The key task of today's lesson is to program the robot to stop on a third black line. The students will face a lot of challenges here and will probably not cope with the task on their own.
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- #858
- 30 Mar 2018
In most cases the program they will make will look somewhat similar to the following one:
Now you should interrupt students and together discuss how to properly program the robot to stop on the third black line and find the issue with the program at hand. Highlight that their program is technically correct. Then, you can go through the program together, as if you were the robot and execute all the commands in the program. You should point out that after the robot stops on a black line for the first time, its next starting point is already a black line. So, the second time the program runs, the robot travels no distance because it is already on black.
In order to be sure that the robot has detected a new line and not the old one, robots must reach the end of the line.
Younger or impatient students will program the move block to go forward for a fraction of rotation or for a few seconds. That is a totally valid solution. Give them time to experiment and see how it works.
Then, show them the drawback that solution has when the lines have different width or when the space between the lines is less than the distance the robot moves blindly. The period when a robot uses rotations, degrees or seconds is the time when the robot is deaf, blind and feels nothing.
A universal approach to the challenge is to sense when one line ends and when another one starts.
To make sure that the black line detected by the sensor is a new one, students have to add a wait block to wait for a color other than black. Therefore, the final program should look like this:
Courses and lessons with this Tutorial
This Tutorial is used in the following courses and lessons
Robotics with LEGO - Level 1.5 - Spy games
The second level of the Robotics with LEGO curriculum for students from fifth to twelfth grades.
Students build multiple robots with thread chains and become familiar with the physical concepts of momentum and center of gravity. The concept of gears, their use and basic constructions involving gears are studied.
The new concept of "condition" is introduced in programming. Robots are becoming smarter as they can make complex decisions on their own. "Spy robots" follow their targets and avoid being noticed. This level introduces the light sensor which the robots use to recognize the colors of the objects they are looking for. Robots can stop on a black line and follow a route marked with a colored line on the floor.
The spy's most complex mission in the end of the level is to turn into a sumo wrestler and defeat any other robot in the ring.
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Level B2. "Military Technologies". Robotics with LEGO
The firfth level of the Robotics with LEGO curriculum for students in second, third or fourth grades.
The students build many robots with chain-treads. The Color Sensor is introduced and robots use it to recognize the colors of the objects around them. Students learn about gears, basic gear constructions, and their application. Robots now can stop on a black line and can follow a line using their sensor.
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Lesson 4 - Third black line
Introduction
Key part of the warfare is the intelligence. If two armies are at war, usually one of the two is smaller and will want to apply some secret strategy in order to win the war. In that case the larger army would like to figure out that strategy in order to counter it. Today we build a scout robot. The task of the robot will be to follow an army and find out where is it positioned and what is its plan for action.
Do you know what is key for scouts? Why are they needed?
In order to be able to spot the enemy, the robot will need to follow their tracks. People leave all kinds of tracks and a whole army will leave even more! For instance they would have a campfire, or throw out their cans of beer and most certainly they will leave a lot of trampled grass. However, if they are smart they will cover most of their tracks and that is why our robot should be able to outsmart them!
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