Preliminary Project Description

Racecars

We are planning on building two racecars for our final project. Each player will control their respective car using a joystick. The joysticks will controls what direction the car drives in, whether the car drives in forward or reverse, and at what speed the racecar moves. For this, we will use a two-axis accelerometer. If we decide to change the joystick into a wii-mote type of controller, we will need a three-axis accelerometer and a gyroscope. The cars will have DC motors that turn their wheels, whose PWMs (and thus speeds) will be adjusted in correlation with the distance the joystick is moved from the origin. If the joystick is moved backwards, the duty cycles created by PWM will be decreased to zero and the direction of the DC motor will be changed before the duty cycle is increased again. This can be used as a breaking mechanism, where the player will hold the joystick backwards for a short amount of time to slow down the car before it starts moving backwards, as well as a mechanism for driving in reverse. When the car is turning, one of the wheels will turn faster than the other, and thus its motor will have a larger duty cycle.

The cars will have a starting gate that double as a finish line. It will tell the cars when to move with sequential starting lights. An option is that the cars will not be able to move before the start signal is initiated, so that no false starts will occur. When the race finished, the start/end gate will register which car passed through the gate first, and the result of who won will be displayed on the gate using LEDs.