This page is here to support students and hobbyists in preparing for line following and line maze contests.
Since all possible contests cannot be covered, this page will focus for a while on these areas:
- Line Following
- Sumo Robot Wrestling
- Lap Timer
There will usually be three different types of line following courses. They will vary in complexity, and therefore the required programming.
Easy Line Following Course
In this type of course, there are straight lines and gentle curves. The curves usually have at least a six inch radius to make it easier for the robot to negotiate turns.
Sometimes, there are also "Proximity Rules", such as - No line can be within six inches of any other line. This makes it easier for a robot to return to a line it left with a smaller chance of straying to a line in a different part of the course.
Here are some photos of "Easy" courses:
Medium Line Following Course
A "Medium" Course adds some difficulty with one or more of the following to provide more of a challenge to the robots navigation.
- Lines in the course cross each other. Often the rule states that crossings will only be at a 90 degree angle.
- Curves in the track can be either greater than 90 degrees, or have a radius less than six inches.
- Sometimes one or more 90 degree turns are included.
Here are a few medium courses:
Difficult Line Following Course
And as you can guess, difficult courses are designed to fool or trip up all but the smartest robots. Here are some of the complications:
- Turns are often greater than 90 degrees and sometimes placed very close together, in stair-step fashion.
- Line crossings are common.
- Sometimes, physical obstacles are introduced, such as:
- An obstacle is placed right on the track, requiring the robot to figure out how to go around the obstacle.
- A "bump" or small hill is made part of the course.
- There can be one or more breaks in the line. To the robot, the line *disappears* and the continued line must be discovered a few inches away. (See the next photo below. The right hand line has several breaks.)
Here are some difficult courses:
Line Following Mazes
A different, but related course is a line maze. In a line maze, the robot is required to proceed from a starting point to the end of the maze. First, let's look at some examples, and then I'll explain.
In the first photo above, the robot would start at the small "T" in the lower left corner, and complete the maze when it gets to the black circle at the top right.
The black circle is so that a *smarter* robot can tell when it has reached the end of the maze.
Notice that a robot trying to traverse the maze would have no choice but to proceed down many dead ends. A robot that made random turns at every intersection might eventually get to the end, but a *smart* robot has a plan.
Usually the rules for mazes state something like "The winner is the robot with the best time in three attempts." This gives the robot the opportunity on the first two runs to record good or bad moves, so that it can traverse the entire maze without turning down any dead end paths.
Different mazes require different strategies to solve the maze. Check this link at Astrolog.org to see an incredibly complete analysis of many different maze algorithms.
Sumo Robot Wrestling
Sumo robots are placed in a ring and the first robot to push the other out of the ring wins.
Go to this page to see the ITT Technical Institute Sumo Contest particulars and rules.
Since both of the robot contests described above could benefit from an accurate timing of the robot completing its mission, it makes sense that a lap timer, using the same chip, would be a related and interesting project. I will ask students to build a Lap Timer for use with these contests.
Here are the Lap Timer specifics in case you are thinking about designing a Lap Timer, or want to communicate with me or my students about this.
Lap Timer Specifications
A lap timer can be used in any robotics contest where finishing any task in the shortest time is part of the scoring system for the contest. Here are the basic specifications for a lap timer that would qualify as Electronics Degree Program Project.
The Lap Timer will comply with the following:
- Microcontroller: PIC16F8680 (or PIC16Fxxxx with similar characteristics)
- Display: Four-Line LCD. (Several 16 character X 4-line LCD's are available on E-Bay or with electronics suppliers for about $12-$15)
- Sensors: Not specified, but laser, IR or optical sensors seem to be a good choice. There need to be two sets of sensors. In a race course where the race course is an oval or a specified closed loop, only one sensor is needed that can record the lap times. For a maze or courses where the start and finish points are in different locations, there needs to be a sensor at the start and another at the finish.
- Input: Switches or push buttons should be used to set one of the following modes:
- Single Lap: Measure the robot passing at the start, then when it completes the lap. Display should say: 03 Min 42.24 Sec
- Three Laps: Display four lines, like:
Lap 1: 01:22.33
Lap 2: 01:11.11
Lap 3: 00:55.44
(03:29.28 would represent 3 Minutes, 29 seconds and 28 hundredths of a second.)
- Single Maze Time: Time from start to finish in MM:SS:hundredths format.
- Three Maze Times: Record three attempts and display as shown above.