Mindstorms NXT robot Review

Discussion in 'Reviews and Articles' started by tweakmonkey, Sep 3, 2006.

  1. tweakmonkey

    tweakmonkey Webmaster Staff Member

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    [SIZE=+2] Lego Mindstorms NXT
    [/SIZE]​

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    Available: Now. Easy to find online, hard in stores except Lego stores (I hear). Released in August 2006 I believe.
    Price: about $250
    Requires: 6 x AA batteries (sold seperately), USB or Bluetooth connectivity (PC/Mac)
    Official Site: LEGO Store - LEGO® MINDSTORMS® NXT
    It's a 2nd generation (AFAIK) build and program your own robot kit from lego
    Features / Specifications
    • All-new NXT Intelligent Brick with 32-bit microprocessor, more memory and FLASH
    • 3 Interactive Servo motors feature built-in rotation sensors to align speed for precise control
    • New sound sensor reacts to sound commands, patterns and tones
    • New ultrasonic visual sensor responds to movement
    • Improved touch sensor reacts to touch and release
    • Improved light sensor detects different colors and light intensities
    • 519 specially selected LEGO TECHNIC elements for sturdy and durable building and improved functionality and movement
    • 4 input ports, 3 output ports and 7 6-wire cords
    • Matrix display
    • Real sound speaker
    • USB 2.0 and Bluetooth support
    • Easy-to-use PC and Mac compatible interface
    • Intuitive, icon-based drag-and-drop program "building" environment
    Pictures

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    The inside cover of the box, showing the contents. Mine was slightly beat up when it arrived, but overall it came in decent shape.


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    The cat's been very curious the last few days. She's not really scared of it, but very interested.

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    Here's all the stuff unpacked with my first robot in the background.

    There are lots of little parts and at first it's a little bit intimidating putting them together. I read the manual (~70 pages) so I understood what all the sensors and things do. There's a "get started" pack that lets you begin building your first bot right away. You'll need 6 AA batteries to power the bot. I found an 8-pack of Energizer 2500mAh batteries that charge in 15 minutes at Best Buy for about $25. So far I haven't had to charge the batteries yet.

    There are four sensors (light, distance, sound, and touch) and three motors. On the NXT box (the brains of the unit, where USB/bluetooth and all the sensors/motors connect) you can write programs directly. Or if you prefer you can use the Windows/Mac software to program in a GUI environment that's very easy to use. Also built into the NXT unit is a sensor test and demo (which is used for the first basic robot).

    You hook up the four sensors to the bottom of the unit with what looks like a phone cable. All the cables are interchangeable and there are enough to use everything the kit includes simultaneously. The sensor test takes only a few minutes and is very interesting. The first port connects the touch sensor. When it's connected and the test is run, a Lego head says "Whoops!" when you touch the sensor and the screen indicates a binary value of "1" has been assigned because the sensor is activated. When it's released the number goes back to "0".

    The second sensor connects the microphone which can sense the difference between human and non-human sounds (to a point) by measuring the decibals differently for a person. The value is indicated on the screen, from 0 to 100, 100 being the loudest. The third port uses the light sensor (which so far for me hasn't seemed too accurate in determining color). It also has an output light to measure reflective properties of a surface. The sensor can detect direct and ambient light accurately. Finally, the fourth sensor is the Supersonic sensor, which functions like a bad's radar. This is the unit that looks like the eyes of the robot (similar to Johnny 5's Head). It bounces two soundwaves across the room and takes the reflection to determine how far it is from an object. It's very accurate! I tested it within 1cm accurately. It could also be used to determine how fast an object was moving with some clever programming.

    The first bot took me about an hour to build, screwing around and getting an idea of how it all worked together.
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    It doesn't do much at this stage, mostly drives around and makes basic turns. Then it was time for upgrades...

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    Here's the bot flipped over, so you can see its rear wheel is just a standard spinning disc made from basic Technic pieces. The front wheels do well on carpet and the three motors have ample power. The phone cables that power the motors can be seen here.

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    Johnny 5's head, the supersonic sensor that resembles a bat's radar system.

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    The NXT control brick. At the top you'll see the ports A, B, C, which control the motors. They all function the same, but to keep things standard, you'll usually use B and C for primary movement and A for other features. At least that's how it's been so far with the TriBot and arm. You can change which motor is controlled by which port by telling the program what motor to turn at what time, etc.

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    This is the back of the light sensor. Here you can see the female end of the phone cord style connector.

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    This is the assembled and completed Tri-Bot. Including the other steps, it took me about an hour and a half on my first attempt to work out all the bugs. From the last image, you'll notice it now has claws in front. These are controlled by the third motor. It rotates a pair of gears underneath forward or back, which controls opening and closing of the claws. The white sensor aiming directly at the floor (at the base of the arms) is the light sensor. It's used to determine what color the surface is underneath it. On the test pad there is a black circle and the bot is programmed to stop when it sees black, so it doesn't leave the pad.

    The sound sensor is mounted up top behind the NXT brick. Its purpose is to gather sounds for commands. In the first program where you use it, the bot waits for your command (any word at 50%+ volume to the microphone) before grabbing the ball.. The supersonic sensor in front (that looks like its head) is used to determine how far away the object is. Your first program with it will require you to set the ball with 15 inches I believe, at which time the robot charges forward and waits for your voice to grab the ball. It can be pretty scary when the bot drives forward! If it misses the ball, it won't stop until it crashes its sensor into something. Hanging directly down from the head is a bar that swivels when it runs into something. As it swivels downward, it makes contact with the touch sensor, which informs the NXT box that the sensor has been triggered.

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    Here's the tri-bot ready to charge for its ball.

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    The back of the Tri-Bot. You can see how the NXT brick connects to the various components and get a good glimse of the rear wheel. Notice how the cables are rather bulky and look like they'd get in the way -- they don't. The bot can typically be built to allow freedom of motion regardless of the cable length.

    The Tri-Bot is really cool but it has one major downside, at least for me. The whole front area: the head, claws, touch sensor and light are held on by two very short vertical pegs, directly in front of the NXT brick. Since they're so short, they separated when the bot made a fast movement like grabbing the ball. Slowing down the motor's speed would probably help (which is very easy in software), but the default values caused my Tri-Bot to break here often.

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    The second bot, about 1/2 way through the build. It's eventually going to be a crane that moves an arm, then lowers and closes the arm from what I gather. Currently it simply moves back and forth, up and down. You may notice the black cranks next to the front motors. These are very fun to watch as the motor spins to life. Also you can manually move the crane using these.

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    Top view of the crane so far. You can read "First Program / Run" from the NXT brick. It has a simple operating system for choosing what files and sounds to play, as well as full programmability. I hate one thing about it, though. The orange button sticks often. If you don't push it perfectly, since it's rubber and flexible, it gets hung up on the plastic casing. Take a careful look at the black gears. These things fit together like magic. As you reach this stage of the assembly, it's hard not to admire Lego engineers for their job well done.

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    The side view of the crane. Everything from the front part, wrapping around toward the back is currently not functional and only holds the crane off the ground. The somewhat complicated structure of the crane is visible here.

    To Come Later
    I am still working on getting the videos online. I'll post screenshots of the programming interface as well. Also I've barely scratched the surface with this bot, so expect lots of crazy bots before I'm tired of it. :)

    Eventually I'll post recommendations on how to organize the kit if you should buy it, because it's not very fun digging around in a bin for pieces this intricate.

    My Thoughts
    I firmly believe that this is going to be THE toy to have this year. It is well worth the money for a strictly educational sense. This makes learning about robotics, engineering, and programming very fun. I've had a blast with it so far and I imagine some of my creations will be much more interesting. There are bot that walk, one that rolls on a single wheel (like a unicycle) using the light to balance, a cuckoo-clock, nd many more interesting projects out there.

    If $225-$290 is up your alley for a neat toy that will likely bring hundreds of hours of entertainment, this is a very solid BUY recommendation. Now if only I could teach it to handle a laser gun...

    Links
    NXT Repository
    Mindstorms Revolution
    Wikipedia Entry
    Ars Technica Review (10 / 10)
    --------------------------------------------------------

    I got it for $224 shipped which is about $70 less than Lego wanted.
  2. Mr. Ali

    Mr. Ali Junior Member

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    id love to play around with something like this. i just dont have the time with work + school now :(

    have fun, im sure you will.
  3. braaains

    braaains gubble gubble

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    I was looking at those... But i dont know if theyre worth it. Plus i dont program.
  4. funkgab

    funkgab Junior Member

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    looks fun.. gimmie some pics on something on features,etc :D
    too bad i cant afford something like that..
  5. mistawiskas

    mistawiskas kik n a and takin names

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    Johnny5....alive?
  6. tweakmonkey

    tweakmonkey Webmaster Staff Member

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    bump, added tons of info and pictures
  7. chapel

    chapel Jolly Bolly Fo-Folly Staff Member

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    Thats a sweet toy man. Great write up, lots of info, and gives a feel for what its about.
  8. randomtask

    randomtask Chimp.

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    nice insight into the product, cool stuff man
  9. mistawiskas

    mistawiskas kik n a and takin names

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    I really dig stuff like that. I love assembling things and this toy (?) is one cool thing that I may end up needing Thanx for taking the time to review and share this item.
  10. pk_volt

    pk_volt Junior Member

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    what programming languages does this microprocessor support?
  11. tweakmonkey

    tweakmonkey Webmaster Staff Member

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    You can use the internal drag-n-drop GUI programming interface, which does pretty damn good and is supposedly like Lab-View, only easier. Or you can find various ways to run C / C# (I think) programming.

    There's an open source SDK and BlueTooth developer kit, plus a ton of fan sites on hacking and programming them. I'll update the links list in the post.

    The microprocessor is an 32-bit ARM7 that runs at 48 MHz. I believe ARM7's the same architecture as the Game Boy Advance, DS, and iPod, but I'm new it - maybe someone can confirm this.
  12. nomacs

    nomacs oscar mayer wiener

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    i've been thinking about buying these since they came out, just haven't gotten around to it. I used to play with erector sets and capsella (sp?) when i was in like middle school. then i learned how to program, so this would be a cool mix.

    and in any event, robots are teh shit
  13. braaains

    braaains gubble gubble

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    Sweet toy man:


    [​IMG]


    And is that a whistling nerf dart behind the speaker!? Those things worked shitty.
  14. tweakmonkey

    tweakmonkey Webmaster Staff Member

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    Good eye! Yes, they suck.
  15. hans5849

    hans5849 Serious as a heart attack

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    i miss my capsella sets
  16. James K

    James K Administrator Staff Member

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    My kitty!
  17. chapel

    chapel Jolly Bolly Fo-Folly Staff Member

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    Cute kitty.

    I would get a robot like this, but Id probably lose all the parts.
  18. nomacs

    nomacs oscar mayer wiener

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    thats what happened to my lego castle set. :(
  19. pk_volt

    pk_volt Junior Member

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    I need to program one of them robots to be my bitch.


    Now, I"m wondering if vision sensing is possible
  20. Axl_Rose

    Axl_Rose Junior Member

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    Thats pretty sweet. I can't wait to see what kinda things people think of to do with it.
  21. ahhhhh

    ahhhhh Guest

    need help with programmin

    hey guyz..

    I just started programming with this...and am already a lit confused...

    Im doin a project and I need help with codes... I just need to write some test codes for sensors,,,(touch, light, and compass calib.)

    if any one of you could help..that would be great..

    princess_s@hotmail.com

    thanks
  22. Picotech

    Picotech New Member

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    HAhaha

    I looked early and that is what my mom got me for Xmas we should chat about making something that flies like a dragonfly.:wasted: I am Picotech...