Tom Battista
Published © CC BY

Control Stuff From The Internet: Create a WiFi Switch

Learn about relays and WiFi and how to create an internet switch using the Wemos D1 Mini and the relay shield.

BeginnerFull instructions provided2 hours4,936
Control Stuff From The Internet: Create a WiFi Switch

Things used in this project

Hardware components

Wemos D1 Mini
Espressif Wemos D1 Mini
×1
Wemos Relay Shield
×1
USB-A to Micro-USB Cable
USB-A to Micro-USB Cable
×1

Software apps and online services

Arduino IDE
Arduino IDE

Hand tools and fabrication machines

Soldering iron (generic)
Soldering iron (generic)

Story

Read more

Code

Innovative Tom Demo Relay Project

Arduino
In the video I walk though each step of code. I have also commented throughout.
//This example will use a static IP to control the switching of a relay. Over LAN using a web browser. 
//A lot of this code have been resued from the example on the ESP8266 Learning Webpage below. 
//http://www.esp8266learning.com/wemos-webserver-example.php

//CODE START 
//1
#include <ESP8266WiFi.h>

// Below you will need to use your own WIFI informaiton.
//2
const char* ssid = "THE WIFI Guest"; //WIFI Name, WeMo will only connect to a 2.4GHz network.
const char* password = "52269738"; //WIFI Password

//defining the pin and setting up the "server"
//3
int relayPin = D1; // The Shield uses pin 1 for the relay
WiFiServer server(80);
IPAddress ip(10, 0, 0, 99); // where xx is the desired IP Address
IPAddress gateway(10, 0, 0, 1); // set gateway to match your network
IPAddress subnet(255, 255, 255, 0); // set subnet mask to match your network


// void setup is where we initialize variables, pin modes, start using libraries, etc. 
//The setup function will only run once, after each powerup or reset of the wemos board.
//4
void setup() {
  Serial.begin(115200);
  delay(10);
 

  pinMode(relayPin, OUTPUT);
  digitalWrite(relayPin, LOW);
 
  Serial.print(F("Setting static ip to : "));
  Serial.println(ip);
  
  // Connect to WiFi network
  //5
  Serial.println();
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);
  WiFi.config(ip, gateway, subnet); 
  WiFi.begin(ssid, password);
  //Trying to connect it will display dots
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("");
  Serial.println("WiFi connected");
 
  // Start the server
  server.begin();
  Serial.println("Server started");
 
  // Print the IP address
  Serial.print("Use this URL : ");
  Serial.print("http://");
  Serial.print(WiFi.localIP());
  Serial.println("/"); 
}

//void loop is where you put all your code. it is a funtion that returns nothing and will repeat over and over again
//6
void loop() {
  // Check if a client has connected
  WiFiClient client = server.available();
  if (!client) {
    return;
  }
 
  // Wait until the client sends some data
  Serial.println("new client");
  while(!client.available()){
    delay(1);
  }
 
  // Read the first line of the request
  String request = client.readStringUntil('\r');
  Serial.println(request);
  client.flush();
 
  //Match the request, checking to see what the currect state is
  int value = LOW;
  if (request.indexOf("/relay=ON") != -1) {
    digitalWrite(relayPin, HIGH);
    value = HIGH;
  } 
  if (request.indexOf("/relay=OFF") != -1){
    digitalWrite(relayPin, LOW);
    value = LOW;
  }
  // Return the response, build the html page
  //7
  client.println("HTTP/1.1 200 OK");
  client.println("Content-Type: text/html");
  client.println(""); //  do not forget this one
  client.println("<!DOCTYPE HTML>");
  client.println("<html>");
 
  client.print("Relay is now: ");
 
  if(value == HIGH) {
    client.print("Engaged (ON)");  
  } else {
    client.print("Disengaged (OFF)");
  }
  client.println("<br><br><br>");
  client.println("<a href=\"/relay=ON\">Click here to engage (Turn ON) the relay.</a> <br><br><br>");
  client.println("<a href=\"/relay=OFF\">Click here to disengage (Turn OFF) the relay.</a><br>");
  client.println("</html>");
 
  delay(1);
  Serial.println("Client disconnected");
  Serial.println("");
 
}//END

Credits

Tom Battista
3 projects • 11 followers
I love building things and documenting the process. By doing so I hope it empowers you to get out and build something of your own.
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