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// Created by Ty Tower in June 11 2015
// Modified by S.Parada for ACROBOTIC Industries Oct 2015
// Based on DHTtester.ino By Adafruit
// Public domain
// This code takes readings from a DHT22 sensor and posts them via
// For this exercise you will need to set up a free Ubidots account
#include <DHT.h>
#include <ESP8266WiFi.h>
#define errorPin 16
#define DHTPIN D2
#define DHTTYPE DHT22
// Instantiates and initializes the dht object
// Define and initialize constants and variables that we'll use later in the code
const int sleep_time = 20; // Time to sleep (in seconds) between posts to Ubidots
WiFiClient client;
// After creating an account on Ubidots, you'll be able to setup variables where you
// will store the data. In order to post the measurements to the Ubidots variables,
// we need their "IDs", which are given on the website
String variable_id1 = "variableId_temperature";
String variable_id2 = "variableId_humidity";
// In addition, we'll need the API token, which is what prevents other users
// Ubidots to publish their data to one of your variables
String token = "access_token";
// We'll also initialize the values for our Wi-Fi network
const char* ssid = "YOUR_SSID";
const char* password = "YOUR_PASSWORD";
// Function Prototypes
void ubiSave_value(String, String);
// The setup function is executed once by the ESP8266 when it's powered up or reset
void setup()
pinMode(errorPin, OUTPUT); // sets pin as an output to drive an LED for status indication
// The following loop flashes the LED four times to indicate we're inside the setup function
for (int i=0;i<4; i++)
digitalWrite(errorPin ,HIGH);
digitalWrite(errorPin ,LOW);
// Initialize Serial (USB) communication, which will be used for sending debugging messages
// to the computer
// Start the communication with the DHT sensor by callibg the begin method of the dht object
// Manual delay while the communication with the sensor starts
// Debug messsages to indicate we're about to connect to the network
Serial.print("Connecting to ");
// Use the scanNetworks method inside the Wi-Fi class to scan for any available Wi-Fi networks
// nearby. If none are found, go to sleep
int n = WiFi.scanNetworks();
Serial.println("scan done");
if (n == 0)
Serial.println("no networks found");
Serial.println("Going into sleep");
// ESP.deepSleep(sleep_time * 1000000);
// If networks are found, attempt to connect to our Wi-Fi network
WiFi.begin(ssid, password);
// While the connection is not established, IDLE inside this while loop
while (WiFi.status() != WL_CONNECTED)
// Once the connection to our Wi-Fi netowrk is successful, print some debug messages
Serial.println("Wi-Fi connected");
// Main code
void loop()
// Read the current temperature and humidity measured by the sensor
float temp = dht.readTemperature(true);
float hum = dht.readHumidity();
// Call our user-defined function ubiSave_value (defined below), and pass it both the
// measurements as well as the corresponding Ubidots variable IDs
ubiSave_value(String(variable_id1), String(temp));
ubiSave_value(String(variable_id2), String(hum));
// Send some debug messages over USB
Serial.println("Ubidots data");
Serial.println("temperature: "+String(temp));
Serial.println("humidity: "+String(hum));
Serial.println(" Going to Sleep for a while !" );
// deepSleep time is defined in microseconds. Multiply seconds by 1e6
//ESP.deepSleep(sleep_time * 1000000);//one or other
// Wait a few seconds before publishing additional data to avoid saturating the system
// User-defined functions
// We encapsulate the grunt work for publishing temperature and humidty values to Ubidots
// inside the function ubiSave_value
void ubiSave_value(String variable_id, String value)
// Prepare the value that we're to send to Ubidots and get the length of the entire string
// that's being sent
String var = "{\"value\": " + value +"}"; // We'll pass the data in JSON format
String length = String(var.length());
// If we get a proper connection to the Ubidots API
if (client.connect("", 80))
Serial.println("Connected to Ubidots...");
// Construct the POST request that we'd like to issue
client.println("POST /api/v1.6/variables/"+variable_id+"/values HTTP/1.1");
// We also use the Serial terminal to show how the POST request looks like
Serial.println("POST /api/v1.6/variables/"+variable_id+"/values HTTP/1.1");
// Specify the contect type so it matches the format of the data (JSON)
client.println("Content-Type: application/json");
Serial.println("Content-Type: application/json");
// Specify the content length
client.println("Content-Length: "+ length);
Serial.println("Content-Length: "+ length);
// Use our own API token so that we can actually publish the data
client.println("X-Auth-Token: "+ token);
Serial.println("X-Auth-Token: "+ token);
// Specify the host
// Send the actual data
// If we can't establish a connection to the server:
Serial.println("Ubidots connection failed...");
// If our connection to Ubidots is healthy, read the response from Ubidots
// and print it to our Serial Monitor for debugging!
while (client.available())
char c =;
// Done with this iteration, close the connection.
if (client.connected())
Serial.println("Disconnecting from Ubidots...");