I've been trying to create SMS alarm using Twilio, Firebase and Arduino IDE. Using sensors I am measuring the temperature. If the temperature is higher than a specified value (ESP reads that value from Firebase Realtime Database), a SMS should be sent using twilio. I am also storing the measures in Firebase Realtime Database. The code worked well, until I tried to add the part where it also pushed measurements (temperatures) to Firebase Realtime Database. It even prints in serial that it is connecting to Twilio api, however, I never receive the message.

Here's my code:

 * Twilio SMS and MMS on ESP8266 Example.
 #include "FirebaseArduino.h"
#include "OneWire.h"
#include "DallasTemperature.h"
#include <ESP8266WiFi.h>
#include <WiFiClientSecure.h>
#include <ESP8266WebServer.h>
#include <sstream> 
#include <iostream> 
#include "twilio.hpp"

// Use software serial for debugging?

// Print debug messages over serial?
#define USE_SERIAL 1

// Your network SSID and password
const char* ssid="SSID";
const char* password = "PASSWORD";

// Find the api.twilio.com SHA1 fingerprint, this one was valid as 
// of July 2020. This will change, please see 
// https://www.twilio.com/docs/sms/tutorials/how-to-send-sms-messages-esp8266-cpp
// to see how to update the fingerprint.
const char fingerprint[] = "BC B0 1A 32 80 5D E6 E4 A2 29 66 2B 08 C8 E0 4C 45 29 3F D0";

// Twilio account specific details, from https://twilio.com/console
// Please see the article: 
// https://www.twilio.com/docs/guides/receive-and-reply-sms-and-mms-messages-esp8266-c-and-ngrok

// If this device is deployed in the field you should only deploy a revocable
// key. This code is only suitable for prototyping or if you retain physical
// control of the installation.
const char* account_sid = "SID";
const char* auth_token = "TOKEN";

// Details for the SMS we'll send with Twilio.  Should be a number you own 
// (check the console, link above).
String to_number    = "+55555";
String from_number = "+66666";
String message_body    = "Hello from Twilio and the ESP8266!";

// The 'authorized number' to text the ESP8266 for our example
String master_number    = "+55555";

// Optional - a url to an image.  See 'MediaUrl' here: 
// https://www.twilio.com/docs/api/rest/sending-messages
String media_url = "";

// Global twilio objects
Twilio *twilio;
ESP8266WebServer twilio_server(8000);

//  Optional software serial debugging
#include <SoftwareSerial.h>
// You'll need to set pin numbers to match your setup if you
// do use Software Serial
extern SoftwareSerial swSer(14, 4, false, 256);
#define swSer Serial

String b;
int c;
#define FIREBASE_HOST "firebaseio.com"
#define FIREBASE_AUTH ""

#define ONE_WIRE_BUS 4 
// Setup a oneWire instance to communicate with any OneWire devices  
// (not just Maxim/Dallas temperature ICs) 
OneWire oneWire(ONE_WIRE_BUS); 
// Pass our oneWire reference to Dallas Temperature. 
DallasTemperature sensors(&oneWire);

float temp1 = 0;

 * Setup function for ESP8266 Twilio Example.
 * Here we connect to a friendly wireless network, set the time, instantiate 
 * our twilio object, optionally set up software serial, then send a SMS 
 * or MMS message.
void setup() {
        WiFi.begin(ssid, password);
        twilio = new Twilio(account_sid, auth_token, fingerprint);

        #if USE_SERIAL == 1
        while (WiFi.status() != WL_CONNECTED) {
        swSer.println("Connected to WiFi, IP address: ");
        while (WiFi.status() != WL_CONNECTED) delay(1000);

        // Response will be filled with connection info and Twilio API responses
        // from this initial SMS send.


        // Use LED_BUILTIN to find the LED pin and set the GPIO to output
        pinMode(LED_BUILTIN, OUTPUT);

         Firebase.begin(FIREBASE_HOST, FIREBASE_AUTH); 


 *  In our main loop, we listen for connections from Twilio in handleClient().
void loop() {
  b = Firebase.getString("002/alarm");
  c = b.toInt();

   temp1 = sensors.getTempCByIndex(0);
   StaticJsonBuffer<256> jsonBuffer;
JsonObject& timeStampObject = jsonBuffer.createObject();
timeStampObject[".sv"] = "timestamp";

JsonObject& root = jsonBuffer.createObject();
JsonArray& timestamp = root.createNestedArray("timestamp");
JsonArray& temperature = root.createNestedArray("temperature");

Firebase.push("Sensors/001", root);
   if (temp1 > c) {
        String response;
        bool success = twilio->send_message(


Thanks in advance!

  • 1
    reduce your code to the minimum code that still exhibits the problem ... remove the firebase and the temperature sonsor code ... send only a fixed text SMS
    – jsotola
    Aug 23 '20 at 14:54
  • Hi, thanks for your reply! This is the minimum code. If I remove the part in the loop where it pushes the values to Firebase and it only sends a fixed SMS, when the value (temperature) is too high then the SMS gets send. However, I would also need it to push the values to Firebase. Is it possible that NodeMCU Amica V2 is not powerful enough to do that all in one loop?
    – Nina
    Aug 25 '20 at 16:49

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