Introduction
Do you know what a labyrinth is?
A labyrinth is a complex, confusing structure designed to make people lose their way in its winding pathways.
The story behind the word "Labyrinth" is fascinating and is today's topic! It originates from an ancient Greek myth about the Labrys. According to legend, King Minos of Crete had a magical double-sided battleaxe called the Labrys. To protect it, he had the architect Daedalus build a massive maze and placed the Labrys at its center. This labyrinth also imprisoned a terrifying beast called the Minotaur, a half-bull, half-man creature. After defeating Athens in a war, King Minos demanded that every nine years, seven boys and seven girls be sent to be fed to the Minotaur.
Eventually, the hero Theseus, founder of Athens, traveled to Crete to slay the beast and save the children. King Minos' daughter, Ariadne, fell in love with Theseus and gave him a golden ball of thread to help him navigate the labyrinth. With this and Daedalus' help, Theseus solved the labyrinth, slew the Minotaur, retrieved the Labrys, and escaped with the children and Ariadne.
The myth has some basis in reality. Archaeologists have found remnants of a labyrinth on Crete, and many coins from the period feature an engraved labyrinth, often with a Minotaur inside. The Labrys was also a symbol of Crete and appears on numerous archaeological finds.
Navigate through a labyrinth
There is the classic robotics task - maze solving, or navigation in a labyrinth.
Today we will start with an introductory challenge - navigation in a known tunnel.
The challenge
We have a tunnel of boxes with alternating left and right turns. The problem is that the distance between the turns will change before every start. How will the robot navigate the labyrinth without knowing the distance to the next turn in advance?
Our approach
To solve today’s task, we will use a touch sensor to detect when the robot reaches the next wall. The robot will essentially feel its way through the tunnel.
We will learn to perform a spin turn, which is highly effective in tight spaces.
We will also review how to use sound blocks and program the robot to announce the direction of its turns.
Construction and Theory
Today's task is for the robot to solve a labyrinth using a touch sensor. Imagine if Theseus had one of those! :D
The touch sensor is placed in front of the robot to detect when it hits a wall, signaling it to turn. Additionally, the robot uses larger wheels. What effect do these wheels have on the robot?
Tembias - LEGO SPIKE Prime touch sensor robot
In Guarani, "tembias" means "stories."
The robot moves using two motors with large wheels. At the front, it has a force sensor to detect obstacles.
After building the robot, close the box to keep the desk clear.
- Gather all the parts from the desk and put them back in the box.
- Close the box and move it aside so it's out of your way.
Programming and Theory
In this lesson, you will learn a fundamental concept for using every sensor in SPIKE Prime: the wait until block. With this, you will learn how to solve a maze using a touch sensor—no string needed!
How to use the wait until block in LEGO SPIKE Word Blocks software
You already know what wait for seconds does, but do you know what wait until does?
Wait until is the sixth block in the orange Control section.
It is used in combination with a Logic block, which you place inside the wait until block. The logic block specifies what the wait until block is waiting for!
Logic blocks are mainly found in the Sensors and Operators sections.
Logic blocks can be either True or False, and the wait until block waits until their condition is True. For example, if we use the force sensor logic block, as shown in the picture above, it will be False if the sensor isn't pressed and True if the sensor is pressed. So the block above will wait until the force sensor is pressed!
Navigation in a tunnel
A detailed description of today's main challenge: Navigating a Tunnel
Known turns
A known turn means you know the sequence of the turns. You are solving a task for a tunnel with consistent 90-degree turns in the following order: right, left, right, left.
We might say you are programming a highly specialized robot. As you advance in robotics, you will learn how to navigate tunnels with unknown turns and even real labyrinths.
Unknown distance
Nevertheless, this task is not easy. You know the next turn is right, but you do not know how far it is.
Your robot should be able to handle both very short and very long tunnels using the same program.
A Tight Tunnel
It is possible that the tunnel is very tight, making it difficult for your robot to turn. Which turn should you use in this situation?
Various Types of Turns
Today, you can practice various types of turns. You already know the three types of turns with two motors and a bearing wheel. Use them accordingly.
Bonus Tasks
These tasks are optional and can only be solved by students who have completed all the main tasks and received confirmation from their teacher.
Tasks to finish a class
- Take pictures and make videos of your robots.
- Disassemble and arrange the robot .
- Arrange your workplace :
- It is important to arrange the electronics of the robots on the cover of the box.
- Wind up the programming cable so that it is assembled.
- Wind up the mouse cable around the mouse.
- Wind up the cable of the laptop charger in a way that your teacher will show you.
- When you turn off the computer, leave it next to the robot box.
- Turn off all programs on your computer.
- Exit FLLCasts.
- Shut down your computer.
- Put your chair under the desk.