Combining SMS and Blynk

Need Help With My Project
1

Hi all! My hardware is Arduino Uno R3 and GSM shield based on SIM900 by keyestudio.
My goal is minimising payment for internet connection on GSM shield side. What I am trying to do in that case is: turn ON and OFF internet connection by SMS. (So, I send SMS - ON and after that blynk connect to server and I can manage it from the app. When SMS is OFF - shield disconnect blynk (or GPRS connection at all) )
So, the question is:

  1. Blynk.disconnect() - this method minimise gprs traffic or I have to turn off internet by AT-command ( AT+SAPBR=0,1)?
  2. How rightly turn back on blynk after receiving proper SMS?
    Maybe there is any simple way for achieving this goal?
    Thanks!
This is my code:
#define BLYNK_PRINT Serial
#define TINY_GSM_MODEM_SIM900
#include <GPRSk_Shield_Arduino.h>
#define pinBOOT 9  // нога BOOT или K на модеме M590, на SIM900 это 9
#include <TinyGsmClient.h>
#include <BlynkSimpleSIM800.h>
#include <DHT.h>
#define DHTPIN 5
#define DHTTYPE DHT11 
DHT dht(DHTPIN, DHTTYPE);
BlynkTimer timer;
#include <SoftwareSerial.h>
SoftwareSerial SerialAT(3,2); // RX, TX
SoftwareSerial mySerial(3,2);
GPRSk gprs(mySerial);
TinyGsm modem(SerialAT);
// Ваш токен
char auth[] = "0d0e0b22eee549**********************";
char apn[]  = "internet";
char user[] = "";
char pass[] = "";
//Method for DHT11
void sendSensor()
{
  float h = dht.readHumidity();
  float t = dht.readTemperature(); // or dht.readTemperature(true) for Fahrenheit

  if (isnan(h) || isnan(t)) {
    Serial.println("Failed to read from DHT sensor!");
    return;
  }
  // You can send any value at any time.
  // Please don't send more that 10 values per second.
  Blynk.virtualWrite(V2, h);
  Blynk.virtualWrite(V4, t);
}

void setup()
{
  ///////NOW CONFIGURING BLYNK AND GSM MODULE
  delay(3000);
  gprs.powerOn();
  Serial.begin(9600);
  delay(10);
  // Set GSM module baud rate 
  SerialAT.begin(9600);
  delay(3000);
  // Restart takes quite some time
  // To skip it, call init() instead of restart()
  Serial.println("Initializing modem...");
  modem.restart();
  delay(5000);
  // Unlock your SIM card with a PIN
  //modem.simUnlock("1234");
  Blynk.begin(auth, modem, apn, user, pass);
  dht.begin();
  timer.setInterval(1000L, sendSensor);
  ////////////////////NOW CONFIGURING RECEIVE/RESPONSE SMS MESSAGES
  mySerial.print("AT+CMGF=1\r");
  delay(300);
  mySerial.print("AT+IFC=1, 1\r");
  delay(300);
  mySerial.print("AT+CPBS=\"SM\"\r");
  delay(300);
  mySerial.print("AT+CNMI=1,2,2,1,0\r");
  delay(500);
}

void loop()
{
  //////This code handle SMS
  if (!gprsSerial.available())
    return;

  char currSymb = gprsSerial.read();
  if ('\r' == currSymb) {
    if (isStringMessage) {
      ////If we have sms like "InternetOn", I want to run blynk
      if (!currStr.compareTo("InternetOn")) {
      ///WILL THIS WORK AFTER RECEIVING SMS?
       Blynk.run();
       timer.run();
       Blynk.connect();
       ////////////////////////////////////////
        delay(5000);
        mySerial.println("AT + CMGS = \"+7967-------\"");
        delay(1000);
        gprsSerial.print("Internet turned on!");
        delay(100);
        gprsSerial.println((char)26);
        delay(1000);
        gprsSerial.println("\r");
        delay(100);
      }
      ////If we have sms like "InternetOff", I want to stop internet connection (or stop blynk)
        else if (!currStr.compareTo("InternetOff")) {
        Blynk.disconnect()
        /////////WILL IT WORK???
        ///////All of this is for minimising payment for internet
        ///maybe it is better to disconnect GPRS at all using this command?
        ////AT+SAPBR=0,1
        //
      }else {
      if (currStr.startsWith("+CMT")) {
        //если текущая строка начинается с "+CMT",
        //то следующая строка является сообщением
        isStringMessage = true;
      }
    }
    currStr = "";
  } else if ('\n' != currSymb) {
    currStr += String(currSymb);
  }
}
2

Yes, Blynk can be disabled (and thus no internet traffic) or enabled via connection management commands, but how entirely depends on the methods used.

For example you could use a button in the App to disable Blynk… but obviously not do so to enable it (since there is no link anymore) but as long as you ensure your sketch keeps running when not connected to Blynk, via Blynk.config() and other check loops and so one then you could have a timer or other process running on the sketch that would re-connect to Blynk as required.

3

Thanks!!!