path remembering car

Projects Programming
9

PaulS:
With 4 motors, pins 3, 5, 6, and 11 are used. You can't then use pin 3 as an interrupt pin, too.

so how I dont use pin 3 as an interrupt?
and is this what you meant by changing the coder to a volatile?

#include <AFMotor.h> 
AF_DCMotor motor1(1, MOTOR12_64KHZ); 
AF_DCMotor motor2(2, MOTOR12_64KHZ); 
AF_DCMotor motor3(3, MOTOR12_1KHZ); 
AF_DCMotor motor4(4, MOTOR12_1KHZ); 
const int pingPin = 19; 
#define LEFT 0
#define RIGHT 1

volatile long coder[2] = {
  0,0};
int lastSpeed[2] = {
  0,0}; 
void setup() { 
  Serial.begin(9600);           // set up Serial library at 9600 bps 
  motor1.setSpeed(200);         // Set the speed for the motors (255 is the maximum)  
  motor2.setSpeed(200); 
  motor3.setSpeed(200); 
  motor4.setSpeed(200); 
  attachInterrupt(LEFT, LwheelSpeed, CHANGE);    //init the interrupt mode for the digital pin 2
  attachInterrupt(RIGHT, RwheelSpeed, CHANGE);   //init the interrupt mode for the digital pin 3
}