Oct 31, 2007
Previously I had datalogged by just grabbing a reading and storing it in a file as quickly as possible. But for a 5 minute ride the resulting file would be large - so large that I could only record one or two rides a day. Instead, the program stores the average value of the three axis data, with the sampling interval selected by the user at start-up. There were a few glitches, but overall this method worked great. If anyone wants a copy of the program & instructions on how to use it, let us know, and I'll try to pretty it up and post it (teachers, students - does this look like something fun to do?). Usually, I wrote to the datalog about every 100 ms, giving 10th of a second time resolution.
The result is information on not just the "max G's" that the rider pulls, but a more detailed description of the ride. In these graphs, the thick blue line is the total acceleration on the NXT, derived from all 3 components. The acceleration directly down into the seat is shown in light blue - normally this is your weight (the higher the trace, the more you are pressed into your seat). The acceleration forward or back is shown in red (the higher, the more you are pushed against the back of your seat). Finally the side to side acceleration is shown in yellow (as you are pushed against the side of the car in a sharp turn, the side to side acceleration will become larger in magnitude). So for instance as you are pulled up the 1st hill at a steep angle, you are pushed against the back of your seat, as shown by the red trace increasing to a higher level. As you dive through the bottom of a steep drop, the acceleration smashing you into your seat increases dramatically. It really is amazing the details you can see in the data if you know the ride (I've labeled a few interesting points... yes, perhaps I've ridden some of these 'coasters a few times :) ). I'm not going to give away any spoilers here... but if you know the ride, see what you can identify in that graph. The purple trace in this particular graph is from a different ride, showing how the acceleration varies if you are lucky enough to get the very front seat (worth the wait, actually).
I was actually able to datalog several rides during our stay: at Animal Kingdom, I logged Expedition Everest, Kali River Rapids (missed the big drop however), Primeval Whirl (a "crazy mouse" style ride, with some fun spinning and a few notable drops with low-G sections bracketing them), Triceratops Spin (with my daughters in control). Within the Magic Kingdom, Big Thunder Mountain showed some impressive "negative G's" (really just low-G points: as the data shows, you are never actually thrown up from the seat), while Splash Mountain actually recorded the peak acceleration of anything I measured at Disney, hitting 2.5 G's at the bottom of the drop, and Space Mountain also revealing it's secrets. Finally in EPCOT, I logged Mission Space multiple times to make sure I got it (wonderfully smooth curve... and proof that even Disney hasn't quite got real "zero-G"), and my son was kind enough to do the brake testing section of Test Track.
If people want to see some of the other graphs, I'll pop them up in a further post. But mostly I just wanted to share with you some of the really cool stuff you can do with the NXT in an educational setting. Yes, that's right, I just claimed playing on roller coasters at theme parks is an educational setting. And I'm sticking by that. They are, when you can put the thrill rides into a context that people can understand, or get them to experience it in a new way - which you can do with the NXT, a simple sensor, and a program that a 10-year-old could write.
Now, I've just got to get back there to do some of the ones I missed. Like Tower of Terror (real "zero-G" on that one), Rockin' Rollercoaster (the initial acceleration should be very interesting), the Spinning Teacups (I love those things), & who knows what else. But for now, I'll leave you with a picture of a tired NXT, that has more than earned the right to a bit of rest.
Dang, it's hard work testing toys. ;)
Addendum: To try to keep things linked, I'm including the links to other datalogging blog entries here:
27 Sep 2007 Datalogging in a racecar
10 Sep 2007 Datalogging in NXT-G
14 Aug 2007 NXTlogger: a BT Datalogger
22 Feb 2007 Datalogging + Robotics
23 Nov 2007 Acceleration in the Community
Oct 30, 2007
During LEGOWORLD, I've built a NXT-driven gun that is based on the Zamor shooter from LEGO(R)'s BIONICLE series.
The shooter, named Nashorn (German for Rhino), is stationary and can be accurately moved in two directions, either autonomously or using a remote control (as I did in the following video).
For more pictures, see the robots section of my website.
Oct 29, 2007
Oct 27, 2007
This infrared electronic soccer ball is well balanced and emits infrared (IR) signals in all directions making it a great IR target that can be detected by the HiTechnic IRSeeker.
The ball contains 20 IR LEDs that are positioned to virtually eliminate blind spots and make sure the IR signal can be easily detected by your robot.
The ball is 75mm (~ 3 inches) in diameter and requires 4 AAA batteries (not included).
Here's a cute and cuddly robot from David Perdue's new NXT book, to be published next week by No Starch Press. The book's companion web site is here.
Oct 26, 2007
The R&D Magazine has announced the winners of its 45th Annual Awards for Brilliant Inventions - the "Oscars of Inventions", as The Chicago Tribune once called them.
"For 45 years, the prestigious R&D 100 Awards have been helping companies provide the important initial push a new product needs to compete successfully in the marketplace. The winning of an R&D 100 Award provides a mark of excellence known to industry, government, and academia as proof that the product is one of the most innovative ideas of the year. " (cite from the R&D Magazine)And: the LEGO(R) MINDSTORMS(R) NXT is amongst them! It's even listed as one of the 10 Most Brilliant Inventions the renowned InventorSpot has destilled from the winners.
"The results are incredibly diverse, spread out over 50 categories, including Energy, Environmental, Lifesciences, Process Technology, and Software, to name but a few." (cite from GearLog)
Congratulations (but well-deserved)!
The Reliable Plant Magazine has published an article in its September/October Issue on 10 off-the-wall projects to
"help get your creative juices flowing, here we look at 10 do-it-yourself projects that fall somewhere between remarkable and ridiculous. MacGyver would be proud."There are three NXT projects contained: Andreas Dreier's and Mike Brandl's Egg plotters and Will Gorman's RoboFlush.
Prominent neighboorhood: also Dean Kamen's Segway is listed.
Oct 24, 2007
Who needs an IR-Link to bridge between NXT and RCX when you got this?
The solution has an RCX light sensor reading the LCD of the NXT, and a NXT light sensor reading the IR port of the RCX. Impossible? You need to see the video to believe it!
More info on Leggor.de
Oct 23, 2007
The Chicago-area robotics club, ChiBots, held a competition this weekend called Chibotica. The competition was open to all types of robots, and there were several NXTs entered. The photo is of an NXT-powered line follower called Big Rig - created by Steve Hassenplug.
You can view photos here.
You can view videos here.
Objective: Move the Power Lines from base so that they're touching the Power Plant's property and the white of at least one surrounding community. Bonus for touching the white of a surrounding community that is touching a scoring Hydro Dam or Wind Turbine.
Point Worth: Up to 30 points
Mission Location: Top (North) edge of mat.
Estimated Difficulty Level: 2/10 for minimum points, 3/10 for maximum points (assuming Hydro Dam and Wind Turbines are in proper position)
Time Length Rating: Low
Unique Challenge Aspects: Amount of points recieved for this mission may depend on how the Hydro-Dam and Wind Turbine missions were completed.
This mission is fairly straightforward and uncomplicated. However, it does require some precision if you want the maximum points, because the Power Lines model has to be in a fairly small range of positions to be touching the Power Plant and the three surrounding communities. This may prove to be somewhat difficult for RCX teams that aren't using rotation sensors. This mission also requires some strategy and planning. To get max points, teams will need to coordinate the solutions of three missions - the Hydro-Dam, Wind Turbines, and this mission - so that the models invloved in them will be in the right positions for all the criteria.
Richard's Comments: Remember that the Power Lines must be upright in order to score. Just a reminder.
1) How each year's FLL Challenge is designed
2) How to Robotize the NXT with the new Power Function motors
3) A review of HiTechnic's new IR sensor and how to program it
(Numbers 2 and 3 above are written by NXTstep Blogger "BlueToothKiwi")
The new PDF issue of BrickJournal is available for free here.
Oct 22, 2007
Sunday on LEGOWORLD - one could guess that this is one of the days where people are virtually flooding in.
The Billund MINDSTORMS guys (Chief Steven, Technical Brain Flemming and Top Designer Joern) are off again for Denmark and have left not only some nice bags on our booth but also a lot of ideas for the future in our brains. Thanks to them again for their generosity. :-)
Daniel Wittenaar spontaneously made an NXT ape that clawed his way over their booth. Intriguing!
Sadly, my Zamor shooter that I built this morning to terrorize them did work quite well, but didn't make it over the distance. Have to work on that, though... ;-)
Ah yes: we sold all our copies from the Idea book.
Enjoy the pictures from my last day here - I'm positive that I'm going to feed on this experience for a considerable time.
Images (from top to bottom)
- Noteworthy things about the Bowling Lane
- Building contest winners
- The Bowling Lane in action
- Trains, trains, trains!
- Part Vultures
- The production of three days building (note Philo's remote control that I used to control the Zamor shooter - great gadget that has been admired widely here)
- World record attempt on quick building the "Millenium Falcon"
- Daniel's MINDSTORMS booth Ape
- Never underestimate the power of the Emperor
Oct 21, 2007
Wow, this has been a most memorable day on LEGOWORLD 2007 so far - masses of visitors and everywhere LEGO (R) builders discussing, building, presenting, inventing... an enormously creative and inspiring ambience.
Amongst a lot of other things, I noticed that Martijn not only is an outstanding builder but also a very skilled salesman of the Idea book... ;-)
Now the visitors are all gone, and the exhibitors' dinner is going to start soon - Steven is inviting the MCPs somewhere (and Martijn cares for the location).
Let the images speak for themselves.
Oct 20, 2007
Oct 18, 2007
Oct 17, 2007
Bot'oberfest was a HUGE success! Held this past Sunday (Oct 14) at The Atlanta Girls' School, the unofficial attendance was estimated to be over 350.
Classes included Intro to NXT-G, Intermediate NXT-G, Advanced NXT-G, Robot Design Basics, Chassis Design, and Attachment Design. We also had a Judging class where attendees could listen to and ask questions of Technical and Project judges. Energy experts were invited and talked and answered questions on a variety of subjects related to this year's FLL challenge. And, of course, there was a scrimmage area where some teams tested their robots.
We also had a room for students with snacks and drinks (another HUGE hit) and a room for teachers/parents/coaches with coffee and food. Key sponsors were Georgia Tech and the GT Women in Engineering program... LEGO Education was also fully supportive of the event and provided some giveaways. Finally, YES (Youth Engaged in Science) donated a $250 gift certificate that could be applied to any of its enrichment programs.
All of the organizers (myself included) went into this with the full intention of providing access to our notes and materials to others who might be interested in setting up a similar style event in their area.
Kristie Brown, LEGO Ed rep for this Southeast area, is hosting much of the material on her website - you can download slideshows and support materials used by many of the presenters here.
LINK for emailing: http://legoeducation.typepad.com/georgia/botoberfest-2007.html
The feedback we have received so far has been overwhelmingly supportive. Thanks to all of you who attended and we hope you had a great time.
The Chicago-area robotics group Chibots will be hosting Chibotica, a robotics competition, this Sunday from 10 a.m. to 5 p.m. at iHobby Expo at the Donald E. Stephens Convention Center in Rosemont, IL. They will also be hosting demonstrations that are open to the public on Saturday. There will be a LEGO Sumo competition, in addition to several other competition categories that are open to other types of robots. You can view more information on the competition here. Look for them in booth 2202.
NXTs should be well represented as legendary MDP Steve Hassenplug is a member of Chibots and is scheduled to compete in several categories! If you'd like more information on the rest of the iHobby Expo you can visit here.
Check it out here.
Oct 16, 2007
You can also see a NXTLog of ScanBot here.
Oct 15, 2007
Do not forget: next week on Thursday the LEGOWORLD 2007 starts in the Ijsellhallen in Zwolle, Netherlands (about 100 km from Amsterdam). This event, one of the largest LEGO related ones in the world, will last until Tuesday the 23rd.
From the hosts:
"Are you curious to know what the first LEGO toys looked like? Then come visit the LEGO Museum!If you intend to visit, do not forget to drop in at LEGO's MINDSTORMS NXT booth and the NXT booth opposite from it that is maintained by some of the Dutch MCP members and authors of this blog.
Experience the new story in the underwater world of BIONICLE.
Learn how to build your own robot at the MINDSTORMS NXT demonstrations.
Race along with LEGO Racers
Have a look at the 1:1 LEGO Ferrari that can actually drive."
I will be there also and am going to report some kind of LEGOWORLD diary on this blog, given that I'm able to get regular access to the web.
See you at LEGOWORLD. :-)
Oct 14, 2007
Good news, everyone! (in my best Professor Farnsworth voice)
At least for those amongst us who are into programming their NXT with Java, in particular with leJOS NXJ: there's finally an Eclipse plugin available that in an integrated way allows to upload the firmware and to develop, compile and upload NXT Java programs to the brick in Eclipse (the most popular Java IDE presently around, and justifiably so).
Based on the latest leJOS NXJ release, it supports the most recent Eclipse version 3.3 (Europa), thus runs on Windows and Linux.
Use Eclipse's Update manager to install it from the remote update site as follows:
Name: leJOS NXJ (or whatever you like)
For configuration and usage, consult the leJOS NXJ topic in Eclipse's Help->Help contents view after installation.
Give it a try and provide feedback.
Oct 12, 2007
This kid-friendly book will be published by No Starch Press in February 2008. It has step-by-step building instructions for nine animal robots, complete programming instructions for each robot, teacher's guide, troubleshooting guide and a guide to making animal sounds for your robots.
Oct 11, 2007
John Hansen, the author of NXC, a C-style programming language for the NXT that runs on the original NXT firmware on the brick, has announced that Variant Press will soon publish his new book,
NXT Power Programming. Robotics in C.
It can be pre-ordered now at Amazon.com or Variant Press.
The author on his book:
"NXT Power Programming delivers everything you need to create the robot you've always dreamed about. This is the definitive guide to C programming by the developer of some of the most powerful and popular development tools for LEGO MINDSTORMS.I'm positive that everyone who has used NXC in the past as an alternative to the "official" language NXT-G will be anxiously awaiting the availability of that book at 7th of November (including me).
John C. Hansen presents a comprehensive yet friendly set of tools that allow you to create almost any robot you can imagine. Inside, youll find an ingenious set of projects that explore the complete arsenal of NXT functionality. At the heart of these projects is Versa, a versatile mobile robot platform utilizing modular attachments."
mouse over and use right menu to control clock ( also ctlr-f for full screen mode)
You can easily customize the view by
1) opening the main window
2) select timer in the list o the left
3) select "edit" timer settings
4) select the "font" check box instead of the skin (font =tahoma)
5) change the start countdown time to 2 min 30 secs