When you hear the task "program the robot to follow a black line", most probably you will imagine a program operating as follows:
This program seems logical and will probably work. However, the second task is quite hard, if not impossible. The part where the sensor reads black and goes forward is easy:
However, the part where the sensor is outside of the line is impossible. Let us say that the robot is on the right side of the line:
Then it has to turn left to return to the line. Now, if the sensor is on the left side of the line:
It has to turn right to return to the line. That is great but the values the sensor reads on both sides of the line are close if not the same. Hence the robot will not know if it has to turn left or right.
That is why, when we say that we program the robot to follow a line, we usually lie. The truth is that the robot is not following the line but one of its edges.
The edge is an imaginary line which separates the line from the other part of the field (the red dotted lines on the image above). So the line has two edges - one on its left side and one on its right side.
When we are following the edge of the line, the robot, which uses only one color sensor, knows if it is on the left or on the right side of the edge it follows. For clarity, let us assume that the robot is following the right edge of the line. So, if the sensor reads black, this means the robot is on the left side of the edge and should turn right:
If the sensor reads white, it is on the right side of the edge and should turn left:
Having said that, the program for following a black line should look like this - if the sensor reads black, it turns right, otherwise it turns left. Of course, this check is repeated in a loop. Go through the next few exercises and then try and see if the robot follows the line successfully.
This Tutorial is used in the following courses and lessons
If you are working with students and you want to introduce Robotics to your class or you want to mentor a FLL team, but you are insecure about your technical knowledge in the Robotics field, then this is the right place for you. Having in mind teachers' busy schedule, we have design two different schedules and added an option to design one just for you. FLLCasts's Mindstorms EV3 Robotics Online Training is the perfect match for any teacher.
After the completion of each task the participant has to upload his solution for verification.
Today we will focus on another block which will allow our robots to make decisions. This block is in the Flow Control palette and is called “Switch”.
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.
If you are working with students and you want to introduce Robotics to your class or you want to mentor a FLL team, but you are insecure about your technical knowledge in the Robotics field, then this is the right place for you. Having in mind teachers' busy schedule, we have design two different schedules and added an option to design one just for you. FLLCasts's Mindstorms EV3 Robotics Online Training is the perfect match for any teacher.
After the completion of each task the participant has to upload his solution for verification.
In this episode, we introduce a LEGO Mindstorms EV3 version of competition robot construction. It is a modular construction, with medium motor for additional attachments and two light or colour sensors for orientating on the field.
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.
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.
In the next lesson we usually do a graduation. Write down your impressions about the students and the reasons why they have the grades you gave them.
An introduction to the SPIKE Prime set! In this course you will have access to 7 3D instructions for SPIKE Prime robots, exploring the possibilities of the base set. After you build them, you can give them life using our cool programs that do various things, from just moving the robot forward, to finding the closest object to it.
After that, if you are up to the challenge, we have prepared some hard additional tasks. They aim to make you research solutions for modifications to the program and the robot. Of course, you can always make your own additions to the robots and have fun with it!
