Robotics Lab #0

Introduction to the Robotics Lab

810:159, Robotics Laboratory

Fall Semester 2006

Due: Monday, August 28th, 2:00 PM

In the lab I used a set of PowerPoint slides.

Administrivia (all that stuff I shouldn't have to do, but which takes up too much time)

• Please make sure that you are familiar with the syllabus for the RoboLab.  Most of this is common sense stuff, but I put a lot of time and thought into writing it, so, please put some time into reading it.  In particular, please read the information about RoboLab course policies regarding attendance, equipment access, academic misconduct, and a how I suggest/expect that you structure your teams.

• As was noted when you read the syllabus, each student will be issued two keys for access to the RoboLab.  If you were not in class today, you will need to talk to me so that I can get enough information to have these keys issued to you.

• Form up into groups and get an initial assignment of your locker and computer.

Learning about the basic parts

• Take a little bit of time to familiarize yourself with the basic robotics equipment.  In particular, pull out the parts inventory list (in the green bin).  This will be helpful in learning the names of parts.  ("Half of the knowledge about something is knowing what to call it"  Don Weiner, MIT).
  • The parts in the red storage unit tend to be standard LEGO/TECHNIC (C) parts.  If you grew up with these like I did, then you probably know most of these. 
  • Notice the "brick separator" in Slot 1 of Tray 1.  Once you figure out how to use this it comes in very handy and saves a lot of wear and tear on parts.  Please get in the habit of using this rather than using a pocket knife, your teeth, or whatever "backwards" technique you may have grown up with.  I am very anal about treating pieces with "respect."  Don't let me catch you abusing pieces.
  • Check out the axels in Tray 2.  Notice that these are named by their length with respect to standard bricks.  Thus, a 4 stud axle will be exactly the same length as a brick that is 4 studs long.  As you use the plans in the Constructopedia (green bin) you will always see a number next to an axle referring to its length.  You can compare it to a brick or use the guide on the back page of the constructopedia to determine which axel you need (of course if you play with these enough you start to just "know" which size each axel is.
  • Check out the parts in the green bin.  In particular, the loose parts and the parts in Bag 1.  These include the RCX brick, the motors, and the sensors.

   

• So now let's take a little bit and see how these things all come together.
• Pick up the RCX brick.  This is the large yellow block that serves as the brain of your robot.  Install six of your batteries in the robot and press the red On-Off button to make sure that everything is working properly.
• Locate two of the motors and two of the short wires from Bag 1.
• The black squares labeled A, B, and C on the RCX brick are motor ports.  Attach one end of each wire to a motor, then attach the other ends to motor ports A and C.  As you experiment with the robots you will notice that the orientation of the connecting wires makes a big difference.  I have never completely figured out the "proper" way to connect these, and LEGO changes their mind from example to example.  What I have started doing, however, is trying to connect the wires away from the A, B, C, labels (to me this is "parallel" to the RCX brick) and the other connection  "perpendicular" to the drive shaft of the motor.  You can turn either of these connections by 180 degrees and you will reverse the power to the motor, thus reversing its direction.  If you turn either connection by 90 degrees, you get similar results, although I haven't ever taken the time to figure out how they are related.
• For this initial testing, there are several simple programs loaded onto your RCX.  The right side of the display window shows the active program number.  If program 1 is not the current active program, push the gray Prgm button to select program 1.
• Now, press the green Run button to start program 1.  The RCX should beep and turn on both motors.  Press Run a second time to stop the program.
• Now, find two touch sensors and two short wires.
• The gray squares labeled 1, 2, and 3 on the RCX brick are sensor ports.  First, attach one end of each wire to a touch sensor.  Then, attach the other ends to ports 1 and 3.
• Using the program button, select program 2.
• Press the green Run button to start program 2.  The motors should now be on.  Press the yellow touch sensor buttons and observe what happens.  When you are ready, press the run button a second time to stop the program.
• Remove the touch sensors from the RCX but keep the motors attached..
• Locate a light sensor and the test pad.
• Attach the light sensor to port 2.
• Place the RCX on the test pad, and position the light sensor near the black line.
• Select and run program 3.
• The motors should be on.  Observe what happens as you move the light sensor onto and off of the black line.

Your first assignment

• So now it is time for you to do a little bit on your own. 
• Prior to the next time we meet your group needs to construct a variant of the "RoverBot"  The instructions for this can be found on pages 10 through 35 of the constructopedia.  To receive credit for completing this lab you must
  • construct the Driving Base,
  • a design to make the robot mobile (Three separate sets of instructions are given in the book - for the wheel sets, the legs, or the tracks.  I will assign each team one of these three sets so that we can compare them as a group),
  • the double bumper,
  • the light sensor. 

  Notice that there are more directions in the book then you will actually follow because there are three separate sets of directions for making the robot mobile.  You may choose which of the three directions you follow, or you may explore and create your own design.  You also may "decorate" your RoverBot in any manner you see fit, although there are no requirements to do so.

Deliverables

Your deliverable this week is a completed, mobile robot that responds properly to program 1 that we used in Part 1 of this lab.  You should also have a separate double bumper set, and a separate light sensor set.  Since you have not completed any programming this week, you may ignore the normal  homework collection policies.