Sending Messages via SMS or Telegram Using an ESP32 PLC 14 with Integrated 4G

#define SECRET_PINNUMBER     ""
#define SECRET_APN           ""
#define SECRET_USERNAME      ""
#define SECRET_PASSWORD      ""

// Include the NB library
#include <NB.h>

// Uncomment to automatically configure the module baud rate
#define MAKE_AUTOBAUD 

#include "arduino_secrets.h" 

// PIN and APN details
const char PINNUMBER[] = SECRET_PINNUMBER;
const char APN[] = SECRET_APN;
const char USERNAME[] = SECRET_USERNAME;
const char PASSWORD[] = SECRET_PASSWORD;

// Initialize the library instance
NB nbAccess(true);
NB_SMS sms;

void setup() {
  Serial.begin(115200);
  while (!Serial);

  Serial.println("SMS Messages Sender");

  // Connection state
  bool connected = false;

  // Configure autobaud
#ifdef MAKE_AUTOBAUD
  if (nbAccess.autobaud()) {
    Serial.println("Autobaud completed successfully");
    nbAccess.shutdown();
  } else {
    Serial.println("Autobaud failed.");
    while (1);
  }
#endif

  // Connect to the network
  while (!connected) {
    if (nbAccess.begin(PINNUMBER, APN, USERNAME, PASSWORD) == NB_READY) {
      connected = true;
    } else {
      Serial.println("Not connected, retrying...");
      delay(1000);
    }
  }

  Serial.println("NB initialized");
}

void loop() {
  Serial.print("Enter a mobile number: ");
  char remoteNum[20];
  readSerial(remoteNum);

  Serial.print("Now, enter SMS content: ");
  char txtMsg[200];
  readSerial(txtMsg);

  sms.beginSMS(remoteNum);
  sms.print(txtMsg);
  sms.endSMS();
  Serial.println("Message sent!");
}

int readSerial(char result[]) {
  int i = 0;
  while (true) {
    while (Serial.available() > 0) {
      char inChar = Serial.read();
      if (inChar == '\n') {
        result[i] = '\0';
        return 0;
      }
      if (inChar != '\r') {
        result[i] = inChar;
        i++;
      }
    }
  }
}

#define SECRET_PINNUMBER     ""
#define SECRET_APN           ""
#define SECRET_USERNAME      ""
#define SECRET_PASSWORD      ""

#define SECRET_USER          ""

// Include the NB library
#include <NB.h>

// Uncomment to automatically configure the module baud rate
#define MAKE_AUTOBAUD 

#include "arduino_secrets.h"

// PIN and APN details
const char PINNUMBER[] = SECRET_PINNUMBER;
const char APN[] = SECRET_APN;
const char USERNAME[] = SECRET_USERNAME;
const char PASSWORD[] = SECRET_PASSWORD;

// Telegram USER (without '@')
const char USER[] = SECRET_USER;

// Initialize library instances
NBClient client;
GPRS gprs;
NB nbAccess(true);

// Server details
char server[] = "api.callmebot.com";
int port = 80;

void setup() {
  Serial.begin(115200);
  while (!Serial);

  Serial.println("Call Me Bot Messages Sender");

  // Connection state
  bool connected = false;

#ifdef MAKE_AUTOBAUD
  if (nbAccess.autobaud()) {
    Serial.println("Autobaud completed successfully");
    nbAccess.shutdown();
  } else {
    Serial.println("Autobaud could not configure the module correctly. Trying again...");
    if (nbAccess.autobaud()) {
      Serial.println("Autobaud completed successfully");
      nbAccess.shutdown();
    } else {
      Serial.println("Autobaud could not configure the module correctly. Blocking...");
      while(1);
    }
  }
#endif

  // Start NB module and attach GPRS
  while (!connected) {
    if ((nbAccess.begin(PINNUMBER, APN, USERNAME, PASSWORD) == NB_READY) && (gprs.attachGPRS() == GPRS_READY)) {
      connected = true;
    } else {
      Serial.println("Not connected, retrying...");
      delay(1000);
    }
  }

  Serial.println("NB and GPRS initialized");
}

void loop() {
  // Prompt user for a message
  Serial.print("Enter the message to send: ");
  char txtMsg[200];
  readSerial(txtMsg);

  // Encode the message for URL (replace spaces with '%20')
  String msgPayload = txtMsg;
  msgPayload.replace(" ", "%20");

  // Construct the GET request path
  char path[500];
  sprintf(path, "/text.php?source=web&user=@%s&text=%s", USER, msgPayload.c_str());

  Serial.println("Connecting to Call Me Bot...");

  if (client.connect(server, port)) {
    Serial.println("Connected to Call Me Bot server");

    // Make an HTTP GET request
    client.print("GET ");
    client.print(path);
    client.println(" HTTP/1.1");
    client.print("Host: ");
    client.println(server);
    client.println("Connection: close");
    client.println();
  } else {
    Serial.println("Connection failed");
    return;
  }

  // Wait for the server to respond, read response
  while (client.connected()) {
    while (client.available()) {
      char c = client.read();
      Serial.print(c);
    }
  }

  Serial.println();
  Serial.println("Disconnecting from server.");
  client.stop();
}

int readSerial(char result[]) {
  int i = 0;
  while (1) {
    while (Serial.available() > 0) {
      char inChar = (char)Serial.read();
      if (inChar == '\n') {
        result[i] = '\0';
        Serial.flush();
        return 0;
      }
      if (inChar != '\r') {
        result[i] = inChar;
        i++;
      }
    }
  }
}