为什么 Arduino mega 和 SIM900 不会发送消息如果我 input/read 到串行监视器，不同的 phone 数字？

Question

我是 arduino 和 gsm sim900 的新手，我目前正在处理这个项目，当学生扫描他们的条形码时，它会将考勤输入数据库并向他们的监护人发送短信。我的问题是，当我尝试输入 "serial.available" 和 "readString(phonenumber)" 等不同的数字时，它不会发送消息，我没有收到任何错误，而且 sim 卡有 e-load/。抱歉语法不好。这是代码：

#include <SoftwareSerial.h>
SoftwareSerial SIM900A(6,7);
String number;
void setup()
{
  SIM900A.begin(9600);
  Serial.begin(9600);
  Serial.println ("SIM900A Ready");
  delay(100);
 Serial.print("Enter PHONE NUMBER: ");
 while(Serial.available()==0){}          //INPUT PHONE NUMBER
 number = Serial.readString();
 delay(500);
  Serial.println ("Type s to send message or r to receive message");

}
void loop()
{
  if (Serial.available()>0)
   switch(Serial.read())
  {
    case 's':
      SendMessage();
      break;
    case 'r':
      RecieveMessage();
      break;
  }
 if (SIM900A.available()>0)
   Serial.write(SIM900A.read());
}
 void SendMessage()
{
  Serial.println ("Sending Message");
  SIM900A.println("AT+CMGF=1");
  delay(1000);
  Serial.println ("Set SMS Number");
  SIM900A.print("AT+CMGS=\""+number+"\"\r");   //send to input phone number
  delay(1000);
  Serial.print(number);
  delay(500);
  Serial.println ("Set SMS Content");
  SIM900A.print("Message from ArduinoGSMSIM900");
  delay(100);
  Serial.println ("Finish");
  SIM900A.println((char)26);
  delay(1000);
  Serial.println ("Message has been sent");
}
 void RecieveMessage()
{
  Serial.println ("SIM900A Membaca SMS");
  delay (1000);
  SIM900A.println("AT+CNMI=2,2,0,0,0");
  delay(1000);
  Serial.write ("Unread Message done");
}

请帮助我，在此先感谢！

Answer 1

如果你读过 SoftwareSerial Library documentation，你会注意到它说：

The library has the following known limitations:

Not all pins on the Mega and Mega 2560 support change interrupts, so only the following can be used for RX: 10, 11, 12, 13, 14, 15, 50, 51, 52, 53, A8 (62), A9 (63), A10 (64), A11 (65), A12 (66), A13 (67), A14 (68), A15 (69).

因此，请将 SoftwareSerial SIM900A(6,7); 上的线路更改为引脚 6 和 7 以外的线路。

Answer 2

好的，经过这么多研究我解决了我的问题。这是为那些和我有同样问题的人准备的，他们为一行简单的代码浪费了很多时间。当我 serial.readString() 输出将有一个白色 space 就像@hcheung 说的，所以为了摆脱那个白色 space 我使用 number.Trim()，它将准确读取字符串长度。

arduino GSM SIM900 的最终草图：

#include <SoftwareSerial.h>
SoftwareSerial SIM900A(10,11);
String number;
String message;
void setup()
{
  SIM900A.begin(9600);
  Serial.begin(9600);
  Serial.println ("SIM900A Ready");
  delay(100);
 Serial.print("Enter PHONE NUMBER: ");
 while(Serial.available()==0){}
 number = Serial.readString();
 delay(100);
 number.trim();
 delay(200);
 Serial.println(number.length());
 Serial.print("Enter MESSAGE: ");
 while(Serial.available()==0){}
 message = Serial.readString();
 delay(100);
  Serial.println ("Type s to send message or r to receive message");

}
void loop()
{
  if (Serial.available()>0)
   switch(Serial.read())
  {
    case 's':
      SendMessage();
      break;
    case 'r':
      RecieveMessage();
      break;
  }
 if (SIM900A.available()>0)
   Serial.write(SIM900A.read());
}
 void SendMessage()
{
  Serial.println ("Sending Message");
  SIM900A.println("AT+CMGF=1");
  delay(1000);
  Serial.println ("Set SMS Number");
  SIM900A.print("AT+CMGS=\""+number+"\"\r");
  delay(1000);
  Serial.print(number);
  delay(500);
  Serial.println ("Set SMS Content");
  SIM900A.print(message);
  delay(100);
  Serial.println ("Finish");
  SIM900A.println((char)26);
  delay(1000);
  Serial.println ("Message has been sent");
}
 void RecieveMessage()
{
  Serial.println ("SIM900A Membaca SMS");
  delay (1000);
  SIM900A.println("AT+CNMI=2,2,0,0,0");
  delay(1000);
  Serial.write ("Unread Message done");
}

为什么 Arduino mega 和 SIM900 不会发送消息如果我 input/read 到串行监视器，不同的 phone 数字？

Why does Arduino mega and SIM900 won't send message if I input/read to serial monitor, different phone numbers?

arduino

sms

gsm

sim900