Following lines, detecting colors, responding to light. It is still far from "seeing", but the LEGO Mindstorms EV3 & NXT sensors could be very useful when used properly.
In this tutorial we present a way to align your robot to a black line. Go through common difficulties, that the teams face, when they need to align their robot, and provide a solution for them.
Continuing with the Proportional algorithm for following lines. Smooth and stable this is the first part of the PID.
Last part of the series. The final touch of the program makes sure that it works and is following the line with the LEGO Mindstorms EV3 Color Sensor in a smooth and fast way.
This video lesson is a revised version of Episode #1. Matt Gipson requested it in a comment. Using the EV3-G software we have developed a very simple program for following a line with two LEGO MINDSTORMS color/light sensors.
In this tutorial we introduce the basic algorithm for following a line with one sensor and review the algorithm for quickly followwing a black line with one sensor, implementing both with the Mindstorms EV3 robotics kit.
We extract the Proportional Line Following algorithm into a new block with parameters. This allows us to experiment with the Threshold, Constant Speed and Relaxation Coefficient. You can now easily use the block in you other programs without having to implement it.
We list the number of decisions that the robot is making while following the line. Then, we group them and decide on the number of sensors to be used.
In this video lesson I will show you how to follow a black line using just one sensor, but fast enough so that you could use it during any robotics competition without wasting any time.
We follow a line. We start from the Smooth Proportional Line Following program and modify it a little for this program. We follow the line with the middle sensor attached on port 2.
It's inevitable. While following this gapped line we would reach a gap. The robot must somehow understand that there is a gap and must make a decision on what to do. For detecting the gap we use the Rotation Sensor. Not the most popular, but very convenient in many cases. Check out the video.
In this video tutorial I give a step-by-step explanation of how to implement a block for aligning to a line. The block was first used in lesson 28. Aligning to lines is probably the most powerfull way to know the position of the robot on the FLL Competition field and to be able to execute the missions precisely at 100% of the time.
We've detected the gap. It's time to move over it. This is difficult because we have to detect where the line is after the 0.1 meters gap on the line following field.
Next important state is Turn Right with our robot. This happens when we detect a line on the right.
Next state in our state machine programming pattern is the "Turn Left" state and the corresponding behaviour.
We can Turn Right. We can Turn Left. How do we decide which way to go if there are lines both to the left and to the right. Check out the video.
All worked as expected, up until know because the robot got lost. This happens when we turn right and the line does not continue to the right. Now the robot must somehow understand that it is "lost" and escape.
After several questions about the use of the LEGO Mindstorms NXT Light Sensor with the EV3 software, we have decided to go through this problem in this video tutorial and pay special attention to the Raw Sensor Value Block.
We discuss the state of "Lost" and the different ways we could escape this state. We also build the next step of our State machine programming pattern where the next state is determined by the previous state.
In this tutorial, we would implement a program that finds the minimum and maximum value detected by the sensor and stores this two values in an array.
The final video from the course. The robot escapes the state where it is lost. This happens if it can not continue in any direction.
Many times we just upload blocks and leave it up to you to use it. In this tutorial, I would like to show you how to use the implemented blocks. How to import them into the EV3-G software. How to see them in the palette. How to drag and drop them to build a working program.
The robot works on the field and decodes the different colours that represent the rows and the columns.
"Array initialization" is the first step in every program that involves Arrays. This applies to most programming languages and for EV3-G it is a must.
In this tutorial, we would show you how to initialize the array and how to extract this logic in a new block
We would continue from the previous program where we used variables and we would change this to arrays.
