Arduino Easy Smart Home Series: WiFi-Controlled WS2812 LED Strip with LDR Sensor

Bring your room to life with smart, interactive lighting! 🌈💡 This project uses a WS2812 RGB LED strip controlled over WiFi and automatically adjusts brightness based on ambient light using an LDR sensor. Perfect for home automation, mood lighting, or dynamic decorations. Control it from anywhere in your WiFi network!

Introduction
Required Hardware
Arduino IDE Setup
Wiring the Components
Arduino Code
How It Works
Testing Your Project
Advanced Modifications
Common Issues and Troubleshooting
Learning Insights
Conclusion

1. Introduction

This WiFi-controlled WS2812 LED strip project combines remote control and ambient light sensing. Using an ESP8266 or ESP32, you can turn your LED strip on/off, change colors, or run patterns via a web browser. The LDR sensor automatically dims or brightens the LEDs based on room lighting, creating a smart home-friendly lighting system that saves energy and looks amazing.

2. Required Hardware

ESP8266 (NodeMCU) or ESP32 (Approx. ₹400)
WS2812 (NeoPixel) LED strip, 8–30 LEDs (Approx. ₹300)
LDR Light Sensor (Approx. ₹5)
10kΩ Resistor for LDR (Approx. ₹10)
Capacitor 1000µF, 6.3V+ for LED strip (Approx. ₹20)
Jumper Wires (Approx. ₹100)
Breadboard (Approx. ₹300)
5V Power Supply for LED strip (Approx. ₹500)

3. Arduino IDE Setup

Install the latest Arduino IDE.
Install ESP8266 or ESP32 board support via Boards Manager.
Install the Adafruit NeoPixel library via Library Manager.
Connect your ESP board to your PC via USB.
Select your board and COM port in Tools.

4. Wiring the Components

Connect the WS2812 data pin to a digital pin on ESP (e.g., D2/ GPIO4).
Power WS2812 with 5V and GND (separate from ESP if needed).
Connect the LDR in a voltage divider with a 10kΩ resistor to analog input (A0).
Add a 1000µF capacitor across LED strip power to prevent power spikes.
Ensure all grounds are common (ESP + LED strip + LDR).

5. Arduino Code

Upload this code to your ESP board to control the WS2812 strip via WiFi and LDR sensor:

#include <Adafruit_NeoPixel.h>
#include <ESP8266WiFi.h> // For ESP8266, use ESP32WiFi.h for ESP32
#include <ESPAsyncWebServer.h>

#define LED_PIN D2
#define NUM_LEDS 16
#define LDR_PIN A0

Adafruit_NeoPixel strip(NUM_LEDS, LED_PIN, NEO_GRB + NEO_KHZ800);
AsyncWebServer server(80);

int brightness = 128; // default brightness

const char* ssid = "Your_SSID";
const char* password = "Your_PASSWORD";

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

  server.on("/", HTTP_GET, [](AsyncWebServerRequest *request){
    String html = "<html><body>";
    html += "<h2>LED Controller</h2>";
    html += "<a href='/on'>Turn ON</a><br>";
    html += "<a href='/off'>Turn OFF</a><br>";
    html += "</body></html>";
    request->send(200, "text/html", html);
  });

  server.on("/on", HTTP_GET, [](AsyncWebServerRequest *request){
    setColor(255, 0, 0); // Red example
    request->send(200, "text/plain", "LEDs ON");
  });

  server.on("/off", HTTP_GET, [](AsyncWebServerRequest *request){
    setColor(0, 0, 0);
    request->send(200, "text/plain", "LEDs OFF");
  });

  server.begin();
}

void loop() {
  int ldrValue = analogRead(LDR_PIN);
  brightness = map(ldrValue, 0, 1023, 50, 255); // dim if bright room
  strip.setBrightness(brightness);
  strip.show();
  delay(100);
}

void setColor(int r, int g, int b){
  for(int i=0;i<NUM_LEDS;i++){
    strip.setPixelColor(i, strip.Color(r,g,b));
  }
  strip.show();
}

6. How It Works

The ESP board connects to WiFi and hosts a simple web server. You can turn the LEDs on/off or set colors via browser links. The LDR sensor reads ambient light, adjusting brightness automatically. The NeoPixel library controls each WS2812 LED individually, allowing smooth color changes and patterns. PWM brightness control ensures the strip dims in bright conditions to save energy.

7. Testing Your Project

Upload the code to ESP8266/ESP32 and connect to WiFi.
Access your ESP’s IP in a browser to see the control page.
Test turning LEDs on/off via links.
Cover/uncover LDR to see brightness adjust automatically.

8. Advanced Modifications

Add multiple color patterns via additional web links.
Use mobile-friendly HTML interface with sliders for color selection.
Integrate time-based automation or triggers based on motion sensors.
Add more LED strips by increasing NUM_LEDS and wiring in series.
Use MQTT for cloud-based smart home control.

9. Common Issues and Troubleshooting

LEDs not lighting – Check power supply, data pin, and common ground.
Web page not loading – Ensure ESP is connected to correct WiFi network.
LDR not affecting brightness – Check wiring and analog pin mapping.
Flickering LEDs – Add a large capacitor across power or reduce strip length per power source.

10. Learning Insights

How to host a simple web server on ESP8266/ESP32.
Controlling WS2812 LEDs individually and as a strip.
Using sensors (LDR) to automate behavior based on environment.
Basics of WiFi IoT for smart home applications.
Mapping analog inputs to brightness values for dynamic effects.

11. Conclusion

This WiFi-controlled WS2812 LED strip project combines remote control, automation, and dynamic lighting in a smart home-friendly package. It teaches ESP8266/ESP32 programming, web server basics, NeoPixel control, and sensor integration. Experiment with colors, patterns, and triggers to create a fully customized smart lighting system!

By Kaushal Haladi

Search ArduNova