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Arnov Sharma
Published © MIT

Smart Light Conversion using ESP8266 and a Relay

A standard 18W light panel was converted into a smart light that can be controlled via a simple web app.

BeginnerFull instructions provided1 hour207

Things used in this project

Hardware components

NodeMCU ESP8266 Breakout Board
NodeMCU ESP8266 Breakout Board
×1
Relay Module (Generic)
×1

Software apps and online services

Fusion
Autodesk Fusion

Hand tools and fabrication machines

3D Printer (generic)
3D Printer (generic)

Story

Read more

Custom parts and enclosures

Holder

Base

lid

Schematics

SCH1

sch2

Code

code

C/C++
#include <ESP8266WiFi.h>

// Webserver Config
const char* ssid = "YOURSSID";
const char* password = "YOURPASS";

// Set web server port number to 80
WiFiServer server(80);

// Variable to store the HTTP request
String header;

// Auxiliar variables to store the current output state
String output1State = "off";


// Assign output variables to GPIO pins
const int output1 = 16; //D0


void setup() {
  Serial.begin(115200);
  // Initialize the output variables as outputs
  pinMode(output1, OUTPUT);

 
  // Set outputs to HIGH
  digitalWrite(output1, HIGH);

  
  // Connect to Wi-Fi network with SSID and password
  Serial.print("Connecting to ");
  Serial.println(ssid);
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  // Print local IP address and start web server
  Serial.println("");
  Serial.println("WiFi connected.");
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());
  server.begin();
}

void loop(){
  WiFiClient client = server.available();   // Listen for incoming clients

  if (client) {                             // If a new client connects,
    Serial.println("New Client.");          // print a message out in the serial port
    String currentLine = "";                // make a String to hold incoming data from the client
    while (client.connected()) {            // loop while the client's connected
      if (client.available()) {             // if there's bytes to read from the client,
        char c = client.read();             // read a byte, then
        Serial.write(c);                    // print it out the serial monitor
        header += c;
        if (c == '\n') {                    // if the byte is a newline character
          // if the current line is blank, you got two newline characters in a row.
          // that's the end of the client HTTP request, so send a response:
          if (currentLine.length() == 0) {
            // HTTP headers always start with a response code (e.g. HTTP/1.1 200 OK)
            // and a content-type so the client knows what's coming, then a blank line:
            client.println("HTTP/1.1 200 OK");
            client.println("Content-type:text/html");
            client.println("Connection: close");
            client.println();
            
            // turns the GPIOs on and off
            if (header.indexOf("GET /1/on") >= 0) {         //LOAD1
              Serial.println("LOAD1 on");
              output1State = "on";
              digitalWrite(output1, LOW);
            } else if (header.indexOf("GET /1/off") >= 0) {
              Serial.println("LOAD1 off");
              output1State = "off";
              digitalWrite(output1, HIGH);
            }
            
            
            // Display the HTML web page
            client.println("<!DOCTYPE html><html>");
            client.println("<head><meta name=\"viewport\" content=\"width=device-width, initial-scale=1\">");
            client.println("<link rel=\"icon\" href=\"data:,\">");
            client.println("<style>html { font-family: Helvetica; display: inline-block; margin: 0px auto; text-align: center;}");
            client.println(".button { background-color: #6a195b; border: none; color: white; padding: 16px 40px;");
            client.println("text-decoration: none; font-size: 30px; margin: 2px; cursor: pointer;}");
            client.println(".button2 {background-color: #a82890;}</style></head>");
            
            // Web Page Heading
            client.println("<body><h1>HOME AUTOMATION BASIC</h1>");
            
            // Display current state, and ON/OFF buttons for OUTPUT1 
            client.println("<p>LOAD1 - State " + output1State + "</p>");
           
            // If the output1State is off, it displays the ON button       
            if (output1State=="off") {
              client.println("<p><a href=\"/1/on\"><button class=\"button\">ON</button></a></p>");
            } else {
              client.println("<p><a href=\"/1/off\"><button class=\"button button2\">OFF</button></a></p>");
            } 

              
            client.println("</body></html>");
            
            // The HTTP response ends with another blank line
            client.println();
            // Break out of the while loop
            break;
          } else { // if you got a newline, then clear currentLine
            currentLine = "";
          }
        } else if (c != '\r') {  // if you got anything else but a carriage return character,
          currentLine += c;      // add it to the end of the currentLine
        }
      }
    }
    // Clear the header variable
    header = "";
    // Close the connection
    client.stop();
    Serial.println("Client disconnected.");
    Serial.println("");
  }
}

Credits

Arnov Sharma
310 projects • 311 followers
Just your average MAKER

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