2. Lesson 2 - Tidal waves

Introduction to the LEGO set

Regarding the parts of our robots

This is what one of our easiest robots looks like:

EasyBot

Before we begin construction, we will take a look at some of the parts of the robot.

 

Motors

Motors

These are the "legs" or "muscles" of the robot.

 

Microcontroller (Brick)

LEGO SPIKE Brick

LEGO calls that part "the intelligent brick". You can think of it as the "brain" of the robot. However, it is a microcontroller or a small computer where you can upload the programs you have created from a regular computer. Then, based on the programs, the brick can read data from the sensors and operate the motors.

 

LEGO Technic parts

Some of the main LEGO Technic parts in the LEGO Mindstorms SPIKE set

There are several parts in the image above. Can you match the names to the parts?

• Tire
• Rim
• Double Black Pin
• Triple Long pin
• Bush
• Gear
• Beam
• Axle
• Axle pin

Names of some of the important and common pieces in LEGO Mindstorms set

We will cover the names and the basic usage of the parts in our typical robot.

Let's make sure we all use the same names for the same parts

Names for Pins

• black pin, double pin
• blue pin, long pin, triple pin
• blue axle pin (axle and pin transition)
• torch pin (pin with cross hole)

Names for Beams

• "5 holer" or "15 beam"
• big and small L-beams
• double angular beam

Parts for movement

• Rims (thin rim, wide rim)
• Pulleys
• Tires and Rims form Wheels

Parts for spatial rotation

• Beam with pins
• Angular beam with Pins

Learn the names of LEGO parts in a fun way

Executing more than one command with LEGO SPIKE Prime Word Blocks

Most programs we write require several commands for the robot to execute to complete its task. Here's how to do it with SPIKE Prime Word Blocks software!

To make a program of multiple blocks, we first need to place one block with a command, for example, move 50 cm forward. Then, in the same way, we take another block and place it directly under the previous one.

When we add blocks this way, they are executed one after the other from top to bottom. That means the program in the picture would move the robot forward 50 cm and then back 50 cm. We can then place as many blocks as we need for the robot to complete the task correctly.

Best practices for creating long programs by trial and error

Now that you have tried and solved a challenge involving a series of instructions, we would like to share a few best practices.

Try blocks one by one

It is a bad practice to place several blocks before testing your program. The problem is that when there is an error, you can't pinpoint which block causes the problem.
 

Understand the challenge

To solve a task correctly, you must understand what is expected from you. So, you should articulate how you understood the challenge and ask your teacher if that understanding is correct.
You can also ask us in the comments section below.
 

Test each step of the program with the robot

This is the most important message we have here! Follow this algorithm:

• Place one or two blocks in your program and adjust them;
• Download the program from the computer to the robot;
• Place the robot on the floor and place it at the marked starting position;
• Select the program from the brick menu and start it;
• Observe the results and assess if the robot behaves as desired:
  • If the robot's behavior is "correct" as desired, carry on.
    • Add new blocks to the program to extend it.
  • If there is an error, it is in the new blocks you just added.
    • Correct the error and test it again.
       

Use the download option of the software

Thus, you can control where and when you start the robot. If necessary, you can start the program from the brick several times.

Deleting, Returning and Moving Blocks in LEGO SPIKE Prime Word Blocks software

Have you had a block you want to delete? Or one you want to restore after deletion? Now you will find out how!

To delete a block, we have two options:

1. With the Del button.
2. By moving the block in the palette to the side.

To delete a block with the Del or Delete button, we need to click on it and press the button on the keyboard. This button will always work on the last block you clicked on.

To delete a block with a move, we need to grab it and move it back to the side in the palette, no matter where. Be careful! When we drag a block followed by other blocks, we also drag all the blocks below it and risk deleting a large part of our program.

Another way to delete a block in the middle of several blocks is to move it along with the blocks below it, then grab the blocks below it and return them to the original program. Now, we have isolated the block we want to delete, and we can move it to the side in the palette. We can also use this trick if we want to just move a block instead of deleting it, and it looks like this:

Sometimes, we delete a large part of our program without wanting to or move it and don't remember how it was originally. The tool that fixes such situations is Ctrl+Z, also called "Undo". If you need to undo something, click the Ctrl button and then Z. That undoes an action we did. Pressing it again returns a second action, and we can go on like this probably longer than we ever need to.

Stopping an incorrect program with SPIKE Prime hub

Sometimes, we make a mistake in starting the robot, and we should stop it before its program runs out. Here's how to do it with a SPIKE Prime controller.

Common errors that may lead to the need to stop the robot are:

1. Launching the robot in the wrong direction. Robots can move in any direction, so figure out which direction yours needs to move in and release it so it can do so without a problem. Usually, this direction is away from you.


2. Wrong program launched or problem launching the program. Sometimes, we run the wrong program or a program with an error, and then the robot goes somewhere, and we don't know what's going on. Someone might also push it, and that's where the error comes from.

In all these cases, you should always pick up the robot before it breaks down or gets in the way of others. Then, to stop the program, we press the Middle button on the controller.

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How to set motor ports in LEGO SPIKE Prime Word Blocks software

By default, the motors of the LEGO SPIKE Prime controller connect to ports A and B. What if we want to connect them to other ports? Here's how to change ports in the software.

The block we use to change the ports of the movement motors in the software is in the second-to-last place in the Movement palette. It is called set movement motors to.

The block has one parameter which sets the ports of the two drive motors.

Once we have set the correct ports, our robot will use the new ports as drive motors. Thus, all blocks from the Movement palette will move these two motors.

That block can also be used to reverse the ports, which can be useful if you program the robot to move forward but it still moves backward.