28-06-2012, 01:48 PM
Building a Line Following Robot
[attachment=25930]
As a programming teacher, I frequently adopt the attitude of "Come inside a programmer's brain!" I can then explain the concept or source code as I would if I did all my thinking out loud. This is helpful to many students because most of my examples do come from my brain or experience. This allows me walk them through the process and to make mistakes or false assumptions, and then correct them as we proceed.
I would like to take that attitude here as I describe the processes I am going through in developing a line-following robot.
This all started recently when I was told I would soon be teaching a class called "Embedded Systems" at my college. When I learned that the chip was a PIC16F series microcontroller, and that there would be a development board, similar to the Handy Board, I realized I had some experience in this area. For my Bachelor's Degree in Electronics Engineering, I had been the programmer for an autonomous robot that used a Motorola 68HC11, a similar chip.
It occurred to me that the "Final Exam" for this class could very well be a line following robot. The project is simple enough to be "do-able" in college electronics and programming students, complex enough that it would be a challenge and learning experience for students. Line followers are popular enough in robotics clubs, that students could find plenty of supporting material on the Internet. I Googled “line following robot” and found many good leads and great sites describing what is going on with line following robots.
WHAT’S OUT THERE?
The first task appeared to be taking a look at what types of line following contests were out there. It made sense to me that the ultimate test of any robot is to have it compete against other robots. I searched and looked at many articles, photos and videos. Here’s what I saw.
The courses are either black lines (usually ¾ inch electrical tape) on white background, by far the most common, or white lines on black background. Since it was a simple matter to adjust the robot
behavior for either, I elected to work with black lines.
NARROWING THE CRITERIA
With what had observed, and what I know, the following criteria begin to emerge:
The robot has to be fast. In the videos on the net and on YouTube.com I observed some pretty fast robots!
The robot has to properly navigate difficult courses. It didn’t make sense to design a robot for an “easy” course, only to find later that I had to discard the entire project because it wasn’t able to do a more demanding task.
INPUT SENSOR SELECTION
After many trips to Google, I started narrowing this choice. I was not impressed by "big" solutions where large, unfocused lights or LEDs flooded the floor with light. I saw several of these solutions that required additional shielding and caused problems because the total light "under the hood" was too intense.
[attachment=25930]
As a programming teacher, I frequently adopt the attitude of "Come inside a programmer's brain!" I can then explain the concept or source code as I would if I did all my thinking out loud. This is helpful to many students because most of my examples do come from my brain or experience. This allows me walk them through the process and to make mistakes or false assumptions, and then correct them as we proceed.
I would like to take that attitude here as I describe the processes I am going through in developing a line-following robot.
This all started recently when I was told I would soon be teaching a class called "Embedded Systems" at my college. When I learned that the chip was a PIC16F series microcontroller, and that there would be a development board, similar to the Handy Board, I realized I had some experience in this area. For my Bachelor's Degree in Electronics Engineering, I had been the programmer for an autonomous robot that used a Motorola 68HC11, a similar chip.
It occurred to me that the "Final Exam" for this class could very well be a line following robot. The project is simple enough to be "do-able" in college electronics and programming students, complex enough that it would be a challenge and learning experience for students. Line followers are popular enough in robotics clubs, that students could find plenty of supporting material on the Internet. I Googled “line following robot” and found many good leads and great sites describing what is going on with line following robots.
WHAT’S OUT THERE?
The first task appeared to be taking a look at what types of line following contests were out there. It made sense to me that the ultimate test of any robot is to have it compete against other robots. I searched and looked at many articles, photos and videos. Here’s what I saw.
The courses are either black lines (usually ¾ inch electrical tape) on white background, by far the most common, or white lines on black background. Since it was a simple matter to adjust the robot
behavior for either, I elected to work with black lines.
NARROWING THE CRITERIA
With what had observed, and what I know, the following criteria begin to emerge:
The robot has to be fast. In the videos on the net and on YouTube.com I observed some pretty fast robots!
The robot has to properly navigate difficult courses. It didn’t make sense to design a robot for an “easy” course, only to find later that I had to discard the entire project because it wasn’t able to do a more demanding task.
INPUT SENSOR SELECTION
After many trips to Google, I started narrowing this choice. I was not impressed by "big" solutions where large, unfocused lights or LEDs flooded the floor with light. I saw several of these solutions that required additional shielding and caused problems because the total light "under the hood" was too intense.