2WD蓝牙控制的汽车的问题无法停止

因此，我正在为2WD蓝牙控制的足球车创建代码。当我向前推进时，它会向前朝前。

我尝试更改代码几次，例如：

if( val == '1') // Forward
    {
      digitalWrite(m1a, HIGH);
      digitalWrite(m1b, LOW);
      digitalWrite(m2a, HIGH);
      digitalWrite(m2b, LOW);
      delay(1);
      digitalWrite(m1a, LOW);
      digitalWrite(m2a, LOW);
    }

to：

if( val == '1') // Forward
    {
      digitalWrite(m1a, HIGH);
      digitalWrite(m1b, LOW);
      digitalWrite(m2a, HIGH);
      digitalWrite(m2b, LOW);
      delay(200);
      digitalWrite(m1a, LOW);
      digitalWrite(m2a, LOW);
      digitalWrite(m1b, LOW);
      digitalWrite(m2b, LOW);
    }

这是完整的代码：

// Starting of Program
#include <SoftwareSerial.h>
SoftwareSerial mySerial(10,11);
int m1a = A3;
int m1b = A4;
int m2a = 3;
int m2b = A5;
char val;
void setup() 
{  
pinMode(m1a, OUTPUT);  // Digital pin 10 set as output Pin
pinMode(m1b, OUTPUT);  // Digital pin 11 set as output Pin
pinMode(m2a, OUTPUT);  // Digital pin 12 set as output Pin
pinMode(m2b, OUTPUT);  // Digital pin 13 set as output Pin
mySerial.begin(9600);
}
void loop()
{
  while (mySerial.available() > 0)
  {
  val = mySerial.read();
  mySerial.println(val);
  }
  if( val == '1') // Forward
    {
      digitalWrite(m1a, HIGH);
      digitalWrite(m1b, LOW);
      digitalWrite(m2a, HIGH);
      digitalWrite(m2b, LOW);
      delay(1);
      digitalWrite(m1a, LOW);
      digitalWrite(m2a, LOW);
    }
  else if(val == '2') // Backward
    {
      digitalWrite(m1a, LOW);
      digitalWrite(m1b, HIGH);
      digitalWrite(m2a, LOW);
      digitalWrite(m2b, HIGH); 
      delay(200);
      digitalWrite(m1a, LOW);
      digitalWrite(m1b, LOW);
      digitalWrite(m2a, LOW);
      digitalWrite(m2b, LOW); 
    }
    else if(val == '3') //Left
    {
      digitalWrite(m1a, LOW);
      digitalWrite(m1b, HIGH);
      digitalWrite(m2a, HIGH);
      digitalWrite(m2b, LOW);
      delay(200);
      digitalWrite(m1a, LOW);
      digitalWrite(m1b, LOW);
      digitalWrite(m2a, LOW);
      digitalWrite(m2b, LOW); 
    }
    else if(val == '4') //Right
    {
      digitalWrite(m1a, HIGH);
      digitalWrite(m1b, LOW);
      digitalWrite(m2a, LOW);
      digitalWrite(m2b, HIGH); 
      delay(200);
      digitalWrite(m1a, LOW);
      digitalWrite(m1b, LOW);
      digitalWrite(m2a, LOW);
      digitalWrite(m2b, LOW); 
    }
    else if(val == 'S')
    {
      digitalWrite(m1a, LOW);
      digitalWrite(m1b, LOW);
      digitalWrite(m2a, LOW);
      digitalWrite(m2b, LOW); 
      delay(1000);
      digitalWrite(m2a, HIGH);
    }
}
// End of program

没有错误按摩，请帮助...我正在手机上使用此应用，最后11行代码，(val =='s'(用于应用程序中的停止按钮。

我只需要在按下按钮时才移动，并在没有按下时停止。它不需要停止按钮。