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The Unofficial Guide to Lego Mindstorms Robots 76

Quite a number of you out there are into Lego Mindstorms, as evidenced by the number of book reviews that have been sent my way. Below are a couple of reviews, one from Kurt DeMaagd and the other from Will Ware. Click below to get their take on the O'Reilly book The Unofficial Guide to Lego Mindstorms Robots.
The Unofficial Guide to Lego Mindstorms Robots
author Jonathan B. Knudsen
pages 247
publisher O'Reilly & Associates
rating 9/10
reviewer Will Ware & Kurt DeMaagd
ISBN 1-56592-692-7
summary Get the most out of your Lego Mindstorms

The Unofficial Guide to Lego Mindstorms Robots

Review by Will Ware

Last year, Lego released their Mindstorms Robotics Invention System. Using this, children and adults can build simple robots whose behavior can be programmed. The Mindstorms system is a major contender for Coolest Toy on the Planet.

The system contains a RCX programmable brick containing an H8/300 microcontroller, some pushbuttons, a little LCD display, and connectors for motors and sensors (light and physical contact). The user writes a program using a graphical programming language on his Windows box, and downloads it to the RCX via infrared.

Not surprisingly, substantial reverse engineering (1, 2) has been done by hobbyists, and it is possible to develop Mindstorms programs on a Linux box and to download the RCX brick from Linux.

Now O'Reilly has joined the Mindstorms fray, with a book full of fun and useful information about how to build and program Mindstorms robots. The book describes four different robots: Hank is a bumper car robot, Trusty uses light sensors to follow a line along the floor, Minerva has a movable arm, and two identical robots play a game called RoboTag. Along the way, the author discusses the physics and mechanics of robots, programming issues, and the available development environments for Mindstorms.

What's Good?

There are detailed building instructions for each of the robots, showing photos at various stages of construction. The designs are simple and appear mechanically sound. There are discussion of the physics and mechanics of tank treads, steering, gears, and other things.

The book's chapters sequentially step through several different software development environments. The first chapter starts with the Windows-based RIS environment that comes on the Mindstorms CDROM. Later chapters give programming examples for NQC (Not Quite C), pbFORTH, Visual Basic, and the legOS operating system, which uses an EGCS cross-compiler to target the H8/300. There are more development platforms available, but these give a good sense of what's possible in Mindstorms programming.

The book has dozens of useful URLs, for both official Mindstorm sites and unofficial hobbyist sites. I particularly liked the fact that the author was aware of some of the recent research in robotics. For instance there is some discussion of Rodney Brooks' subsumption architecture, which is used for the RoboTag robots.

Later chapters of the book often expand on designs from earlier chapters, building more sophistocated robots in an accessible, incremental fashion. For the more adventurous hobbyist, the final chapter talks about building your own sensors and actuators, and how to connect them to the RCX.

What's Bad?

Some of the photos are too dark and lack contrast. It would also have been nice if the photography had been in color, but black-and-white photos kept the book more affordable.

This book is for the casual weekend robot-building tinkerer, and it never promised to discuss real-time embedded issues in depth. Still, a few topics might have merited at least brief mention. Systems with real-time multitasking must frequently arrange for synchronization and communication between tasks, using mutexes and mailboxes and the like, which brings the possibility of deadlocked processes. Another danger is that an aggressively efficient compiler will sometimes optimize away reads and writes to hardware registers. The fix is to declare such registers with the volatile keyword.

Review by Kurt DeMaagd

While Lego Mindstorms were officially released for a teenage crowd, they have become popular with a wide variety of technically competent people in many age groups. This widespread fascination has opened up a whole new world of opportunities for using Mindstorms. At the same time, the documentation and tutorial included with the Lego kits provide very little information about how to get the most out of the sets. This book fills the void by providing several start-to-finish robot designs, software to run them, and a wealth of other tips and tricks.

After a brief introduction to robotics and how Legos fit in, the author discusses the basics of using Mindstorms to create them. Both chapters present a problem, provide step by step building instructions, provide the necessary information to program the solution, and finally go into greater detail about the Lego features used to solve the particular problem.

While the chapters did an excellent job of presenting this information in general, they fell victim to a problem that would plague the entire book: some of the building diagrams were nigh unto unreadable. Attempting to build a robot based on fuzzy black and white photographs can be quite a chore. Fortunately, none of the robots were so complex that they robots were completely unbuildable.

The first few chapters presented robots programmed with the default RIS programming environment. In chapter four and following, he shows how to program using languages such as Not Quite C, Forth, Sprit.ocx for Visual Basic--or optionally Visual C++ or another ActiveX-aware language--and legOS. Since much of these sections was documenting API's, it was certainly not the most exciting read, but it does provide concise, easily to reference documentation.

Not Quite C, as the name implies, is a C-like language that can be used to program Mindstorms robots. It overcomes many of the limitations of the default RIS programming environment, most notably the lack of variables. One of its biggest advantages is that it does not require the user to install a new version of the firmware on their RCX unit. In general, it provides an excellent balance between power and usability.

The remaining three means of programming presented in the book are fairly mediocre options. PbForth requires the user to download a new firmware version, and the language itself is very archaic in modern software development terms. Using Sprit.ocx is a viable option for people used to programming in Visual Basic or Visual C++, but the control structures are very clunky and non-intuitive. legOS, while it is probably the most powerful option, takes a significant amount of time to set up and develop applications with.

Two of the projects referenced while discussing the various programming languages were particularly interesting, both of which outlined infrared communication. The first program creates a simple remote control for controlling a robot via the IR port on the RCX. The other example, perhaps the most interesting in the book, was creating two robots who played tag with each other. These two robots also communicated with each other via their IR ports.

The last chapter, targetted toward the hard core Mindstorms users outlined how to create additional sensors for Mindstorms. It sketched out such possibilities as a passive light sensor, a Hall effect sensor (magnetic fields), and a touch multiplexor (allowing you to have more touch sensors than normally allowed on the RCS unit).

In general, the book provides a vast array building and programming tips, tricks, and methods. He gives basic information for the person who is just starting, and introduces the advanced user to the vast network of people and product that have made Mindstorms far more than a child's toy.

Purchase this book at fatbrain.

Table of Contents

  • Preface
  • 1. Welcome to MINDSTORMS
  • What is a Robot?
  • Mobile Robots
  • What is MINDSTORMS?
  • What Now?
  • Online Resources
  • 2. Hank, the Bumper Tank
  • About the Building Instructions
  • Building Instructions
  • A Simple Program
  • Wheels
  • Bumpers and Feelers
  • Gears
  • Multitasking
  • Online Resources
  • 3. Trusty, a Line Follower
  • Building Instructions
  • Some Tricky Programming
  • The Light Sensor
  • Idler Wheels
  • Using Two Light Sensors
  • Online Resources
  • 4. Not Quite C
  • A Quick Start
  • RCX Software Architecture
  • NQC Overview
  • Trusty Revisited
  • Online Resources
  • 5. Minverva, a Robot with an Arms
  • Building Instructions
  • Programming
  • Directional Transmission
  • Pulleys
  • Mechanical Design
  • Two Sensors, One Input
  • Where am I?
  • Online Resources
  • 6. PbFORTH
  • Replacement Firmware
  • pbForth Overview
  • About Forth
  • pbFORTH Words
  • An Expensive Thermometer
  • Minerva Revisited
  • Debugging
  • Online Resources
  • 7. A Remote Control for Minerva
  • Two Heads are Better Than One
  • The Allure of Telerobotics
  • Building Instructions
  • Programming the Remote Control
  • Programming Minerva
  • Online Resources
  • 8. Using Sprit.ocx with Visual Basic
  • You May Already Have Visual Basic
  • About Spirit.ocx
  • Calling Spirit.ocx
  • Immediate and Delayed Gratification
  • Programs, Tasks, and Subroutines
  • Tips
  • Retrieveing the Datalog
  • Online Resources
  • 9. RoboTag, a Game for Two Robots
  • Building Instructions
  • Subsumption Architecture
  • Online Resources
  • 10. LegOS
  • About legOS
  • Development Tools
  • Hello, legOS
  • Function Reference
  • New Brains for Hank
  • Development Tips
  • Online Resources
  • 11. Make Your Own Sensors
  • Mounting
  • Passive Sensors
  • Powered Sensors
  • Touch Multiplexer
  • Other Neat Ideas
  • What About Actuators?
  • Online Resources
  • A. Finding Parts and Programming Environments
  • B. A pbFORTH Downloader
  • C. Future Directions
  • Index
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The Unofficial Guide to Lego Mindstorms Robots

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  • by ransom ( 115658 )
    If I had the money I'd go for it... maybe for xmas. How much does a starter set or whatever the beginning set is called cost? How hard is it to do it on Linux / where is a URL where I can read about it? I have a million legos already... If I can get a set of Mindstorms maybe I'll build a giant Godzilla robot and sic it on Japan! Who's in?

    If you think you know what the hell is going on you're probably full of shit.
  • i'm definately getting his little number for x-mas.... it seems like a good choice. especially if i get my lego along with it :P....

    carnage
  • Anyone that's thinking of getting Mindstorms should try to get a 1.0 box if you can find one. The RCX in the new 1.5 boxes dosen't have an external power jack! That's a real bummer if you want to do something that uses alot of power, without having to change the batteries often. The 1.0 boxes with the 1.5 upgrade stickers have RCX's with power jacks.

    (RCX is the programable brick)

  • I'm really interested in pursuing robotics as a hobby, and I'd like to start before my son is at an age where I'd be a useless partner (he just turned 4, so I have time.)

    Mindstorm seems like an interesting product but I'm wondering how it compares to more hands-on (dare I say, DYI) approaches like the one outlined in Mobile Robots (Jones et. al.)?

    Anyone out there have some grounds for comparison?

    --Paul

  • amazon.com has it for $199.99, and I think I've seen it at retail for the same price. (I'm a bit disappointed at amazon here - I'll have to try eToys).

    D

    ----
  • If Slashdot readers gave feedback to Lego, and showed them that a significant number of Lego Mindstorm (and Lego, in general) users use Linux, it's possible Lego might be a bit more active in supporting the OS.
  • by chromatic ( 9471 ) on Wednesday November 24, 1999 @04:42AM (#1506912) Homepage

    I'd like to second the idea that this book is an introduction to Mindstorms. It does have a lot of useful references, and serves as an overview of What You Can Do with Your Mindstorms. There's not a lot of time spent on any one topic.

    It would be nice to have another couple of chapters on more advanced topics ("Common Traps and How To Avoid Them", "Cool Hacks You'd Never Think Of", "a Beowulf Cluster of Mindstorms"). It's a good introduction, but don't expect a LEGO Camel.

    --

  • This has to be quick, but- for anyone who uses Linux, legOS is not at all difficult to setup or maintain. John Knudsen is a good guy, but he (and the target audience) are windows users. If you can get RH running, you can get legOS running. It is easily the best way to use the Mindstorms from Linux. Check out the homepage [www.noga.de] or my HOWTO. [duke.edu]
    ~luge (use it before you criticize, guys...)
  • I checked e-toys, same price. I think LEGO has a lock on how much they can charge for it.
  • My son is nearly turned 5

    Any /. parents (or loco parents / aunts / uncles / cousins etc.) care to discuss good age ranges for introducing kids to Mindstorms ? It's very easy to hot-house kids into small-parts Lego when they simply don't have the motor skills to assemble the more fiddly parts.

  • Does anyone know if the brick can meter the power level of the battery? I'd like to build a robot that can hook itself up to a recharger when it gets low.

  • Yesterday I was at the local 'Best Buy' looking at computer games. When I ran into a display containing mindstorm kits! The droid development kit was only 100$ (Only? Working with computers sure warps your reality.)
    When I get the time I'll consider getting one. Maybe during winter break.

    In all the sci-fi I've seen, I don't remember 'really cool toys' as part of the future. In retrospect, it's obvious. So here's my prediction, the future if chock full of cool toys.

    (Wonders how much a battalion of Battle Droids would cost.)

    Later
    Erik Z
  • I'd love to buy Mindstrorms for my kids (OK for me too .... but you see I'd have to 'buy it for the kids') but the big problem seems to be platforms - we're a Mac/Unix house, Windows was banished as neither kid or adult friendly

    Is there a (younger 8-9ish) kid-friendly mindstorms development environment for the Mac? how about Linux? - the adult/hacker level stuff I can handle for Linux (hell I SELL an open-source microcontroller kit that does many of the same things, with my own OS/SDK/...), but the easy-start GUI thingy would still be fun toi have around.

    Lego how about open-sourcing your GUI - let Linux people port it to their platform? - think of all the customers if Slashdot announced the Linux SDK ....

  • For the curious, the original RoboTag (on which the chapter in the book is based) is at http://www.mattdm.org/mindstorms/ [mattdm.org]. It's not quite as computer-science as Jonathan's version, but it works very well, and I like to think I've got a nice explanation of it all. Plus I've got cool movies.

    I haven't updated the web page in quite a while (other projects; you know how it is....). But take a look if you're interested.

    --

  • I'd love to buy Mindstrorms for my kids (OK for me too .... but you see I'd have to 'buy it for the kids') but the big problem seems to be platforms - we're a Mac/Unix house, Windows was banished as neither kid or adult friendly
    I believe you can run the robolab software in MacOS (robolab is the version of the mindstorm soft for schools) And if you can do C, legOS is the way to go...
  • This month's DDJ (Dr Dobbs Journal) also has a brief piece on the background to legOS

  • Some younger kids may be able NQC, with some help -- it's not really that difficult.

    MIT has a nice version of Logo that both has a GUI and is a complete, powerful programming language. I'm not sure if it runs on MS Windows, but definitely there's a Mac version. It's available to educators, but unfortunately not to anyone else.

    --

  • Slightly offtopic, but is anyone else here a closet K'nex user? I have had my share of Legos in the past and enjoyed every minute of it until I dicovered K'nex. IMHO, they are much more verstile, the "structures" or "designs" or whatever are extremely sturdy, and the variations are just as limitless.

    The one advantage that Legos have at this point is the MindStorms. K'nex only have a motor at this point which will "spin" pieces in a few different directions, but with a little creativity they are just as fascinating.

    I hope someday to have a web page with my K'nex creations, but until then the only decent site I have found yet is at http://www.balmoralsoftware.com/knex/ knex.htm [balmoralsoftware.com]

    Sorry, if this is too far off topic, but Legos seems to get a lot of press where K'nex have yet to be mentioned. Kinda like the Linux and Windows...

    Imagination is the foundation of reality -Gallagher

  • hey look, i left out some words. typing too quickly. that should read "Some younger kids may be able to handle NQC, with some help..."

    --

  • I've heard a couple people mention the Robolab system, which apparently is a more configurable version of the Invention System (correct me if I'm wrong). However, as far as I've been able to tell from Lego's website [lego.com], Robolab is only for schools. Does anyone know if Robolab is available to individuals, and if it is worth checking out over the Invention System?
  • The Droid Developer kit does NOT come with the RCX. It comes with a "Mini Scout" brick that has no method of updating the software on it. It has 5 or 6 fixed programs, and that's it. It looks really cool, but you do get shortchanged in the programming department.
  • My son is 12 and my daughter 7. They love to play with Legos and have had some fun with the Mindstorms set. The problem is that we own several large containers of Legos and right now one of our touch sensors is lost in one of these containers!

    My son has been coding since he was 10, so he has no problems writing Mindstorms programs. I would let him play with the set more, if he didn't spread all the parts from one end of the house to the other... ;-)

    ...richie

  • My co-workers bought me a K'nex kit as a going away present for my last position (as well as a CompUSA gift cert!!!).

    I tried it a few times, but I just can't get into it, I still prefer Lego. If I'm gonna build something K'nex like, I'll just break out the Technics.

    Any ideas on how I can get more into K'nex?

    George
  • It's by the author of the system, Markus Noga. A very sharp cookie, I'd say :)
    ~luge
  • I was wondering if anyone could tell me if these are worth getting or not. I've been thinking about asking for these for Christmas, but I was wondering if they would just end up in my closet collecting dust.

    They sound fun but I don't know if I'd ever get the time to play around with them(I work and go to school).

    Thanks
  • Mac NQC works on PowerMacs and works with most USB serial widgets. Mac Robo Lab is ok, but hard to get outside of the USA.

    Using Emulation (VPC etal) and MindStorms Software on the Mac you will need get or to make a Powered Break-Out-Box.

    Quick Hardware notes:
    Yellow RCX 1.0:
    The Original and the Best. Get a 1.0 box if you can and upgrade to 1.5 later. As said already 1.5 missing Wart-power.

    Blue RCX, aka Scout:
    OK, has a remote, missing an Output and has Internal LightSensor Block. Great with a MicroScout.

    MicroScout (Droid Kit):
    Best "Out of Box to Play" time of the whole line. 6 Hard Coded programs and no user program space. CD is a Building Guide and no IR tower.

    Have fun

    PS: RCX owners get Free Web Page on Lego Site. (for lego releated only).
  • Looks like O'Reilly is really expanding their coverage of the geek spectrum. First the user friendly comic book (which I even saw in the leisure reading section of my school's bookstore) and now this.

    _joshua_
  • by luge ( 4808 )
    Yeah, the price is pretty fixed at around $199. On the other hand, if you already have a ton of technic pieces (gears and such) and don't mind not having the official lego software (which is lose95/98 anyway) you may be able to save a little bit by getting the RCX unit and sensors separately. Try the lego world shop [legoworldshop.com]. I'm pretty sure they have them separately.
    As for software, well, with Linux you are pretty much stuck with PBForth [bmts.com] or legOS [www.noga.de]. Both of those are going to require a language (forth or C, respectively) but are going to be much more powerful than the standard software.
    ~luge
  • I see DeMaagd and instantly think Dave. Oops...
  • There is an introductory kit called the "Robotic Discovery Kit" that comes with a processor called the Scout. The Scout doesn't require a PC to program -- it comes with a builtin, more simplistic function set, and builtin programs. The Droid kit also uses the Scout.
    --
  • Yeah, you can meter battery power. However, it runs on standard AA batteries, so you can't really recharge it unless you could build a 'bot that disassembled itself.
    ~luge
  • by luge ( 4808 )
    Don't get fooled by the scout, either. Again, cheaper, but connectivity to the computer is limited at this point (though Lego appears to have hidden more than a few tricks in it's software.) If you can at all scrape up that extra hundred bucks, buy the "real" Mindstorms RIS instead.
    ~luge
  • The difference is purely software- the HW is identical (unless you buy a big package intended for large groups of students, but IIRC that is on the order of a thousand bucks.) And it is, of course, Windows-centric (don't recall if it runs on Mac or not.) If you want Linux, PBforth and legOS are the way to go.
    ~luge
  • I've heard of kids as young as four using the stuff, and I think it is perfectly appropriate in the 7-8 range (my half-siblings will be getting one for Xmas... don't think they read /. so the secret is safe :). You'll certainly have to help out with construction, but the visually oriented programming is pretty easy for kids to get used to.
    ~luge
  • I've read Mobile Robots (very good book!) but have not actually constructed anything in there. The big differences are going to be ease of use and flexibility. If you are handy with a soldering iron, then the Mobile Robots DIY approach shouldn't be too intimidating. (Don't know anything about Linux support on the SW side, though.) It is also far more flexible- the RCX limitations of three inputs and three outputs gets very chafing very quickly. OTOH, if soldering irons sound dangerous to you :) or you want to get results NOW, then RIS is for you.
    ~luge
  • by mattdm ( 1931 )
    It's not worth doing it that way. By the t ime you've purchased the necessary sensors and motors, you're over $200.

    --

  • I had the chance to play with the Lego Mindstorms system earlier this year...the IR port on the RCX has a maximum range of 1.5 meters. This got me thinking...what about programming a team of, say, six Mindstorms to behave as a team? I'd certainly like to see any research someone has done on this....

    The Kulturwehrmacht [onelist.com]
  • Is it possible to connect the controllers in parallel? This could hours of fun all by its self. One for movment one for options.
  • For 'team' robotic efforts, one resource to check out is Robocup [robocup.org], a world-wide robotic soccer competition.

    I don't have any specific references here, but I believe there have been some published papers (as a result of this competition) regarding team coordination and strategies. A good starting search would be the various AI journals.

    Good luck!

  • by The Cheese ( 17421 ) on Wednesday November 24, 1999 @06:35AM (#1506949)
    There are several kits available from The LEGO Company (TLC) which let you build Mindstorms-style robots; the Robotics Invention System (RIS, the Mindstorms 'basic' set) the Robotics Discovery Set (which has the 'Scout' microcomputer instead of the RCX that comes in the RIS; the Scout doesn't require a PC for you to program it) and the Droid Developer Kit (which has yet another 'Scout'-style programmable brick). These are the three robotics kits available from The Lego Company [lego.com].
    Available from Pitsco/DACTA is the RoboLab, a LEGO robotics kit aimed more towards the Educational sector, primarily as a teaching tool for educators looking to teach scientific-minded youths the joys of programming and the wonderment that is robotry. It's available from PITSCO/Dacta [pitsco-legodacta.com]. I've ordered stuff from them online without having to prove if I'm an educator, but YMMV.

    I've had the Unofficial Guide to LEGO Mindstorms for a month now, and my cats are starting to think I like my robots (Clumsy Pike and Hovis) better than them (Hydrox and Pork Chop, so they don't get jealous)(I think they've got FELUX running on my PC).

    I hope that this is of some use to someone looking for the perfect gift for that geek on their Christmas list.

    -The Cheese, who's next plan is to RULE THE WORLD!

    PS; LEGO also sells a wireless IR remote for controlling the RCX.

    PPS; Check out the online resources at LUGNET [lugnet.com].
  • Good point. I'm thinking maybe carry a plug with it that connects it to a recharging station and have the 'bot carry rechargable AA's. I guess I could also have it signal me saying "I'm Hungry" on the LCD.

  • I would have to say it depends on where your interests lie.

    I used Mobile Robots when building a robot for a competition in a 4th year engineering project. It was a two-person team, so I developed a lot of respect for how hard robots are to build.

    I also own a Lego Mindstorms kit.

    I would have to say that Mindstorms provides a much more solid base to build on. You can spend a lot less time getting electronics to work and a lot more fun doing the (IMHO) fun part - programming the behaviour, etc.

    Of course, if your interests are more in the electronics (putting the board together, building your own sensors, etc.) then you might want to go the do-your-own route outlined in Mobile Robots.

  • There's nothing stopping you from lopping off the jack and doing a direct connect from the adapter wires to the battery terminals. Not convenient, and ugly by some standards, but easy as pie.
  • You're confusing a power plug with a power jack. The wall "brick" that you buy from Radio Shack has a plug on it that plugs into the jack on the lego rx. Unfortunately, the new 1.5 version has no jack.
  • Literally about a week ago, the idea of building autonomous hobby robots suddenly struck me as
    a fun idea.
    I picked up a copy of "Robot Science and Technology" magazine and thumbed through it, and
    unfortunately, just about everything seems to only have software support for Windows (other than the
    hobbyist-developed stuff for Mindstorms mentioned here.)
    However, I noticed one other thing - some articles about "Battlebots" and "Robot Wars" and such
    implied to me that most of the robots in such contests aren't autonomous, but are actually
    radio-controlled...
    So...it seems that if one isn't "stuck" on the idea that the processor of an autonomous robot
    "must" be an integral part of the robot, it seems that there's no reason you couldn't build a set of R/C hardware robotics...then write a nice, standard C, C++, Java, etc. etc. program that
    runs from an old Linux box, and controls the robot from an R/C controller plugged into a serial or parallel port, or something of the sort. You'd have to put a transmitter on the robot to send sensor data back, but I imagine (in a purely academic if not outright naive way) that this isn't that big of a problem.

    Plus, then you can take that old Beowulf cluster that's gathering dust in a corner of your apartment and build a supercomputer brain for your bot....

    Which all leads, in a rambling, incoherent sort of way, to my question, which is - are there any good sites for "Hobby robotics with Linux" floating around on the net that anyone can recommend?
  • by Anonymous Coward
    On the whole diy, simple robotics kick, something that might be interesting for people who want a little bit more platform independance and a simpler, but more programming friendly development environment might want to check out something called a Handiboard. I think that it was originally designed at MIT. Unfortunately, I'm too lazy to go search for some good links, but I have seen stuff on the web. My experience with it was building a robot for a competiton. The handiboard controller supports a variety of different motors, has a small LCD panel, and supports a variety of sensor input. Our robots were able to read IR, used a CDS cell to detect changes in operating environment and many other cool features. The cool thing is that the handiboard can be programmed in something called Interactive C. There is even a linux version of this product. It's real C (but with a few limitations) with some special libraries of functions for motor control, IR, etc. Its incredibly easy to code for the robot if one has any experience whatsoever with C. You can mount this board on anything. I used erector set parts for building the robot, but some people used construx, kinex, and even "welded" pvc. Pretty rad stuff. The only drawback is that I'm pretty sure the controller was somewhat pricey though there are places that sell used/refurbished boards.
  • If you haven't seen it earlier, you may want to check out the work of Maja Mataric, whose "nerd herd" of autonomous robots build up a sort of team/cooperative behavior by sending signals to one another; in an experiment, they collectively try to herd six hockey pucks toward two goals in the most efficient way by understanding which members of the herd are closest to the pucks. You can check it out at http://www-robotics.usc.edu/~maja/home.html.
  • The main problem I have with Knex is that it only gives you 90 and 45 degree angles. To do a lot of interesting things (domes, frinstance), you need 60s and 30s at least.

    One thing that would be great is a set of appropriate Lego Knex connector pieces, taking advantage of the strengths of each system. Lego is excellent for building solid-volume pieces of large mass. Knex is much better at building framed structures of low mass. It's easy to build a 6 foot Knex building, and a lot harder with Lego.

    BTW, it is time to make plans for your Knex purchases. Every year, the day after Christmas, large Knex sets to on massive sale at Target. It is a great opportunity to stock up on big volumes of parts. The "hyperspace training tower" is a steal when it can be found for $49, as are the Ball Factory and the Roller Coaster.

    Hint when building knex: sort out parts by color before commencing construction.

    -dB

  • Maybe Energizer and Duracell offered them an incentive :)

  • Will prolly want to pick up the book from Chapters.ca instead of fatbrain, here's the link:


    Click me! [chapters.ca]
  • The real interest in my family (mostly from my father!) would be if this sort of thing is usable with Meccano - Erector to anyone in the US. Not as quick to use as Lego, but you can do far more proper engineering to get some really nice models. If we could use this somehow, it'd be nice...

    Greg
  • The Kiss Institute has an incredible Lego kit, with a handiboard, LOTS of Lego pieces, and some neat sensors eg, rangefinder... Problem is price. I have used this in a course at AAAI this summer, taught, I believ by Dave Miller, and after a few hours we were making a robot which scooped Pingpong balls into the kitbox lid, and holding a tournament. Warmly recommended!
    http://www.kipr.org
  • I knew this sounded familiar!

    GCSE Information Systems, 1995. I had to play with some robotics, and we did this all with Lego running through Control Lab (I think - memory's a little hazy) under MacOS 7. Gave us lights, motors, rotation sensors, temperature sensors, light sensors and push switches. Programmed in something that I remember looking like a weird BASIC derivative. We made a greenhouse with a temperature regulation system - it was the original assignment, we just went thoroughly OTT on it! Others managed some really fun stuff like automated carwashes (well, simulated models... you get the idea!) , so it was a fairly powerful system. Not ideal, by any means - I remember being frustrated that I couldn't interrupt things - but it worked.

    Would this be the same system, by any chance?

    Greg
  • Is there any sort of development environment for the Palm Pilot to control Mindstorms? I suppose OmniRemote [pacificneotek.com] could be used just like the Mindstorms remote, but a complete development environment on the palm would be pretty cool.

  • by The Cheese ( 17421 ) on Wednesday November 24, 1999 @11:08AM (#1506966)
    The Scout has only two inputs and two outputs (compared to the RCX's three apiece) but doesn't require a PC or IR tower (the IR tower is part of the RIS) to be programmed. The RCX requires that you compile your software on your PC or Mac (the RIS only provides cabling for connecting the IR tower to an 8-pin serial or [using the provided adapter] a 25-pin parallel port, but Mac adapter cables are available from PITSCO/Dacta) before downloading it to the RCX. The Scout can be programmed using the on-screen display and menus.

    I would recommend the RIS with the RCX for anyone who wants to get into the guts of the matter, as this will allow you to choose your programming environment, rather than be locked into the built-in environment of the Scout.

    -Cheese, who really does have a real job.
  • The difference is *not* purely software; the Scout has two inputs and two outputs, whereas the RCX has three apiece. Also, the Scout is programmed from onboard, onscreen menus. The RCX is not.

    The Cheese

    Nitrozac Boot Squad
  • 60 degree angle? Connect two purple hubs into a 90 degree corner. Connect two rods into the second slot from the top or the bottom of each. 60 degrees.
  • I think that the Robolab software has been reworked since then, and includes a variant of the Mindstorms software, which is _very_ object-oriented. Mac adapter cables for the RIS's IR tower are available from PITSCO-dacta [pitsco-legodacta.com].

    The Cheese

    Nitrozac Boot Squad
  • by Anonymous Coward
    The O'Reilly book is OK but the pictures really *suck* and it's too choppy, the book to get (saw it at the conference at MIT) is Dave Baum's Definitive Guide To Lego Mindstorm's from APress - great pictures and Dave's the man - created NQC -the only way to go for programming Lego cause it works on a Mac
  • Why was this moderated down? This is acutally a good idea
  • for any questions '/.' readers may have on (Lego) Mindstorms and programming the definitive site to go to is LUGNET . Here's the pointers to the site. It's a true master piece of web engineering and excellent source of information.
    • lugnet [lugnet.com] - Lego Users Group, main page. Links to all the user groups.
      palm [lugnet.com] - palm development for Lego mindstorms
      robotics [lugnet.com] - talk/problem solving about programming, building and designing robots in lego

    a unique feature [lugnet.com] of LUGNET is the three way interaction between newsgroups using news (nntp), email (using smtp) and the web (using http). You can interact/subscribe through LUGNET by any of the above protocols and the discussions are simultaneously readable via news, web or email.
  • Well the SMindstorm (tm) series was actually quite revolutionary until it was found that by actually handling the pieces too long would cause abnormal side-affects, shortning of the genetalia and uncontrollable flatulence.

    Fortunately this was soon discovered and covered up. A new version of the series was released with the shortened title 'Mindstorm'. The only side-affect from this product appears to be a loss of brain cells, which is usually caused by the action of slamming one's head against the wall in frustration of getting one's bot to do things correctly.

    Seriously though, Lego Mindstorm (Invention Sys) is great and definitely worth it. Especially the Add-On pack [Extreme Creatures]. I have had fun pitting my robot against my friend's in the basement. We have them programmed to attack and dismantle any robot they come across.

  • You can get the RoboLab software from a Lego Dacta disributor (find them at http://www.lego.com/dacta [lego.com] You will also need a serial cable to connect to the IR box. (also from Dacta)
  • Yes, you can make a single 60, but you can't easily make a 3-d triangular equilateral polyhedron, with all the angles at all the vertices 60s. Knex makes it easy only to do 90s and 45s at those junctions. -dB
  • it is kinda strange that the review dismisses the other (non NQC) environments as mediocre since they need the new firmware...

    I would say that the fact that pbForth and legOS replace the firmware is the main advantage - the firmware has some serious limitations (32 variables...)

    I would say that the legOS is best environment, it is not very easy to set but it is not very hard either (on linux it is fairly easy).

    the second best is pbForth. while it is true that the forth is not one of the most popular laguages, it is widely used in embedded systems, mainly because it is very efficient and I have heard lot of praise for this language. it takes a different mindset to use it but it definitely has good points...

    I have both of these and I don't even consider nqc, mainly because it uses the LEGO firmware...

    all above is IMO, of course, YMMV, I just wanted to point out that people might see it differently...

    erik
  • pbForth: works on mac too (well, actually pbForth runs on the RCX itself, you only need the serial port and terminal program to communicate with it),

    legOS: I think you should be able to get gcc up and running on mac (and then legOS works too).

    erik

I've noticed several design suggestions in your code.

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