Car Guide
This guide was written a few years back to be used with RC cars. We no longer use RC cars but we leave this here in case you want to start up miniFIRST using them.
The following guide to starting miniFIRST like events was written by Kenneth Stafford. Questions and comments are welcome.
While many options exist to involve high school students with fun, motivating design projects (Lego Mind-Storms and FIRST as exaples), most require a significant financial commitment and consequently do not reach a large student population. "SAVAGE SOCCER" was designed by WPI students to be an exciting, satisfying project that could involve large groups of students at very little cost.
The robots are based upon small scale Radio Shack radio-remote-controlled cars. Since the entire game is played on a regulation-sized Ping-Pong table, small, slow cars are preferable. For the past two years we have used a model called the "Triton." This car has about a 5 ¼ inch wheelbase and is capable of non-proportional forward, reverse, left turn and right turn. They could be purchased in 1998 for under $20 each.
Modifications to the Cars
We planned on using the cars year after year, therefore no permanent team modifications are allowed. Upon receipt of the cars, we removed the bodies and installed spacers over the original, three chassis mounting holes to provide a level fastener surface that clears the cars' electronics. These spacers can be made of 3/8 inch wood or plastic dowels, drilled and/or tapped for #8 machine screws. Upon this we mount a 6 x 9 inch clear sheet of 3/16 (4 mm) lexan that extends above and just beyond the car's four wheels. This cover is fastened to the leveling dowels by #8 machine screws and has cutouts for the antenna and car motor housing. This lexan cover is expendable and serves as a mounting platform for all design details that the teams come up with, as well as a uniform height bumper.
These cars come in only two, non-changeable, operating frequencies (27 or 53 MHz). When purchasing the cars, pay attention to get a same number of each frequency to provide the maximum interoperability. We engrave a serial number on each car chassis and matching transmitter that is coded to the operating frequency (ie even numbers are 27 MHz, odd are 53 MHz).
Playing Field
Each year we modify the playing field slightly to create new challenges. Constants include: ten ping-pong balls for each robot team (ie ten white balls and ten red balls), "soccer" goals at each end of the playing surface, tilted corners to prevent balls from being trapped, and an eight inch high border surrounding the surface. Options include obstacles (either blocks or mounds) that must be navigated over or around, secondary scoring locations (eg an elevated basket), or an additional, tie-breaking neutral ball.
Tournament Operation
We use ten teams with four students per team. To encourage mixing, we insist that no team come from a single academic year. We further require (or arrange through somewhat devious rules!) that all four members drive the car in each round. At the beginning of the tournament we go through a thorough inspection of each car to insure all size, weight, and material specifications are met. After each team has been allowed some practice time, we collect all transmitters to insure against spurious signals. The first rounds are assigned odd teams against even so each car will be on a separate frequency. As the rounds progress, judicious placement will normally prevent two cars of the same frequency from coming up against each other. When that does inevitably occur in the latter stages of the tournament, we simply have a respective team exhibit their ability to swap their chassis within the five-minute design criteria.
Our ten-team, double elimination tournaments require about 20 matches and take about 2 hours to run.
Overall Comments
One of the most frustrating possibilities in any "robot" tournament is that one or more robots will simple not move. By taking the driveline out of the design exercise, students of all abilities will at least be able to drive around and herd balls. These RC cars have proven to be very reliable and robust. By adding features like extra motors and switches each year, students have come up with some remarkably innovative solutions without having to spend design time simply coming up with a driveable chassis.
After our initial outlay of approximately $250 for 10 cars, batteries, and lexan sheet, we budget $50 a year extra to purchase extra equipment for the design kits (eg accessory motor, battery clips, and switches).
Although specifically designed for high school students, this concept is certainly scalable to middle school (perhaps with high school student mentors). We had intended and have found that participation in SAVAGE SOCCER in a great lead-in and interest-builder toward more demanding design projects.
Maintained by savage@wpi.eduLast modified: Oct 31, 2004, 09:26 EST