2灰度传感器，4电机小车循迹代码

以下是一个基于Arduino的2灰度传感器、4电机小车循迹代码：

//定义引脚
#define rightMotor1 A0
#define rightMotor2 A1
#define leftMotor1 A2
#define leftMotor2 A3
#define rightSensor A4
#define leftSensor A5

//定义变量
int sensorValueL; //左传感器的值
int sensorValueR; //右传感器的值
int threshold = 500; //传感器阈值
int motorSpeed = 255; //电机速度

void setup() {
  pinMode(rightMotor1, OUTPUT);
  pinMode(rightMotor2, OUTPUT);
  pinMode(leftMotor1, OUTPUT);
  pinMode(leftMotor2, OUTPUT);
  pinMode(rightSensor, INPUT);
  pinMode(leftSensor, INPUT);
}

void loop() {
  sensorValueL = analogRead(leftSensor);
  sensorValueR = analogRead(rightSensor);

  //左右传感器都在黑线上时
  if (sensorValueL < threshold && sensorValueR < threshold) {
    digitalWrite(leftMotor1, HIGH);
    digitalWrite(leftMotor2, LOW);
    digitalWrite(rightMotor1, HIGH);
    digitalWrite(rightMotor2, LOW);
  }
  //左传感器不在黑线上，右传感器在黑线上时
  if (sensorValueL > threshold && sensorValueR < threshold) {
    digitalWrite(leftMotor1, LOW);
    digitalWrite(leftMotor2, HIGH);
    digitalWrite(rightMotor1, HIGH);
    digitalWrite(rightMotor2, LOW);
  }
  //左传感器在黑线上，右传感器不在黑线上时
  if (sensorValueL < threshold && sensorValueR > threshold) {
    digitalWrite(leftMotor1, HIGH);
    digitalWrite(leftMotor2, LOW);
    digitalWrite(rightMotor1, LOW);
    digitalWrite(rightMotor2, HIGH);
  }
  //左右传感器都不在黑线上时
  if (sensorValueL > threshold && sensorValueR > threshold) {
    digitalWrite(leftMotor1, HIGH);
    digitalWrite(leftMotor2, LOW);
    digitalWrite(rightMotor1, HIGH);
    digitalWrite(rightMotor2, LOW);
  }
  //电机速度
  analogWrite(leftMotor1, motorSpeed);
  analogWrite(rightMotor1, motorSpeed);
}

其中，`rightMotor1`、`rightMotor2`、`leftMotor1`、`leftMotor2`是4个电机控制引脚，`rightSensor`、`leftSensor`是2个灰度传感器引脚。在`loop()`函数中，通过读取传感器的值来判断小车应该往哪个方向前进，并控制电机的转动方向和速度。如果左右传感器都在黑线上，则小车直行；如果左传感器不在黑线上，右传感器在黑线上，则小车右转；如果左传感器在黑线上，右传感器不在黑线上，则小车左转；如果左右传感器都不在黑线上，则小车停止。