Activity 4 – Amazing turns

Yes, the quickest route between two points is a straight line, but what is the fun in that?  In the previous section, you had practice in moving forward and backward with different speeds and times.  By now, you should be able to predict how far scribbler will move with different settings.  Now, we are going to change the speed of the Scribblers’ wheels so that one turns faster than the other.  Can you think what will happen when we do that?  If one wheel is moving faster than the other, the Scribbler will turn and make a circle. 

 

In fact, the Scribbler is so smooth we can use it to draw lines and shapes!  Take a look at the Scribbler, there is a hole in the top of the robot.  That hole is for holding a Sharpie marker or a Dry Erase marker for use on a while board. 

 

Pre Activity Check List:

 

  • A scribbler robot with charged Batteries.
  • Scribbler Connected to your computer via USB cable. Note: Review the Getting Started section to see how to properly connect the Scribbler to the computer.
  • Sharpie and a paper/pad OR a dry erase marker white board. NOTE: Do NOT use a sharpie on the white board.
  • An area where you can place the Scribbler to draw.
  • Review the Insert a Move Command Section of the Scribbler Tips Documentation

 

Activity Steps:

 

PART A: Simple Drawing

  1. Open the Scribbler Program Maker on your computer. 
  2. Start by adding a Pause Tile for 5 seconds
  3. Next add a Motion Tile
    1. Set the Motion Tile to move forward on one wheel at a speed of 50 and the other at a speed of -50.

 

    1. Now, we are going to use the Pen to draw on a piece of paper or white board. 
    2. Set up your paper or white board ahead of time.  Only use Sharpie markers on paper, not on a white board.
    3. Send the program to your Scribbler. Place Scribbler on the paper or white board and insert the pen into the Pen Port on the Scribbler and watch what happens!
    4. The Scribbler should have just moved in a full circle for 4 seconds.  When you lift the Scribbler up, you will see a dot or a very small circle.  That shows us that the scribbler can rotate directly on its center, which will be very useful.
  1. Now we can draw a REAL circle on our paper.
    1. Change the program to have a speed of 100 (positive) on the right side and a speed of 10 (positive) on the left side.  Set the time to be 5 seconds.

    1. Copy the program to the Scribbler.  Move it to your drawing surface.  When the program runs, your drawing will look like this (Black Line):

 

    1. Use your ruler to measure the arc. 
    2. What is the diameter of the arc in inches? (Green Line)
    3. What is the radius of the arc in inches? (Red Line)

 

Formulas for determine diameter and radius.

  • Diameter = Length of a straight line through the center of the circle, touching the circle at opposite points
  • Radius = Diameter / 2

 

  1. Now it is time for a little creativity!  Write a program that will make a full circle. We were able to make a ½ circle using 5 seconds as our time.  So, using our calculations, we would be able to double the time to 10 seconds to make a full circle.  One problem though; the Scribbler Program Maker only lets us use a maximum of 5 seconds for the move time.  Is there another way to get the robot to go for more than 5 seconds?  Go ahead and try it out.

 

In programming, there is usually more than one (sometimes several) ways to accomplish the same tasks.  In this case, we had to figure out how to make the robot keep moving after 5 seconds to complete our circle.  Here are a couple of ways you could have done it:

·        You could have used the copy function and copied the first Motion Tile and pasted it right after the first one.  When the program is run, the Scribbler will run the first Tile then the second Tile.  Effectively running for 10 seconds and completing the circle.

·        You could have also reduced the first Tile to be 2.5 seconds rather than 5 seconds (to make it a quarter circle) and copy and pasted it 4 times (4 quarters equals 1 whole circle!)  Why do that if there is more work in the copy and pasting?  Well, you would then be able to ‘fine-tune’ how long the Scribbler goes in the circle.  Since you can never go more than 5 seconds, you would not be able to adjust the time upward with the first method.  However, you could move one of the 2.5 seconds Tiles to 2.7 to make sure it is exactly where you want the Scribbler to stop.

·        When we get a little further along, we will learn about programming with sub-routines and loops, which will be other ways to tackle these issues.

 

Mini Activities

 

·        Adjust the speed of the Motion Tile to make an 4 Inch diameter circle.  Record in your log:

a.    Left Speed

b.    Right Speed

c.     Total Time (If you use multiple Tiles, add up the times in each)

 

·        Create a program that will draw a 5” straight line, spin 90 degrees in place to the right and then draw another 5” straight line.  The result should be two straight lines joined at a sharp right angle turn. Record in your log:

a.    Block 1:

·        Left Speed

·        Right Speed

·        Total Time

b.    Block 2

·        Left Speed

·        Right Speed

·        Total Time

 

Practice the above activities until you have a good feel for how to judge the size of the circles Scribbler will make.

 

Running a Maze!

 

Now that you have mastered both straight lines and turns, let’s put your knowledge to work.  Time for some Amazing Turns!

 

Your Instructor will show you a maze that you must navigate with your Scribbler. 

 

Program your robot to complete the maze.  You will be using the pen/marker to trace your path in the maze.  You are not allowed to go outside of the boundaries of the maze.  You must complete the entire maze to finish.  This may take multiple trials. 

 

Helpful Hint: It helps to know the measurements of each section of the maze.

 

Here is what a sample of the maze looks like:

 

 

 

>>Update the Lesson Worksheet with your observations.