Arduino Serial.read() 只读取第二个输入

Question

每当我在串行监视器中输入时，Arduino 只读取第二个用户输入。

我尝试创建一个 4 个电机（A、B、C、D），当我输入速度然后输入电机字母时它会移动。例如（180a）以 180 的速度移动电机。

我不明白为什么序列号只在我第二次输入命令时读取。它有效，但这是唯一的问题。

这是我的代码：

// Pins for motor A
const int a_pwm_pin = 9;
const int a_dir1_pin = 8;
const int a_dir2_pin = 7;

// Pins for motor B
const int b_pwm_pin = 10;
const int b_dir1_pin = 11;
const int b_dir2_pin = 12;

// Pins for motor C
const int c_pwm_pin = 4;
const int c_dir1_pin = 3;
const int c_dir2_pin = 2;


// Pins for motor D
const int d_pwm_pin = 5;
const int d_dir1_pin = 6;
const int d_dir2_pin = 13;

void setup() {

// Set up pins for motor A
pinMode(a_pwm_pin, OUTPUT);
pinMode(a_dir1_pin, OUTPUT);
pinMode(a_dir2_pin, OUTPUT);

// Set up pins for motor B
pinMode(b_pwm_pin, OUTPUT);
pinMode(b_dir1_pin, OUTPUT);
pinMode(b_dir2_pin, OUTPUT);
  
// Set up pins for motor C
pinMode(c_pwm_pin, OUTPUT);
pinMode(c_dir1_pin, OUTPUT);
pinMode(c_dir2_pin, OUTPUT);
  
// Set up pins for motor D
pinMode(d_pwm_pin, OUTPUT);
pinMode(d_dir1_pin, OUTPUT);
pinMode(d_dir2_pin, OUTPUT);
  
Serial.begin(9600);

}

void loop() {
    
if (Serial.available() > 4)
  {
    int speed;
    delay(2);
    char command = Serial.read();
    Serial.print(command);
    switch (command)
    {
    case 'a': speed = Serial.parseInt();
      // A Motor Movement
      aforward(speed);
      break;

    case 'b': speed = Serial.parseInt();
      // B Motor Movement
      bforward(speed);
      break;
      
    case 'c': speed = Serial.parseInt();
      // C Motor Movement
      cforward(speed);
      break;

    case 'd': speed = Serial.parseInt();
      // D Motor Movement
      dforward(speed);
      break;

    default: Serial.println("");
    }
  }

}

// Drive forward
void aforward(int speed) {

// Check to make sure speed is 0-255
if ( speed < 0 ) {
speed = 0;
}
if ( speed > 255 ) {
speed = 255;
}

// Motor A forward
digitalWrite(a_dir1_pin, HIGH);
digitalWrite(a_dir2_pin, LOW);
analogWrite(a_pwm_pin, speed);

}

void bforward(int speed) {

// Check to make sure speed is 0-255
if ( speed < 0 ) {
speed = 0;
}
if ( speed > 255 ) {
speed = 255;
}


// Motor B forward
digitalWrite(b_dir1_pin, HIGH);
digitalWrite(b_dir2_pin, LOW);
analogWrite(b_pwm_pin, speed);

}

void cforward(int speed) {

// Check to make sure speed is 0-255
if ( speed < 0 ) {
speed = 0;
}
if ( speed > 255 ) {
speed = 255;
}

// Motor C forward
digitalWrite(c_dir1_pin, HIGH);
digitalWrite(c_dir2_pin, LOW);
analogWrite(c_pwm_pin, speed);

}

void dforward(int speed) {

// Check to make sure speed is 0-255
if ( speed < 0 ) {
speed = 0;
}
if ( speed > 255 ) {
speed = 255;
}

// Motor D forward
digitalWrite(d_dir1_pin, HIGH);
digitalWrite(d_dir2_pin, LOW);
analogWrite(d_pwm_pin, speed);
}

Answer 1

所以您的代码存在一些问题。首先，你的 serial.available if 语句在第 5 个字符之前不会为真，“> 4”是“大于 4”使得“大于或等于”将解决该问题。另一个问题是你的在每个“case”语句中使用 Serial.parseInt()。将它移到顶部，这样它只有运行一次。我创建了一个工作循环，您可以将其复制到您的项目中，一切都应该有效。祝你有美好的一天，如果有任何问题或您可能有任何问题，请发表评论。

void loop(){
if (Serial.available() >= 4)
  {
    delay(2);
    int speed = Serial.parseInt();
    char command = Serial.read();
    Serial.print(command);
    switch (command)
    {
    case 'a':
      // A Motor Movement
      aforward(speed);
      break;

    case 'b':
      // B Motor Movement
      bforward(speed);
      break;
      
    case 'c':
      // C Motor Movement
      cforward(speed);
      break;

    case 'd':
      // D Motor Movement
      dforward(speed);
      break;

    default: Serial.println("");
    }
  }
}

Arduino Serial.read() 只读取第二个输入

Arduino Serial.read() only reads the second input

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