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Ev3 Robotics Lesson for Superstars: #2 – Turning

Ev3 Robotics Lesson for Superstars: #2 – Turning
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ev3 robotics lesson

Just like any other lesson, once students have mastered the basic form it is time to add complication. This Ev3 Robotics Lesson is designed to pick up where the last one left off. If you haven’t  checked out Lesson 1, you should do so before starting this one. Go ahead, we’ll wait. Great, glad you’re back! Here we expand on the basics of moving forward, and backwards given distances, and add the turning complication. To begin with we will be turning 90 degrees in either direction with the Lava Challenge. Once we have mastered the 90 degree turn we can move on to turns of different angles. We are also continuing our exploration of the big ideas that computers execute commands in a sequence, and that computers are precise. Additionally, we are introducing annotation, and discussing how to grade the computer programs written by our students.

New Concepts

In this Ev3 Robotics Lesson, the programs students are responsible for become significantly more complex. Unlike in Lesson 1, students begin to see that there is a logical flow to a computer program. They begin to understand that computer programs execute in a particular sequence, and as programs become more complex they are harder to trouble shoot. With this in mind we need to teach a  few new concepts, and adjust our grading. I haven’t touched on grading yet because programs thus far haven’t really been complex enough for robust grading. Now it needs to be addressed, as do the concepts of annotation, and efficiency.

Grading

How does one fairly grade a computer program? Each teacher is certainly entitled to their own opinion, but for me there are three factors that are gradable. Below you will find an assessment rubric I use in my classroom, but first a general discussion. The three gradable factors are:

Functionality

The program needs to meet the criteria of the assignment and work predictably. For a teacher, the most important concept to wrap your head around here is that there are levels of working. It isn’t binary (see what I did there). Instead, when you are designing your own rubric, break the assignment down into parts. If a student has mastered some of those parts, but not others grade accordingly.

Annotation

Annotation in this case refers to computer programs containing commentary within the program that describe various features of the program. In the real world more than one person or group will work on a program over the course of its life. As such, it is important to have descriptions of what each structure inside of a program is actually doing. This is one of those things that is less important within the programs our students are writing, but that we should develop in them as a habit of quality work. Ev3 does this pretty well. If you don’t know how to do it, check out this video.

Efficiency

In the real world this used to be a much bigger deal than it is today, but its still important. Real computer programs should use as few computing resources as possible while still functioning correctly. In the case of an Ev3 program this concept is translated into using the fewest blocks possible to accomplish a given goal. Oftentimes students will want to use additional commands in order to do less precise measurements. This should be discouraged. Remember that one of our Big Ideas is that computers/robots are precise. Make your students be as efficient as possible with their design solutions.

 

Ev3 Robotics Lesson Lava Challenge (90 Degree Turn)

Additional Materials
  • Masking Tape
  • Measuring Tape/Ruler
Board Set Up

You need to create 2 squares made of masking tape on your testing surface as shown below:

img_1741

Depending on the level of challenge you want to provide for your students you can change the size of the tape squares. The greater the difference in sizes the easier the challenge will be.

Challenge

Students will create a program for their robot using the move tank block that allows it to navigate around the inner square while staying within the outer square. Both the inside of the inner square, and the outside of the outer square are Lava. If the robot drives in the Lava it is destroyed. Students need to use the tape measure/ruler to determine how many rotations are needed for their move forward blocks.

Differentiation

This challenge is likely to be incredibly frustrating for your students. This will be the first time they are putting more than two commands together, and figuring out turning can be challenging. There are however, some ways to can alter the difficulty of this challenge to make it easier.

The first way to really scaffold this Ev3 Robotics Lesson is to create the program yourself, but set the number of rotations to “0” on each block. Doing so allows students some challenge in fixing the rotations, but gives them a baseline of what to do. In my classroom I project my program on my Promethean Board for a 1 or 2 days until my students get the hang of what they should be doing. This challenge will take up to five days for them to complete. Once the majority appear to have the hang of it I stop posting it.

You can also have students use the motors themselves to figure out the speed/direction settings in the move tank block. To do so, simply plug the robot in to the laptop and selecting the port view feature in the Ev3 software. You can find the port view feature near the download icon. Next you just need to set the motors to readout to rotations, and zero them out. Finally you simply turn the wheels manually, and record the numbers you see when you get the turn correct.

You can also make this challenge easier or harder by where you place the robot to begin as well as which direction the robot faces. It is significantly easier to complete this challenge if the robot begins by facing a direction parallel to one of the sides of the middle square. Finaly, I add difficulty to this Ev3 Robotics Lesson by making students program the robot so it stops exactly where it started.

Ev3 Robotics Lesson Orchard Challenge (Turns other then 90 Degrees)

Additional Materials
  • Masking Tape
  • Measuring Tape/Ruler
Board Set Up

You need to create 3 diagonal lines, and a box of masking tape on your testing surface as shown below:

img_1742

Challenge

In this challenge students will program their robot to start in the box, and navigate around the tape without running over it. Once the robot has navigated the “orchard” it will return to the box. This challenge is designed to simulate a real world task performed by a robot. Oftentimes commercial fruit crops need to be sprayed with insecticide or some other chemical in order to produce to their fullest potential. This job is performed by a self driving robotic tractor in some cases.

One very nice thing about this challenge is how simple it is to modify complication. I have asked my students to add robotic arm control to this program to simulate a sprayer, and have allowed students to use only one side for the sprayer for example. However you differentiate this lesson in your classroom is fine, I use this challenge as the performance assessment for the first two lessons in my robotics unit. Below you will see the rubric I use for grading.

 

movement-assessment-rubric-orchard-challenge

Final Note

The standards for this lesson are discussed in Lesson 1, as are some general how to teach Ev3 Programming items. I hope you have found this Ev3 Robotics Lesson useful. If you have, please share this article with everyone you know. To keep current on everything we do here, please sign up for notifications below.