How To Use ESP8266/NodeMCU using Arduino IDE
Nodemcu is not just a WiFi module, it also has a decent micro-controller in built. Nodemcu comes with 32-bit Tensilica Processor, Power-Saving Architecture, Compactness, High Durability. In this small tutorial, I will show you how easy it is to add Arduino Support.
Download Arduino IDE from https://www.arduino.cc/en/Main/Software
Install the ESP8266 Board Package
- Select the Preferences under File.
- Enter http://arduino.esp8266.com/stable/package_esp8266com_index.json into Additional Boards Manager URL’s field under preferences as shown below.
- Next, Select the Board manager under Tools.
- Next, use the Board manager to install the ESP8266 package.
- Now last step Restart the Arduino IDE and Select the specific Board. Go to Tools =>Board and select “Generic ESP8266 Module” Now you can use ESP8266 with Arduino IDE.
Test Example of DHT11 Temperature & Humidity sensor on NodeMCU using Arduino IDE
The DHT11 is chosen because it is lab calibrated, accurate and stable and its signal output is digital. Most important of all, it is relatively inexpensive for the given performance. Below is the pinout of the sensor.
Installing Libraries
- Click here to download the DHT sensor library.
- Unzip the .zip folder and you should get DHT-sensor-library-master folder
- Rename your folder from
DHT-sensor-library-masterto DHT - Move the DHT folder to your Arduino IDE installation libraries folder
- You also need to install the Adafruit Unified Sensor Driver Library.
- Unzip the .zip folder and you should get Adafruit_sensor-master folder
- Rename your folder from
Adafruit_sensor-masterto Adafruit_sensor - Move the DHT_sensor folder to your Arduino IDE installation libraries folder
- Finally, re-open your Arduino IDE
Copy the sketch below to your Arduino IDE. Replace the SSID and password with your own credentials.
// Including the ESP8266 WiFi library #include <ESP8266WiFi.h> #include "DHT.h" // Uncomment one of the lines below for whatever DHT sensor type you're using! #define DHTTYPE DHT11 // DHT 11 // Replace with your network details const char* ssid = "YOUR_NETWORK_NAME"; const char* password = "YOUR_NETWORK_PASSWORD"; // Web Server on port 80 WiFiServer server(80); // DHT Sensor const int DHTPin = 5; // Initialize DHT sensor. DHT dht(DHTPin, DHTTYPE); // Temporary variables static char celsiusTemp[7]; static char fahrenheitTemp[7]; static char humidityTemp[7]; // only runs once on boot void setup() { // Initializing serial port for debugging purposes Serial.begin(115200); delay(10); dht.begin(); // Connecting to WiFi network Serial.println(); Serial.print("Connecting to "); Serial.println(ssid); WiFi.begin(ssid, password); while (WiFi.status() != WL_CONNECTED) { delay(500); Serial.print("."); } Serial.println(""); Serial.println("WiFi connected"); // Starting the web server server.begin(); Serial.println("Web server running. Waiting for the ESP IP..."); delay(10000); // Printing the ESP IP address Serial.println(WiFi.localIP()); } // runs over and over again void loop() { // Listenning for new clients WiFiClient client = server.available(); if (client) { Serial.println("New client"); // bolean to locate when the http request ends boolean blank_line = true; while (client.connected()) { if (client.available()) { char c = client.read(); if (c == '\n' && blank_line) { // Sensor readings may also be up to 2 seconds 'old' (its a very slow sensor) float h = dht.readHumidity(); // Read temperature as Celsius (the default) float t = dht.readTemperature(); // Read temperature as Fahrenheit (isFahrenheit = true) float f = dht.readTemperature(true); // Check if any reads failed and exit early (to try again). if (isnan(h) || isnan(t) || isnan(f)) { Serial.println("Failed to read from DHT sensor!"); strcpy(celsiusTemp,"Failed"); strcpy(fahrenheitTemp, "Failed"); strcpy(humidityTemp, "Failed"); } else{ // Computes temperature values in Celsius + Fahrenheit and Humidity float hic = dht.computeHeatIndex(t, h, false); dtostrf(hic, 6, 2, celsiusTemp); float hif = dht.computeHeatIndex(f, h); dtostrf(hif, 6, 2, fahrenheitTemp); dtostrf(h, 6, 2, humidityTemp); // You can delete the following Serial.print's, it's just for debugging purposes Serial.print("Humidity: "); Serial.print(h); Serial.print(" %\t Temperature: "); Serial.print(t); Serial.print(" *C "); Serial.print(f); Serial.print(" *F\t Heat index: "); Serial.print(hic); Serial.print(" *C "); Serial.print(hif); Serial.print(" *F"); Serial.print("Humidity: "); Serial.print(h); Serial.print(" %\t Temperature: "); Serial.print(t); Serial.print(" *C "); Serial.print(f); Serial.print(" *F\t Heat index: "); Serial.print(hic); Serial.print(" *C "); Serial.print(hif); Serial.println(" *F"); } client.println("HTTP/1.1 200 OK"); client.println("Content-Type: text/html"); client.println("Connection: close"); client.println(); // your actual web page that displays temperature and humidity client.println("<!DOCTYPE HTML>"); client.println("<html>"); client.println("<head></head><body><h1>ESP8266 - Temperature and Humidity</h1><h3>Temperature in Celsius: "); client.println(celsiusTemp); client.println("*C</h3><h3>Temperature in Fahrenheit: "); client.println(fahrenheitTemp); client.println("*F</h3><h3>Humidity: "); client.println(humidityTemp); client.println("%</h3><h3>"); client.println("</body></html>"); break; } if (c == '\n') { // when starts reading a new line blank_line = true; } else if (c != '\r') { // when finds a character on the current line blank_line = false; } } } // closing the client connection delay(1); client.stop(); Serial.println("Client disconnected."); } }
Open the Arduino IDE serial monitor at a baud rate of 115200. After a few seconds your IP address should appear. Open any browser from a device that is connected to the same router that your ESP is. Then type the IP address and click Enter!, Now you can see temp and humd in browser.
Pin Diagram
- DHT 11 vcc => 5V pin Nodemcu
- DHT 11 GND => GND pin Nodemcu
- DHT 11 Data => D1 pin Nodemcu
