Servo Motors

To rotate the wheels of our vehicle, we used four continuous rotation servo motors. They run on a maximum of 6 volts DC and rotate a full 0 to 180 degrees. An image of the motor is shown below. To attach the rotary encoder, we modified each motor by removing the back plate and attaching a metal rod to the back side of the rotating gear. We then used flexible clear plastic tubing to form a connection between the metal rod and the rotary encoder. A picture of the modification is shown below.

The Atmel Mega644 was used to control and monitor the acceleration and velocity of our vehicle. The major features of the Mega644 that were used for our project included one 8-bit timer, 4 PWM output pins, one Analog to Digital converter, and four standard I/O pins. The Mega644 chip was built on a prototype board provided by Bruce Land. It features an easy way to power, attach a crystal clock, connect to a RS232 interface, and program the Atmel chip. A schematic of the board can be found here.

We chose to attach the optional interface for serial communication because it provided critical debugging features and we had extra money to budget.