To learn complex programming that includes Bluetooth for communication between NXTs.
NXTs or RCXs
Assorted building materials.
Computer running ROBOLAB or MINDSTORMS
Set up a flat track that is five feet long with a start and finish and set up the ramp.
Collect necessary materials.
Arrange students into groups of 4.
Distribute the necessary materials.
Mechanical advantage of gears
– Small gear on motor, larger gear on wheel and axle for more torque to drive up the ramp
– Large gear on motor, small gear on wheel and axle for more speed to drive across the floor
Weight distribution of vehicle
– More weight on the front of the ramp vehicle
– Less weight for the entire floor vehicle
– Wide wheels for more contact surface area on the ramp vehicle
– Narrow wheels for less contact surface area on the floor vehicle
– Spacing between wheels and sides of vehicle so that the wheels rotate without rubbing
– Large diameter wheels in the front of the ramp vehicle
– Ramp vehicle should be short in length
– Long floor vehicles with four wheels to ensure that the vehicle travels as straight as possible towards the stationary ramp vehicle
- Introduce the activity and tell students that two people in their group will build and program a car to travel as fast as possible on a flat surface, and the other two people will be building a programming a car to drive up a ramp.
- Allow students to build their cars. Remind students that gears might help them build a car that can climb a ramp.
- Have students program their vehicles.
- The first vehicle must travel 5 feet to the base of a ramp and then stop. The students should use time to stop their robot, or use a light sensor if the course is marked with tape.
- When the first vehicle stops, it must send a message to the second vehicle (a number). This will trigger the second vehicle to start climbing the ramp.
- The second vehicle should start climbing the ramp when it receives the message from the first vehicle.
- Communication between RCXs/NXTs may be tricky.
- Use the ‘send mail’ and ‘wait for mail’ icons on the floor and ramp vehicle, respectively.
- Each group should send a different number so as to avoid confusion between RCXs and NXTs.
- Zero the receiving mailbox at the beginning of the program.
- Press run on both robots before starting the relay.
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