Blynk_App.ino

// TTGO T-Call pin definitions
#define MODEM_RST            5
#define MODEM_PWKEY          4
#define MODEM_POWER_ON       23
#define MODEM_TX             27
#define MODEM_RX             26
#define I2C_SDA              21
#define I2C_SCL              22

#define BLYNK_PRINT Serial    
#define BLYNK_HEARTBEAT 30
#define TINY_GSM_MODEM_SIM800

#include <TinyGsmClient.h>
#include <BlynkSimpleSIM800.h>

#include <Wire.h>
// #include <TinyGsmClient.h>
#include "utilities.h"

// Set serial for debug console (to the Serial Monitor, default speed 115200)
#define SerialMon Serial

// Hardware Serial on Mega, Leonardo, Micro
#define SerialAT Serial1


const char apn[]  = "YourAPN";
const char user[] = "";
const char pass[] = "";

// You should get Auth Token in the Blynk App.
// Go to the Project Settings (nut icon).
const char auth[] = "Auth Token";

TinyGsm modem(SerialAT);

void setup()
{
  // Set console baud rate
  SerialMon.begin(115200);
  delay(10);

  // Keep power when running from battery
  Wire.begin(I2C_SDA, I2C_SCL);
  bool   isOk = setPowerBoostKeepOn(1);
  SerialMon.println(String("IP5306 KeepOn ") + (isOk ? "OK" : "FAIL"));

  // Set-up modem reset, enable, power pins
  pinMode(MODEM_PWKEY, OUTPUT);
  pinMode(MODEM_RST, OUTPUT);
  pinMode(MODEM_POWER_ON, OUTPUT);

  digitalWrite(MODEM_PWKEY, LOW);
  digitalWrite(MODEM_RST, HIGH);
  digitalWrite(MODEM_POWER_ON, HIGH);

  // Set GSM module baud rate and UART pins
  SerialAT.begin(115200, SERIAL_8N1, MODEM_RX, MODEM_TX);
  delay(3000);

  // Restart takes quite some time
  // To skip it, call init() instead of restart()
  SerialMon.println("Initializing modem...");
  modem.restart();

  String modemInfo = modem.getModemInfo();
  SerialMon.print("Modem: ");
  SerialMon.println(modemInfo);

  // Unlock your SIM card with a PIN
  //modem.simUnlock("1234");

   SerialMon.print("Waiting for network...");
  if (!modem.waitForNetwork(240000L)) {
    SerialMon.println(" fail");
    delay(10000);
    return;
  }
  SerialMon.println(" OK");

  if (modem.isNetworkConnected()) {
    SerialMon.println("Network connected");
  }

  SerialMon.print(F("Connecting to APN: "));
  SerialMon.print(apn);
  if (!modem.gprsConnect(apn, user, pass)) {
    SerialMon.println(" fail");
    delay(10000);
    return;
  }
  SerialMon.println(" OK");

  Blynk.begin(auth, modem, apn, user, pass);
}

void loop()
{
  Blynk.run();
}