Institute for Personal Robots in Education Blog

LEGO Mindstorms NXT: First Impressions

Speaking of Personal Robots, LEGO made a definite first splash in this area several years ago when it released its LEGO RCX as the Mindstorms Invention System. Designed for ages 10 and up, the RCX was probably an ideal toy for a kid. Other than the RCX brick itself, most other parts (sensors, motors) were standard LEGO pieces that one even had in their own other LEGO kits. The genius of RCX was that it integrated well with existing LEGO pieces and more or less looked the same as any other LEGO piece. The same wire connectors worked for connecting sensors and motors to the RCX. A graphical 'programming language' was used to design control programs. Several computer science departments turned to RCX (probably the best reverse engineered commercial electronic artifact of its times) and designed several innovative courses, labs, and programming languages (from C, NQC, LISP, JAVA, and even ADA!).

So I just received the Mindsotrms NXT kit from LEGO. This, next generation LEGO kit is a definite move away from the RCX model. The brick controller itself is not too different from the RCX: about the same size, bigger LCD display, three motor ports, four sensor ports (one more than the RCX), a built-in bluetooth recevier (to replace the IR module) and a more up-to-date USB port. The brick itself seems to have better places to anchor other LEGO connectors to build a robot body. The connectors for motors and sesnors have deviated away from LEGO connectors to phone-style jacks and cables. This of course means that you are out of luck with using your old sensors and motors.

For $250.00 the kit inlcudes the following:

  • the NXT brick,
  • a sonar sensor,
  • a sound sensor,
  • a touch sensor,
  • an IR sensor that can sense color as well as proximity,
  • three servo motors (yes servo, so they offer precise control)

Each sensor is approx 0.75inch x 0.75inch x 1.75inch in dimensions, with the exception of sonar which is bigger and has a T-shape for 2 sonar mounts.

The box also comes with an assortment of LEGO pieces that resemble a collection from one of custom LEGO kits as opposed to the generic LEGOs. There are the standard pieces...connectors of various kinds, and there are also oddly shaped ones (elbows, bent beams, etc.) mostly in gray, black, or white color schemes with some orange accents.

The box comes with a booklet that has instructions for building a basic mobile robot which can then be used for adding onto for other projects included on the CD. The box claims you can get started with a robot in 5 min...yeah right. Takes longer to install the Mindstorms software itself!

All claims aside, I was able to easily build the base and then after installing the software and getting into Robolab, I started building the first project, Tribot: it has grippers in front that can be opened and closed (custom parts) to grip and lift a colored ball. The robot can sense the presence of a ball (sonar), move to it, stop when it gets there (touch sensor). Then when you clap with your hands, the sound sensor enables a sequence to close the gripper and then move the robot back. This took me at least 2 hours and I am not a LEGO novice...much time was spent fishing for the right pieces demanded in the construction manual...did I say there are several tiny, custom peices here?

Programming the sequence was easy...but there are bugs in the version shipped. Overall a good experience putting together various control components into a program.

In the end I had a robot that got to the ball, closed (more like slapped!) its grippers on it...and the ball always bounced right out of the claws!

An afternoon's labor...

So, what do I think? I felt like I was in the New Yankee Workshop (the PBS show with Norm Abram the master craftsman who has a special tool for every little job!).

Like the RCX, I think it'll be a good toy for kids.

This is supposed to be an open-source platform so there are (or will be) other development environments. I also saw that there is (or going to be) a Microsoft Robotics Studio interface for the NXT brick. My thoughts on those when I get to play with them...

$250 for the kit is a very

Tue, 2008-09-16 03:33
Anonymous (not verified)

$250 for the kit is a very low price compared to the prices in my country.

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NXT application: First Lego League & Middle School Classroom

Sun, 2008-10-19 20:29
Lego Frodo (not verified)

I read your review with interest Deepak.

I teach middle school in the U.S. and have an afterschool team involved in the First Lego League (FLL) the Fall of 2007. It uses the Lego Mindstorm NXT robot as the straw to stir the competitive drink. Go to for more on that.

I was impressed with the durability and realibility of the hardware (brick and, of course, Legos). I am a litle above a novice programmer. I programmed BASIC back when personal computers were first coming into use. Now, everything has gone visual! I also like the programming language's accessibility (icon driven with choses provided for each icon in s seperate window) for middle schoolers.

The tutorials available in the booklet you mentioned are complemented by those on the software itself. It allows for a gradual building of sophistication for the novice programmer (which is what I work with). We used 2 robots with about 12 kids and frankly they wanted more.

I decided I wanted bite off something bigger. I wanted 15 robots in computer lab-based classroom and after a publicity blitz with my FLL kids doing show and tell-- This Fall I have what I dreamed about! Before I asked for it though, I did some internet research and came across Carnegie Mellon's Mobile Robotics Tutorial Software. You can demo the software, the worksheets, quizzes, etc.

From my season of work with the robots, I sensed it work well in my 6 week, 1-hour clssroom setting. Now, I have 25-30 students coming each 6 weeks and they work in pairs. Students are walking carefully through the connection between concepts like:
Rotation Sensors
The relationship of circumference to distance traveled
3 ways to make the robot turn
Sound sensors, Light sensors and, eventually, touch sensors

The learning materials are carefully crafted from the basic to the more challenging for my 7th graders (12-13 years old). I am using Volume 1 and hope to gradute some onto "Mobile Robotics, Vol. 2". I don't know much about the "C" language , but enough to know I might be the bridge to students onto the same programming in a more sophisticated (more commercially used)language. Having 14 years programming in "C" is my next dream.

Are culminating event this 6 weeks is going to be the 2008 Robotic Olympics.
Open cermonies (robots draw rings),
Events Sumobots, Monster Track Races, Tigerbots (will take a swing at that red ball).
Closing ceremonies (Syncronized robot dancing. It won't be that sophisticated but I think everyone will enjoy)

Can't wait for the event and will try to You Tube if it works. Watch for North Marshall Middle & ROBOTS. Maybe by Spring 09.

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Wed, 2008-10-29 01:24
siddhc (not verified)

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I was able to easily build

Wed, 2009-03-11 05:33

I was able to easily build the base and then after installing the software and getting into Robolab.
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Can a 9 1/2 - 10 year old

Tue, 2009-03-24 12:38
Can a 9 1/2 - 10 year old REALLY do this on their own?

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Wed, 2009-04-08 16:30
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