[arduino code examples for B2]-12 send Short Message (SMS) to mobile phone by SIM7600

Code:
/*

 * Made by KinCony IoT: https://www.kincony.com

 *

 * Send one SMS through SIM7600 using AT commands.

 * SIM7600 RXD -> ESP32 GPIO16 (TX)

 * SIM7600 TXD -> ESP32 GPIO15 (RX)

 */



#include <Arduino.h>



HardwareSerial modem(2);



constexpr int MODEM_RX = 15;

constexpr int MODEM_TX = 16;

constexpr uint32_t MODEM_BAUD = 115200;



const char PHONE_NUMBER[] = "+8615381188302";

const char SMS_TEXT[] = "kincony";



// Read modem responses and mirror them to the USB serial port.

bool waitFor(const char *expected, uint32_t timeoutMs) {

  String response;

  uint32_t start = millis();



  while (millis() - start < timeoutMs) {

    while (modem.available()) {

      char c = modem.read();

      Serial.write(c);

      response += c;



      if (response.indexOf(expected) >= 0) {

        return true;

      }



      if (response.indexOf("ERROR") >= 0) {

        return false;

      }

    }

    delay(1);

  }



  Serial.println("\n[Timeout]");

  return false;

}



bool sendAT(const String &command,

            const char *expected = "OK",

            uint32_t timeoutMs = 3000) {

  while (modem.available()) {

    Serial.write(modem.read());

  }



  Serial.print("\n>> ");

  Serial.println(command);



  modem.print(command);

  modem.print('\r');



  return waitFor(expected, timeoutMs);

}



void setup() {

  Serial.begin(115200);

  modem.begin(MODEM_BAUD, SERIAL_8N1, MODEM_RX, MODEM_TX);



  Serial.println("\nWaiting for SIM7600...");



  // Allow time for module startup and network registration.

  delay(15000);



  bool modemReady = false;

  for (int i = 0; i < 10; i++) {

    if (sendAT("AT")) {

      modemReady = true;

      break;

    }

    delay(1000);

  }



  if (!modemReady) {

    Serial.println("No modem response. Check power, baud rate and UART pins.");

    return;

  }



  if (!sendAT("ATE0")) return;

  if (!sendAT("AT+CPIN?", "+CPIN: READY")) {

    Serial.println("SIM card is not ready.");

    return;

  }



  // Print signal strength and registration status for diagnosis.

  sendAT("AT+CSQ");

  sendAT("AT+CREG?");

  sendAT("AT+CEREG?");



  // Configure SMS text mode and GSM character set.

  if (!sendAT("AT+CMGF=1")) return;

  if (!sendAT("AT+CSCS=\"GSM\"")) return;



  String command = String("AT+CMGS=\"") + PHONE_NUMBER + "\"";



  if (!sendAT(command, ">", 10000)) {

    Serial.println("SMS input prompt was not received.");

    return;

  }



  modem.print(SMS_TEXT);

  modem.write((uint8_t)0x1A);  // Ctrl+Z submits the SMS.



  // Do not retry automatically: this avoids duplicate messages.

  if (waitFor("+CMGS:", 120000)) {

    Serial.println("\nSMS submitted successfully.");

  } else {

    Serial.println("\nSMS failed or result is unknown. Check modem output.");

  }

}



void loop() {

  // UART bridge for manual AT-command debugging.

  while (modem.available()) {

    Serial.write(modem.read());

  }



  while (Serial.available()) {

    modem.write(Serial.read());

  }

}