Fun Projects for your LEGO® MINDSTORMS® NXT!
|Important: Use step 3-AA if using AA
batteries, use step 3-Li if using the NXT Lithium rechargeable
3-AA (for AA batteries only)
Continue to Step 4
3-Li (for Lithium Rechargeable Battery Pack only)
|Use two medium length wires to connect the two drive
motors to ports B and C on the NXT.
Important: Keep the left wire on the left and the right wire on the right (do not cross the wires).
Building Tip: Weight Balance
When building a robot with a castor wheel, it is important to consider the weight balance of the robot. For good turning, you want to have most of the robot's weight over the drive wheels, if possible. But there must also be enough weight over the castor to keep the robot stable and avoid tipping over. If too much weight is over the castor, the robot may struggle to turn, might get caught up and stall, or the drive wheels might start slipping. However, if too much weight is over the drive wheels, the robot may pop a wheelie when told to drive backwards.
As determined by the experiment below with a small scale, the Castor Bot robot has a total weight of 624 grams, with 466 grams over the drive wheels. This works out to 75% (466/624) of the weight over the drive wheels.
The Castor Bot is a basic two-motor drive robot with sturdy construction that turns easily. You can use it as a starting point for your own projects, and program it however you want. To get you started, here are a couple of programs that demonstrate the use of the Move block to do different kinds of turns.
The TurnDemo program (Easy) shows three kinds of turns using the Move block:
The Spiral program (Intermediate) demonstrates using the Steering parameter on the Move block's data hub to numerically control the amount of turning. It makes the robot drive in a spiral of steadily decreasing radius.