GSMCode.ino

/*
  Rui Santos
  Complete project details at https://RandomNerdTutorials.com/esp32-cloud-mqtt-broker-sim800l/
  
  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files.
  
  The above copyright notice and this permission notice shall be included in all
  copies or substantial portions of the Software.
*/

// Select your modem:
#define TINY_GSM_MODEM_SIM800 // Modem is SIM800L

// Set serial for debug console (to the Serial Monitor, default speed 115200)
#define SerialMon Serial
// Set serial for AT commands
#define SerialAT Serial1

// Define the serial console for debug prints, if needed
#define TINY_GSM_DEBUG SerialMon

// set GSM PIN, if any
#define GSM_PIN ""

// Your GPRS credentials, if any
const char apn[] = "internet.ng.airtel.com"; // APN (example: internet.vodafone.pt) use https://wiki.apnchanger.org
const char gprsUser[] = "";
const char gprsPass[] = "";

// SIM card PIN (leave empty, if not defined)
const char simPIN[] = "";

// MQTT details
const char *broker = "broker.hivemq.com"; // Public IP address or domain name
const char *mqttUsername = "Changeover1"; // MQTT username
const char *mqttPassword = "frankyboo";   // MQTT password

const char *topicOutput1 = "frankyboo/Changeover1";
//const char *topicOutput2 = "esp/output2";
const char *topicTemperature = "frankyboo/temperature";

// Define the serial console for debug prints, if needed
//#define DUMP_AT_COMMANDS

#include <Wire.h>
#include <TinyGsmClient.h>

#ifdef DUMP_AT_COMMANDS
#include <StreamDebugger.h>
StreamDebugger debugger(SerialAT, SerialMon);
TinyGsm modem(debugger);
#else
TinyGsm modem(SerialAT);
#endif

#include <PubSubClient.h>

TinyGsmClient client(modem);
PubSubClient mqtt(client);

// TTGO T-Call pins
#define MODEM_RST 7
//#define MODEM_PWKEY 4
//#define MODEM_POWER_ON 23
#define MODEM_TX 9
#define MODEM_RX 8

#define OUTPUT_1 2
#define OUTPUT_2 15

uint32_t lastReconnectAttempt = 0;

float temperature = 0;
float humidity = 0;
long lastMsg = 0;

void mqttCallback(char *topic, byte *message, unsigned int len)
{
  Serial.print("Message arrived on topic: ");
  Serial.print(topic);
  Serial.print(". Message: ");
  String messageTemp;

  for (int i = 0; i < len; i++)
  {
    Serial.print((char)message[i]);
    messageTemp += (char)message[i];
  }
  Serial.println();

  // Feel free to add more if statements to control more GPIOs with MQTT

  // If a message is received on the topic esp/output1, you check if the message is either "true" or "false".
  // Changes the output state according to the message
  if (String(topic) == "frankyboo/Changeover1")
  {
    Serial.print("Changing output to ");
    if (messageTemp == "true")
    {
      Serial.println("true");
      digitalWrite(OUTPUT_1, HIGH);
    }
    else if (messageTemp == "false")
    {
      Serial.println("false");
      digitalWrite(OUTPUT_1, LOW);
    }
  }
}

boolean mqttConnect()
{
  SerialMon.print("Connecting to ");
  SerialMon.print(broker);

  // Connect to MQTT Broker without username and password
  //boolean status = mqtt.connect("GsmClientN");

  // Or, if you want to authenticate MQTT:
  boolean status = mqtt.connect("GsmClientN", mqttUsername, mqttPassword);

  if (status == false)
  {
    SerialMon.println(" fail");
    ESP.restart();
    return false;
  }
  SerialMon.println(" success");
  mqtt.subscribe(topicOutput1);
  mqtt.subscribe(topicOutput2);

  return mqtt.connected();
}

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

  // Set 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);

  // pinMode(OUTPUT_1, OUTPUT);
  // pinMode(OUTPUT_2, OUTPUT);

  SerialMon.println("Wait...");

  // Set GSM module baud rate and UART pins
  SerialAT.begin(115200, SERIAL_8N1, MODEM_RX, MODEM_TX);
  delay(6000);

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

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

  // Unlock your SIM card with a PIN if needed
  if (GSM_PIN && modem.getSimStatus() != 3)
  {
    modem.simUnlock(GSM_PIN);
  }

  SerialMon.print("Connecting to APN: ");
  SerialMon.print(apn);
  if (!modem.gprsConnect(apn, gprsUser, gprsPass))
  {
    SerialMon.println(" fail");
    ESP.restart();
  }
  else
  {
    SerialMon.println(" OK");
  }

  if (modem.isGprsConnected())
  {
    SerialMon.println("GPRS connected");
  }

  // MQTT Broker setup
  mqtt.setServer(broker, 1883);
  mqtt.setCallback(mqttCallback);
}

void loop()
{
  if (!mqtt.connected())
  {
    SerialMon.println("=== MQTT NOT CONNECTED ===");
    // Reconnect every 10 seconds
    uint32_t t = millis();
    if (t - lastReconnectAttempt > 10000L)
    {
      lastReconnectAttempt = t;
      if (mqttConnect())
      {
        lastReconnectAttempt = 0;
      }
    }
    delay(100);
    return;
  }

  long now = millis();
  if (now - lastMsg > 30000)
  {
    lastMsg = now;

    // Convert the value to a char array
    char humString[8];
    dtostrf(22, 1, 2, humString);
    Serial.print("Humidity: ");
    Serial.println(humString);
    mqtt.publish(topicHumidity, humString);
  }

  mqtt.loop();
}
{
  "mode" : "full", "isActive" : false
}