     // read motor states and drive motors    
     for(i = 0; i < 2; i++)
     {
-      if (abs(motor_drive_present[i] - motor_drive_target[i]) < 7)
+      if (abs(motor_drive_present[i] - motor_drive_target[i]) < MOTOR_RAMP_THHRESHOLD)
       {
         // if close to target, set to target
         motor_drive_present[i] = motor_drive_target[i];

#define XBEE_COMMAND_TURN_RIGHT     2

#define FULL_SPEED                  255
#define TURN_SPEED                  50

#define LEFT_MOTORS                 0
#define RIGHT_MOTORS                1

#define MOTOR_FORWARD_TURN          33
#define MOTOR_REVERSE_FULL          44
#define MOTOR_REVERSE_TURN          55
#define MOTOR_RAMP_STEP             25
#define MOTOR_RAMP_THHRESHOLD       50

#define BUTTON_MASK                 0x10
#define JOYSTICK_MASK               0x0F
