Wi-Fi Modules

1. Definition

Wi-Fi Modules allow microcontrollers to connect to wireless networks for internet-based communication.
They are commonly used in IoT (Internet of Things) projects to send or receive data from web servers, cloud platforms, or mobile apps.

Examples: ESP8266, ESP32, NodeMCU, and ESP-01. Wi-Fi module example

2. Features

  • Provides wireless connectivity to devices.
  • Supports TCP/IP protocols for internet communication.
  • Can act as a Wi-Fi client (connect to a router) or Wi-Fi Access Point (AP).
  • Available as standalone microcontrollers (ESP32, ESP8266) or as modules controlled via AT commands.
  • Supports IoT platforms like Blynk, Firebase, MQTT, and Google Cloud.

3. Applications

  • Home automation (smart lights, fans, appliances).
  • IoT monitoring systems (temperature, air quality, security).
  • Data logging to the cloud or local server.
  • Remote control using mobile apps or web dashboards.
  • Robotics with wireless control.

4. How It Works

  • The microcontroller communicates with the Wi-Fi module via UART (TX/RX pins) or runs directly on the module (e.g., ESP8266, ESP32).
  • The module connects to a Wi-Fi router or creates its own hotspot.
  • Data is sent/received through HTTP, MQTT, or WebSocket protocols.

5. Circuit Example

Wi-Fi module circuit example

  • Connect VCC → 3.3V (some boards have regulators for 5V input).
  • GND → Ground.
  • TX ↔ RX with microcontroller (cross-connected).
  • EN/CH_PD pin → HIGH (3.3V) to enable the module.

6. Code Example (ESP8266 with Arduino IDE) 

#include <ESP8266WiFi.h>

const char* ssid = "YourWiFi";
const char* password = "YourPassword";

void setup() {
  Serial.begin(115200);
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("Connected to WiFi!");
}

void loop() {
  // Add IoT code here
}

7. Video Explanation

video coming soon