Author Reply to Book Review: The Da Vinci Invetions Book
Thursday, July 19th, 2007
A few days ago I raised some issues concerning Matthias new book “Advanced NXT: The Da Vinci Inventions Book” in my book review. I asked Matthias for comments on these issues, and I hereby attach his comments exactly as I got them:
“Guy, thanks for your review of the book and the overall good rating. I agree with you that the usage of parts that are not contained in the NXT kit may prove as some initial obstacle to readers of the book who do not possess other LEGO material than the kit. Yet, with some
creativeness, most of these parts might be replaced by NXT kit ones (for instance, the kit’s turntable can be used instead of the old-style turntable you mention for the Revolving Bridge). As stated in the book, there’s a particular book-related page on my own web site
at http://mynxt.matthiaspaulscholz.eu/book/index.html, where people can find media related to the book. Amongst other things, for each model there’s a list of parts used that are not contained in the NXT kit, alongside to links in which sets to find them (almost anyone
stems from the NXT’s predecessor, the RIS 2.0 MINDSTORMS kit) - following an idea of your’s. 
This page(s) will also make for your wish of providing videos and detailed pictures for the models to help buyers of the book in managing the more difficult building steps (so stay tuned for material to be presented there in the next days and weeks). After all, I have
hoped to help out already in the book with rather detailed instructions, in particular on the more complicated parts of the construction process. Well, the models are rather advanced in the end.
As for the graphical quality of the building instructions: there’s always a trade-off between resolution in detail and size of the book. And one’s always only as good as the tools that are available (sadly, LDD 2.2 was not available then and it still has some drawbacks that
would have made it useless for the models in the book anyway). However, I don’t think the instructions are that bad (they have been created with LDraw) - I still consider them rather fine and useful for the builder. I should be pretty surprised if people would not be able
to build the models in the book just because the instructions are not comprehensible enough. If that is the case (and any reader is encouraged to tell me so then), I will be the first to provide help on my web site.
Last but not least, I consider the detailed discussion of the five presently most important programming environments that run run on the brick an asset of the book. I know of no other publication presently available that provides such a detailed way to compare these languages and IDEs with real examples and decide on their usefulness for one’s
own needs and preferences in terms of NXT programming as the book at hand does. If a reader consider them intimidating then, it helped him to make a decision after all that this kind of language is not his cup of tea, dosn’t it?. Of course one could have provided the code on a web site only and leave it out of the book - but in my opinion, that appeals to the
content of almost any book: you can always move it from a book to a web site - but what would have been the use of the book at all then?
Sorry for having made so much words, and thanks again for your review and having given me the opportunity to make some remarks,
Matthias Paul Scholz (proud member of nxtasy.org for a long time already)”
Thanks, Matthias for your comments and for making the extra material available for the readers!
Guy Ziv
NXTasy.org
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Book Review: The Da Vinci Inventions Book
Monday, July 16th, 2007
A few days ago I rechived a review copy of the new APRESS book ‘Advanced NXT: The Da Vinci Inventions Book’ by Matthias Paul Scholz. After a few days, I finally managed to read through the whole thing (but didn’t build any of it’s designs, for reasons explained below).
Bottom line - it’s a good book, especially if you are looking for fully detailed building instructions and programming instructions. The book covers 5 of Da Vinci greatest works - the armored car, the catapult, the revolving bridge, the aerial screw (known by mistake as the ‘helicopter’) and the flying machine. Each work is described in a chapter of its own with historical background, discussion of the particular LEGO challenges and mechanisms used, full building instructions and programming details in NXT-G, RobotC, NXC, pbLua and leJOS. Before getting into the detailed codes, a nice diagram explains the program flow. Paul also gave good introduction to NXT and Da Vinci, as well as nice outlook on future improvements one can attempt for the 5 models, and two other Da Vinchi inventions which may be attempted by the reader.
Having said allready that this is a good book, it does have some drawbacks. The major one, for me at least, was the use of many pieces which are not part of the Mindstorms NXT #8527 retail kit (or the #9797 educational base set). Unfortunatly, the book does not give alternatives using the parts in the basic sets parts, nor give any indication which extra sets are needed and where to buy them. Some models use hard-to-get parts, like the revolving bridge which uses the old-style turntable (Peeron #2855 and #2856). Unfortunatly, I could not build some of the models due to lack of pieces…
Paul gives programming instructions in five different languages. Alltough some will find this an excellent way to learn new languages by comparision, I think it is not important. One could have, for example, put all the extra codes online, leaving only NXT-G (and maybe RobotC) code in text. For young readers, these detailed textual codes would probably be somewhat intimidating.
Another nice-to-have feature which I lack, is an online page with more pictures and videos of the machines in action. I think this would help understand some of the more difficult constructions steps, and especialy the use of strings in models such as the revolving bridge and the flying machine.
Last, as in allmost all black-and-white books with building instructions, the graphical aspects are problematic. In some figures the casted shadows distracts the eye, while in others the pieces are too reflective and some even appear to be transparent! I know how hard it is to make publication quality building instructions… I just hope a better solution will come up soon (and with the release of LDD 2.2 it may be close, even though it still lacks a lot more Technic pieces and other features to be a good candidate to replace good old LeoCAD/MLCad).
Guy Ziv
NXTasy.org
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News of the Month!
Thursday, May 10th, 2007For those who are not very familiar with the nitty-gritty of the NXT digital I2C bus, I wish to highlight the significance of the ‘Homebrew NXT port expander’ published on NXTasy.
As many have experienced the major limitation in the NXT is the number of sensor and motor ports. The only solution so far was using another NXT, communicating with Bluetooth with the first NXT (or RCX communicating with other means, like published a while ago). HiTechnic has been developing an active sensor multiplexer for some time (a picture of the prototype is here). This multiplexer will allow connecting 4 sensors – either passive (e.g. touch sensor), active (e.g. light sensor) or digital (e.g. sonar), to a single NXT port.
The solution presented by xw25adc is different – his port expander connects in series just the four ‘digital’ wires from the 6-wire NXT port – the +4.3V, the ground and the two digital I2C wires. Well, I’m getting too technical… Let’s stop that.
So what this so innovative about xw25adc work? To connect more then one digital sensor to a one port (i.e. a common ‘I2C bus’) you must have the sensor recognize that other sensors are connected. Why? Because the total of all sensors’ pull-up resistors must equal 82kOhm. If you naively connect two digital sensors, the pull-up resistance equals to two 82kOhm resistors in parallel which gives 82kOhm/2=41kOhm and the sensors will not function.
Anyone who read mindsensors.com manuals might notice a feature called ADPA: Supports Auto Detecting Parallel Architecture (ADPA) for sensors. This means that ACCL-Nx can coexist with LEGO or third party digital sensor on the same NXT port. This enables user to employ several sensors on the same port without the need of external sensor multiplexer, reducing the overall size.” This feature is just what one need to solve the previous problem – activating the ADPA on mindsensors.com sensors (it is shipped turned off) make them sense and recognize if more sensors are wired to the same port, and change the pull-up resistance to compensate this. xw25adc MUST have activated the ADPA feature, and used the compass sensor “advanced” I2C commands to change his ‘address’ from the default value 2 to 4. As far as I know, this is the first demonstration of this feature in action. Now some may ask - Wow! Can I do it too? Well, I can tell you that mindsensors.com have a prototype of a similar port expander in hand. In a few days I will post an image of this prototype when it reaches me. I’m currently working on a simple PC/Mac application that will ‘manage’ sensors – change ADPA on and off, change address etc. If I get some help from Lego/NI this application might even incorporate into the ‘Tools’ menu in NXT-G (no promises…).
One final technical detail – what differs between HiTechnic sensor multiplexer and mindsensors.com multiplexer? The former also allow connection of passive and active sensors, while the later supports only digital sensors (actually, only digital sensors which do not require 9V supply). This requires active components to regulate which sensor’s analog readout is transfer to the NXT at any moment. For these reasons, the HiTechnic multiplexer is expected to be more expansive (and it require 9V supply) then the passive mindsensors.com ‘I2C expander’.
Guy Ziv
NXTasy.org
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NXT in TIME
Monday, November 6th, 2006
The LEGO Mindstorms NXT makes it to TIME Magazine this week in a brief review — probably due to its popularity this holiday season.
I’ll never forget that Christmas morning in 1984 when I got the mother of all Lego sets, the medieval castle, and how happy I was snapping the colored pieces together to build it higher and higher. So it was a special treat for me to open up the latest iteration of the Lego franchise, a sophisticated system of sensors, motors and computer controllers called Lego Mindstorms NXT.
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LEGO Mindstorms NXT Education Software
Friday, November 3rd, 2006
Anthony Dhanendran from Computeract!ve reviews the LEGO Mindstorms NXT education kit.
Good points
* Great way to learn about basic engineering and programming
* Plenty of fun
* Easy to programBad points
* Can be complicated for younger children
* An expensive toyOverall
If you can justify the cost, Lego Mindstorms NXT is an extremely fun and educationally minded toy.
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Robots on the Dinner Table
Wednesday, October 25th, 2006
The Globe and Mail has published a well-written review of the LEGO Mindstorms NXT.
The Good: The sophisticated evolution of the classic children’s toy that can keep the young mind’s creative faculties focused
The Bad: The price; it needs a lot of space to spread out; the wordless diagram instructions aren’t always clear; it comes with no batteries (gasp!)
The Verdict: If you’re all grown up now, it’s the toy you wish you’d had when you were a kid. If you’re still a kid or a kid at heart, or have a kid that likes to tinker, Mindstorms NXT is the pinnacle of fun
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The Tourist — A mindsensors.com PSP-Nx Review
Saturday, September 23rd, 2006
Thanks goes to the kind folks at mindsensors.com for sending me their new PSP-Nx Sony PlayStation 2 controller interface for the LEGO Mindstorms NXT. I wanted to give the interface a spin and post a review, so I put together a simple robotic vehicle that I affectionately call the Tourist (click here for hi-res). Is the PSP-Nx a stud or dud? See the full review after the jump to find out!
Posted in nxtasy, hardware, reviews | 29 Comments »
Meet Dave Astolfo’s Tiltbot
Saturday, September 23rd, 2006
Fresh on the heels of DominoBotNXT, our good friend Dave Astolfo does it again with another excellent creation that he calls Tiltbot! He started this project to test and review the new Techno-stuff Tilt Sensor. Can’t wait to see a video!
The general idea was to build a robot that would navigate over varying terrain (eg. a few books etc), with a high center of gravity so that it could easily flip forward or backward. Then, to have the center NXT brick unit (seen in picture) to auto level itself to ensure that the robot weight was balanced and not flip over. The Tilt Sensor would allow for it to detect when it was riding up on an object and then shift the NXT unit forward or back depending on where the weight was shifting.
Learn more about Tiltbot over at Dave’s site: http://www.astolfo.com/
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PC Magazine Reviews LEGO Mindstorms NXT
Saturday, September 16th, 2006
Lance Ulanoff of PC Magazine gives a pretty extensive review of the LEGO Mindstorms NXT as he takes it for a spin with his 11 year old.
Bottom Line:
LEGO Mindstorms NXT is an excellent upgrade to an already worthy robot-building kit.Pros:
Well-built. Easy to follow instructions. Fun and learning for all ages.Cons:
Some instructions are all visual. Similar-looking parts can lead to confusion. Bluetooth lacks detailed instructions.
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Pocket-lint — “We love it.”
Monday, September 11th, 2006
With the LEGO Mindstorms NXT finally available in the UK, Pocket-lint got the chance to give it a good spin and has published a review. They love it, giving it a 9 out of 10 rating.
Lego has managed to create the perfect balance between a hardcore robotics kit and kids play without loosing [sic] focus along the way.
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IGN on Mindstorms Evolution
Thursday, September 7th, 2006
IGN has posted a brief article on the evolution of LEGO Mindstorms. The article is pretty much all fluff — sorta like this post, I suppose.
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First Looks: HiTechnic Compass Sensor
Thursday, August 31st, 2006
I’m a HUGE fan of Filip’s writing over at bNXT. He has recently updated his site with a great preview of the new HiTechnic compass sensor.
The new HiTecnic Lego brick adds value to my NXT set, and I believe sensors like these will bring more people to buy the LEGO MINDSTORMS NXT set. Users will have a wider range of sensors to build robots with. So everyone wins.
- Filip Verhaeghe
Likewise, Brian Davis over at theNXTStep has also given its readers a first look at this exciting new sensor.
I took a HiTechnic compass sensor and mounted it on JennToo, and then went ahead and wrote a program to keep the compass sensor pointed due south. The result is a fun and impressive robot that consistantly points in one direction (it’s a $250+ compass… OK, I need to make something more practical someday).
- Brian Davis
As you’ll notice in both articles, Filip and Brian highly praise the seamless integration of LEGO and HiTechnic hardware with this compass sensor. I wholeheartedly agree and cannot wait to see what else is on the horizon as the result of this terrific collaboration.
REMINDER: After all this praise to the new HiTechnic Compass sensor - the winner of the NXTasy Challenge will get one of these new sensors free of charge from HiTechnic! Click here for details.
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Brainier Robots, Brainier Kids?
Thursday, August 24th, 2006
Do children of today’s generation need ‘brainier’ toys to spark and maintain an interest in engineering and sciences?
BusinessWeek’s Stephen Wildstrom explores this idea in a new article on the LEGO Mindstorms NXT.
“Today’s leading high-tech toys are video games,” says Wildstrom, “which mostly give children vicarious training in handling automatic weapons.” He adds, “LEGO Mindstorms NXT could be a helpful antidote.”
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