LEGO Robot Drives Thru a Maze

This is a simple, autonomous robot designed to drive thru a maze to an exit. It is built using LEGO Mindstorms EV3. The EV3 Software runs on a computer and generates a program, which is then downloaded to a microcontroller called an EV3 Brick. The programming method is icon-based and high-level. It’s very easy and versatile.

PARTS

• LEGO Mindstorms EV3 set
• LEGO Mindstorms EV3 ultrasonic sensor. It’s not included in the EV3 set.
• Corrugated cardboard for the maze. Two cartons should be sufficient.
• A small piece of thin cardboard to help stabilize some corners and walls.
• Glue and tape to connect cardboard pieces together.
• A red greeting-card envelope to identify the exit of the maze.

TOOLS

• Utility knife to cut the cardboard.
• Steel ruler to aid the cutting process.

MAZE-SOLVING METHOD

There are several methods of navigating a maze. If you are interested in studying them, they are described very well in the following Wikipedia article: https://en.wikipedia.org/wiki/Maze_solving_algori...

I chose the left-hand wall-follower rule. The idea is that the robot will keep a wall on its left side by making the following decisions as it goes thru the maze:

• If it’s possible to turn left, do so.
• Otherwise, go straight if possible.
• If it can’t go left or straight, turn right, if possible.
• If none of the above are possible, this must be a dead end. Turn around.

One caution is that the method could fail if the maze has a loop in it. Depending on the placement of the loop, the robot could keep going around and around the loop. A possible solution for this problem would be for the robot to switch to the right-hand wall-follower rule if it realized that it was going in a loop. I didn’t include this refinement in my project.

STEPS FOR BUILDING THE ROBOT

Although LEGO Mindstorms EV3 is very versatile, it allows no more than one of each type of sensor connected to one Brick. Two or more Bricks could be daisy-chained, but I didn’t want to buy another Brick, and so I used the following sensors (instead of three ultrasonic sensors): infrared sensor, color sensor, and ultrasonic sensor. This worked out well.

I tried importing my project from instructables.com but some photos were missing in the import. For the complete project, please go to :

https://www.instructables.com/id/LEGO-Robot-Drives-Thru-a-Maze

This was a fun project. I hope you also find it interesting.