Page 46 - The Unofficial Guide to Lego Mindstorms Robots

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train motor
LEGO sells an entire line of train sets. The train motor can be controlled by your RCX; as a matter of fact, you can make an
"intelligent" train by mounting the RCX in one of the cars.

For a Rainy Day

To see exactly how efficient the geared motors are, try this experiment. Use one of the
"wire bricks" to attach two motor s to each other. When you turn the shaft of one motor,
t he other motor's shaft will turn simultaneously. What's going on here? Just as you can
supply power to make the motor turn, turning the motor with your hand generates power.
This power is transferred to the other motor, where it's converted back to the movement
of the shaft.

Of course, you haven't actually built anything useful. But it's a good demonstration of the
efficiency of these motors. The shaft on the second motor turns at nearly the same speed as
the first motor, which me ans very little energy is lost in converting mechanical energy to
el ectrical energy and vice versa.

If you have a choice of motors, you'll probably always use a geared motor. It is more efficient, more convenient, and less bulky
than the standard motor. The micro motor is hard to find and not strong enough for most tasks.

How can you get more motors? RIS comes with two motors, but there are three outputs on the RCX. You can get another
motor in the RoboSports expansion set, but it'll cost you $50.

You can order extra motors from the LEGO Shop-at-Home service, one of The LEGO Group's best-kept secrets. This service
is available in the United States at (800) 835-4386. They have a variety of sets and spare parts—the item numbers for the
motors are as follows:

• Standard motor, item 5114

• Micro motor, item 5119

• Geared motor, item 5225

• Train motor, item 5300

You can also order the first three motors from Pitsco LEGO DACTA: (800) 362-4308.

For more information on extra parts and ordering, see Appendix A.