I. Building a mobile robot using Lego kits.

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  1. The Lego body.

  2. One of the goals in this course is for students to gain experience in robot building. When designing a mobile robot, there are some questions that should be asked:
     
      The design of the robot's body can become something close to an art, which can be approached best through experimentation. Lego blocks are an inexpensive way that provides the freedom to build a body over and over again. Students can discover what particular configuration works best from them, and it is relatively easy to modify the robot for new tasks.
    There are several tricks that can be used when designing a Lego robot. The art of Lego Design, by Fred Martin provides a first glance to Lego building covering topics as gear chains, structural integrity, and free wheels.

    For our course, the preferred way of locomotion is by using wheels, given that our test arena is flat and the step parts are easy to climb. Students should decide how to power the wheels, and how to make the robot steer. These are some of the wheel configurations that have been successfully used in this course:

    Two independent power wheels. This arrangement provides for a robot that is easy to steer, and that can do very sharp turns. Problems appear when you want this robot to move in a straight line!

    One power wheel with power steering. This is the tricycle arrange, in which the front wheel both moves and steers the robot. This requires a little of ingenuity with the steering gears.

    Tracks. This is a variation on the independent power wheels. It provides extra traction and sometimes makes easier for the robot to move straight.
     
     

  3. The Handy Board.

  4. The Handy Board is a microcontroller based on the Motorola 68HC11 microprocessor. The Handy Board includes a 32K RAM, output ports for four motors, 16 input ports for sensors and a 16x2 character LCD screen. Additional information can be found in the Handy Board home page.
    Some of the parts of the Handy Board are shown in the picture.
    Handy Board Diagram
    For a more detailed description of the Handy board, see the Handy Board Manual on the docs section of the Handy Board page.
     
     
  5. Sensors.

  6. If you aspire to build a more or less intelligent robot, you need to be able to obtain data about the environment. There are a variety of sensors that can be used for this purpose. Sensors can be classified in two categories: digital sensors and analog sensors. Digital sensors return discrete values (typically 0 or 1), while analog sensors return continuous values. One thing to remember about analog sensors is that they are not 100% accurate, so you should be ready to compensate for that in a program that interprets sensor readings. Let's describe the sensors available for our Lego robot in the lab:
     
  7. Interesting stuff

  8. Here are some pages related to Lego robots and robots in general.
    Here are the pages of the students from this course.
     
  9. Where to get the Lego kits.

  10. Following is a list of sites where Lego blocks and the Microcontroller can be obtained: