed to record... and how to do it.
The only other thing I had a problem with, is that the experiments seem too simple... there are a lot of other options, alternatives, or directions to take these experiments in, that I found myself asking "but what about...?" often while reading it. But that's not really a problem with a book; in some ways, it's one of the strengths of the book. Here Damien Kee has laid down the basics in a way the a teacher can adopt very easily, with very little effort - yet it opens up a world of possibilities for both the students, and the teacher, to take it much further. Here's where the real strength of this sort of workbook lays: in opening up the NXT to practical experimentation for people who haven't had the chance yet.
Teachers, you'll like this one, especially for grade-school kids and tight time budgets.
Mar 24, 2009
My son and I just completed his science project which involved LEGO and PF motors. Our exploration was called "Can you train a chicken?"
Mar 22, 2009
It has 7 degrees of freedom, and can walk up a step of 1.5 inches in height. Notice how it moves the NXT's from left to right to shift the centre of mass over the supporting foor.
Mar 20, 2009
"It's a robotic marble machine that propels marbles around a track, using many different ways of moving the marbles up, down, and around. It was made over the course of 4 days, much of the time figuring outs different ways to make the marbles move around. The final design (many tests and prototypes) includes steps, treads, and slides."
Check it out here.
Mar 19, 2009
When I started the project I was not sure what sort of lights to use - some are easier to use with NXT. Some are so bulky it simply does not go with the model.
The next lights I tried was the PF lights that came with the new LEGO TECHNIC off roader. The lights were very elegant and fitted neatly inside the standard hole. It was perfect. However I was not sure how best to interface to NXT. First I tried connecting it directly using the adopter:
Mar 17, 2009
Let's give him (or her) some encouraging--and constructive---feedback.
Mar 16, 2009
MCP Philo, well known for a lot of exciting robots, deep insight into the NXT internal electronics and as author of many LDraw parts and of a NXT book (just to name a few things), has published a new fascinating device: a NXT-based 3D scanner.
It scans small objects using a needle mounted on a LEGO® linear actuator and reports the data to a computer where they can be used to generate a related 3D CAD model:
Note that the scanner has been programmed with pbLua, the NXT programming language based on Lua.
A lot of more information can be found on the associated web page.
Mar 15, 2009
It occurred to me that (apart from approaches that use PC remote control) it might be a good strategy to create a NXT-based Bluetooth remote control that allows for separate control of each motor independently.
And here it is: the NXT Switchboard.
The program that actually runs on the robot in development (presently implemented in leJOS NXJ, the Java platform for the NXT) is a general-purpose one (it simply receives and handles the control signals sent by the remote control) and can be re-used for each robot.
Of course, one can use the NXT Switchboard also to remotely control finished robots (if required).
Addendum: in the video, the hand wheels are operated by my invisible Chesire Cat ;).
Mar 13, 2009
I wanted to share some tips that I have found in my experience with Lego Digital Designer(LDD):
I build in a sequence that LDD will work with. I have noticed that LDD does not build in true regular LEGO units. Instead, when you place a piece, it is placed very close to a true unit. Over time, these slight variations will add up to a point where you will not be able to align parts properly. This could be observed as not being able to put a peg in a beam, or not being able to place an axle. The rotation feature will make the most error because it is continuous. This makes it very hard to align parts by using rotation because it is hard to see how far a part should be rotated exactly by eye. However, there are some work-arounds for this problem. One useful building schemes that I have found is to build from the outside in. If you are having problems setting something towards the outside of your model, build temporary scaffolding around what you intend to build. This helps to set the error at that particular build stage. Depending on the complexity of the model, this may work, but it is possible that it may just give you the same problem but in reverse towards the middle of the robot. Altering where you start building your model will have an effect on how and where the error accumulates. Another Way to build complex models in LDD is to build them in modules and then connect the modules together. Starting from scratch for each module prevents the error from accumulating to an unworkable level. Cut and paste works in LDD. If you have a file open containing a module, select it all, use the copy command, open the main file, and paste in the module to be placed.
- Jay “click-click” Kinzie
Mar 12, 2009
Unlike some vehicle that uses wheel-lean to steer the vehicle (e.g. the Dodge Tomahawk), the wheel lean is used to aid the operator achieve a perfect grading finish: when the blade is at an angle, it helps keeping the grader pulling in a straight line. The top of the front wheels are normally leaned in the direction that material comes off the moldboard. You can find out more from this site [Thanks to John Brost for the link].
[And please remember to press the new HQ button on the YouTube video to watch the video in high definition.]
The Design process:
My second attempt used some of the new components that shipped with some of the new 2009 TECHNIC models - namely the wheel braces. However, I removed the front wheel drive motors as it impacted the steering accuracy. And talking of accuracy - I replaced the PF motors + clutch with NXT servo motor (with built in rotation sensors) - so I have fine control over the lean of the two wheels:
The finished design worked beautifully achieving 45 degrees lean either way. The leaning had an impact on the turning circle - making it smaller (see video above):
Today we are going to look at the actual Motor Grader, and see how best to robotize it. This will involve making some compromises as we balance great looks (faithful to the actual vehicle) against NXT functionality and constraints imposed by the TECHNIC pieces.
A new Motor Grader like the caterpillar M series (with joystick control) pictured above are extremely advanced and cost up to half a million dollars with all the attachments and add-on's. The add-ons such as AccuGrade (grade laser that takes away the need for survey stakes you see on road constructions sites) and other electronic kits (GPS, ATS, Cross Slope and Sonic kits) enable the vehicle operator reach perfect grade finish with least number of passes. Motor Graders are also probably the most complex of the construction machines to robotize.
- 5 motors / 4 linear actuators for the front wheels (providing power, active suspension and 3-d steering)
- 5 motors / 4 linear actuators in the middle to control the moldboard (providing four degrees of movement for the blade)
- 1 motor to control the articulations between the front and the back
- 2 motors / 1 linear acutator to control the rear attachment
- 4 motors for the rear dfferential drive control / wheels
- 2 PF battery packs and 2 NXT bricks.
- 1 IR-Link sensor
You read the title correct. He's in Antarctica this time... Waaay down under at Davis Station! See the sites and read the news of his visit on LEGO MINDSTORMS' homepage. There's a bunch of interesting information about Davis Station out on the web. Maybe some of the particulars about this visit will be added in the comments.
Mar 11, 2009
In ten days, on 21st of March, the RobotChallenge 2009 will take place in Vienna (Austria). According to the organizers it is the "biggest competition in Austria for self-made, autonomous, and mobile robots":
"The RobotChallenge offers suitable contests for beginners as well as for experienced robot designer. In addition to the possibility of exchanging ideas and innovations within an international group of participants there is also an excited audience as reward for the months of work in the area of informatics, electronics, mechanics and artificial intelligence."
There will be several interesting contests, including robot sumo, slalom and sprint competitons for humanoid robots.
Vienna is always worth a visit, and with this event, even more.
NASA have collated a enormous collection of Robotics activities to use in the classroom. Activities are designed for a variety of different age groups and abilities.
It looks like it has not been updated for a few years, and the majority of activities are designed for use with the older RCX, but there is no reason you couldn't modify them to suit the NXT.
If you're a teacher, have a look through a few (there are 300) and let us know in the comments which one is your favourite.
My favourite is "Junkyard Wars: Mechanical Monsters" Date Posted: 12.27.04
Mar 10, 2009
If you are living in Europe (or are going to visit it), mark end of June red in your calender: on 27th and 28th of June, Fana'Briques will take place again in Rosheim in the Alsace (France). It's one of the biggest LEGO® events in Central Europe; this year, it will be centered around the topic "LEGO® basketball".
Everyone who has been there already (including me), will certainly come back.
Who hasn't so far: it's absolutely worthwhile - nice athmosphere, tremendeous surroundings, interesting people, heaps of fascinating LEGO® stuff.
By the way: for exhibitors, registration is open now.
Mar 9, 2009
Mar 8, 2009
Did you ever want to know how fast your reflexes were?
This little device can measure how quickly you can react to a 'beep'.
Here's how it works:
- Turn on the NXT and press the button
- A random length of time (1-5 seconds) elapses and then a short 'beep' is played
- You need to clap your hands as soon as you hear the beep
- The time between when the 'beep' is played and when the clap is heard is recorded
- This time is then converted into an angle (0 seconds = 0 degrees, 0.9 seconds = 180 degrees)
- This angle is sent to the motor, which pauses for 2 seconds before returning back to the start.
- If you take too long (more than 0.9 seconds, the device makes an error sound and no time is displayed)
I remember keeping Chemistry and Physics lab books in college, and the rules were fairly strict and part of our grade was based on a review of our book(s) at the end of semesters. No pencil, of course - everything was in ink. A torn out page could get you an automatic letter grade loss, no kidding.
Still, it's an interesting article and maybe someone can come up with a version of the checklist for teachers/coaches.
Mar 7, 2009
Ever wanted to see a First Tech Challenge Final?
Now, here is your change, today there will be a live broadcast, from Den Haag, the Netherlands.
Today, you could have seen between 10:30 and 17:00 (CET), at this link: FTC-Nederland live
You can also visit the final, the entrance is free.
Winning team "Dinges" with their robot.
More information (FTC Dutch)
More information (FTC English translated via google)
Mar 6, 2009
This got me thinking recently about our LEGO NXT kits... and about the new WeDo kits. Given availability, many kids are now able to start tinkering with robotics at an even younger age. LEGO has provided a kit that will allow a teacher or parent to gauge a child's interest in computers or robots or programming. My son already can't keep his hands off my laptop keyboard and has figured out that dragging his fingers on the touchpad moves the mouse pointer on screen. He's not even 2 yet.
There are other subjects that I believe kids should be introduced to - art, music, history, and more. And each of these subjects probably have their own methods for introducing and encouraging kids to learn more. But we're talking about technology here - specifically, robots. So it makes me wonder how I can use my computer and robot kits to make learning more fun and more supportive when he needs extra help.
It's coming - I can see the day when a child has their own personal robot that imprints on them... follows them, maybe... and is always challenging them with questions and providing some answers. With the development of advanced WiFi technologies, the day is near when Internet connectivity with all devices will be "always on" so access to Wikis and other sites that can provide questions and answers will be a nanosecond away from a robot going out and grabbing a response to a child's query. Text-to-Voice (and vice-versa) conversion is here, but not great, but there will be breakthroughs in that area as well as voice detection and parsing of statements and questions.
Personal robots have a long way to go, but the technology is also moving so fast. I believe we're going to be shocked at the development or robots over the next 10 years. My first computer, the very first Apple Macintosh, had a floppy drive, no hard drive, b&w screen, and a single-button mouse. That was in 1984. Now, 25 years later, my laptop is more powerful than 500 of those Macs put together - and remember, 1984 was pre-Internet. The Dark Ages of computers is over... (can be argued, of course)... now we're going to start seeing robots being developed for all kinds of roles and not just as toys and heavy manufacturing solutions. They're primed and ready to start filling in the other areas of our daily lives - commuting, cooking, cleaning, etc.
It will be interesting to see what the LEGO MINDSTORMS 2020 version looks like. It's only 11 years away, but with all the breakthroughs that are occuring, I'm certain that a RIS owner from 1998 wouldn't recognize it if they had a glimpse. Maybe the next wave of robotics kits (LEGO and non-LEGO) will be for kids to build their own personal learning companion and tweak its outer design to their own style - the operating system and software will "wake up" and the robot will begin to teach its new friend as it begins to learn, too.
Mar 4, 2009
Thanks to John Hansen from NXTasy for pointing this out.
After I insulted my NXT for being physically inferior to my cat in just about every way, it sulked back down to my den and contemplated its next move. Hey, what if it stole a play from the cat's book, and tried striking quickly with a claw?
This Claw Striker robot uses the ultrasonic sensor to turn around and locate a target, move to the proper range (forwards or backwards as necessary), then strike quickly with it's claw-tipped whip-like arm.
Here's a video. No, it's not brave enough to take on the cat yet, even if I would let it (please don't try with yours either).
Mar 3, 2009
Mar 1, 2009
Next to a lot of black TECHNIC parts, I used three original NXT motors; as there are no black ones, I spent some effort in both hiding them from the view of the user as well as integrating them into the general scheme of the raven (with the intention not to spoil the overall bird-like appearance).
The Raven also integrates a sound sensor and is programmed presently to react to loud sound events. Hence it might sit on the top of the wardrobe at night and scare away visitors ... ;)