) II computers. Sadly, both mechanical construction sets and computers that kids can program have all but disappeared. But now LEGO Mindstorms offers a worthy, if expensive, replacement.
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LEGO Mindstorms NXT ($250) is a significant improvement on the original 1998 Mindstorms Robotics Invention System, and like its predecessor is a collaboration between the Danish toymaker and the MIT Media Lab. A more powerful computer brain lets the new robots run longer, more complex programs that incorporate inputs from up to four sensors. And using the rods and beams of LEGO Technic construction kits instead of the LEGO bricks of the original makes for more interesting designs. You hook the small, programmable computer, the NXT controller, up to sensors that can detect light, sound, touch, and, through ultrasound, the presence of nearby objects. The NXT uses those sensors to control up to three servo motors, whose output shafts can rotate in precise 45-degree increments.
Sounds simple enough. But building robots requires manual dexterity and patience, a trait few children possess in abundance. Creating the suggested first project, a robotic vehicle that demonstrates all of the sensors, took me a good deal longer than the promised 30 minutes, even after I had sorted the myriad fiddly bits into plastic containers. LEGO recommends the kit for children as young as eight, but I suspect those younger than 12 will require a fair amount of adult help in assembling the models.WHILE YOUNGER CHILDREN may find the actual construction somewhat frustrating, I imagine people of all ages will be fascinated by programming and running the robots. Though the instructions can be entered on the NXT box, it's clumsy -- the screen is small and dim and has no mouse or keyboard -- and not really suitable for anything but very simple maneuvers. Nearly everyone will choose, instead, to install accompanying software on a PC or a Mac. You can then create programs and download them to the NXT using a USB cable (which LEGO supplies) or Bluetooth wireless.
Once you have built your robot, you write programs by arranging icons on a computer display. To create motion you select a motor-control symbol and choose the settings: which motor or motors should turn on, if they should run forward or backward, and for how long. To get the sensors on the robot working, you drag in the appropriate sensor icon, then set the sensitivity level and the action to be taken when it is triggered. With two motion icons and one touch-sensor icon, for example, you could program a robot to move forward until it hits something, then move backward for five seconds. Of course, more complex behaviors can be created, and much of the fun comes with tweaking the programs just to see what happens.
With the original Robotics Invention System, LEGO was surprised when many early users turned out to be adults, especially engineers buying kits for themselves. This time they're prepared, offering advanced programmers a software development kit for more sophisticated work.
I don't know if Mindstorms NXT can provide a badly needed boost to American students' flagging interest in computer science, but there is an effort to make that happen. Carnegie Mellon University's Robotics Academy provides Mindstorms-based curriculum resources to middle schools and high schools and sponsors robotic competitions. There's no proof that giving kids hands-on experience in building and programming contributes to interest in engineering and science, but I can't help but believe it does. Today's leading high-tech toys are video games, which mostly give children vicarious training in handling automatic weapons. LEGO Mindstorms NXT could be a helpful antidote.For past columns and online-only reviews, go to Technology & You at businessweek.com/go/techmaven/ By Stephen H. Wildstrom