1. EV3 Programming guide to “Following”
This tutorial will show how to program basic line, wall and angle following using the retail version of the Lego MindStorms software with the Gyro and Ultrasonic sensors added.
By Chris Baker, Coach of the Seaford Sea Lions, FLL Team #92

2. These are the two basic blocks needed to start “following
These are the two basic blocks needed to start “following.” A switch block inside a loop block.
This is not the only way to move around the FLL challenge map, it is just a solid approach. There are infinite variations to explore!

3. This is a basic black/white line follow
This is a basic black/white line follow. We are not following the line, we are following the edge of the line. This may not work exactly for you as displayed. Your motors may not be in these ports and they may be reversed or upside down.
Also remember the color sensor is very sensitive to ambient light.

4. This is a detail of the line follow
This is a detail of the line follow. You should always check every port every time you add a block, they will probably not be correct when you place them.
This line follow will end after 2.5 motor rotations.

5. This is a basic wall follow
This is a basic wall follow. Very similar to the line follow, just using the ultrasonic sensor instead of color.
It follows the wall at distance of 4cm from the sensor.
This loop ends with the touch sensor being pressed.

6. This is a 90° turn using the Gyro sensor
This is a 90° turn using the Gyro sensor. Then following that angle until the touch sensor is pressed.
We do not need to reset the motor rotation sensor here because we are not using it to measure rotations anywhere.

7. Things to remember:
Always check your ports, especially if you have unexpected results.
Reset your sensors before you use them to measure.
The distance you travel is dictated by the size of your wheels.
Don’t be afraid to experiment, your team will learn by failing.
There are many different ways to solve challenges, don’t get stuck using just one way. If it not working, start over with a different approach.
Read the Coach’s manual and check for game updates regularly.

8. More things to Remember:
Reset your sensors on the way to the competition table.
Don’t put your sensor reset too close to the programming block that is using it.
There is more than one right answer to every challenge. It’s up to you to find the one that works for you.
Learn the core values!