DIY Clap-Activated LED Light

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3D Printed LED Light

Problem Statement

I wondered what it takes to create an LED light that can be turned on and off by a clap. Having no prior experience in electronics, I decided to design and build a 3D-printed clap-activated LED light.

How Does It Work?

A normal LED light turns on when current flows through it. If we connect a battery directly, it will stay on until the battery dies. By adding a switch, we can open and close the circuit, turning the LED on and off.

Now, instead of a physical switch, I used a microcontroller + sound sensor. The sound sensor converts sound waves into electrical signals. The Arduino continuously checks this signal and only triggers the LED when the sound exceeds a set threshold. A clap produces a strong enough sound spike, so the Arduino recognizes it and switches the LED on or off.

That’s how a clap-activated LED light works.

Core Components of This Project

  • Arduino Nano – microcontroller to store the program and control the LED

  • Sound Sensor Module (KY-038) – converts sound into an electrical signal

  • LED Strip (WS2812B) – provides the lighting

Supporting Components

  • AC-DC Adapter – converts 110V/240V AC to 5V DC

  • Resistor (220 Ω)

  • Capacitor (1000 µF, 6.3V)

Mechanical Design

I designed two 3D-printed parts that form the word 作 (saku), which means “to create” or “to build.”

  • Base: Holds the LED strip around the inner wall. The lower and upper parts have different thicknesses to stop the cover from sliding all the way through.

  • Cover: Designed 0.2 mm smaller than the base’s inner diameter so it fits snugly but doesn’t fall through.

Custom PCB

This was the key to the project. A breadboard with jumper wires was too bulky and messy to fit inside the housing. Thanks to PCBWay for sponsoring the PCB — it simplified everything into a single compact board.

Programming

The Arduino code listens to the sound sensor and toggles the LED strip when a clap is detected.


#include 
#define SOUND_SENSOR_PIN A0
#define LED_PIN 6
#define NUM_LEDS 70
#define SOUND_THRESHOLD 540
#define BRIGHTNESS 150 // Lower brightness (0-255)

Adafruit_NeoPixel strip = Adafruit_NeoPixel(NUM_LEDS, LED_PIN, NEO_GRB + NEO_KHZ800);

bool ledsOn = false;
bool soundExceededThreshold = false;

void setup() {
  Serial.begin(9600);
  strip.begin();
  strip.setBrightness(BRIGHTNESS); // Set brightness to lower level
  strip.show(); // Initialize all pixels to 'off'
}

void loop() {
  int soundValue = analogRead(SOUND_SENSOR_PIN);
  Serial.println(soundValue); // Print the sound value for debugging

  if (soundValue > SOUND_THRESHOLD) {
    if (!soundExceededThreshold) {
      ledsOn = !ledsOn;
      soundExceededThreshold = true;
    }
  } else {
    soundExceededThreshold = false;
  }

  if (ledsOn) {
    turnOnLeds();
  } else {
    turnOffLeds();
  }

  delay(50); // Small delay to avoid rapid flickering
}

void turnOnLeds() {
  for (int i = 0; i < NUM_LEDS; i++) {
    strip.setPixelColor(i, strip.Color(255, 120, 0)); // Set color to white
  }
  strip.show();
}

void turnOffLeds() {
  for (int i = 0; i < NUM_LEDS; i++) {
    strip.setPixelColor(i, strip.Color(0, 0, 0)); // Turn off LED
  }
  strip.show();
}

Final Result

The LED lights up when I clap in front of the sensor. Surprisingly, it even works from a few meters away. By tweaking the Arduino code, the LED strip can also change colors based on different triggers.

You can watch the video of this project here.

Problems & Improvement Ideas

  • The sound sensor isn’t very accurate. Sometimes it reacts to background noise, and lowering the sensitivity makes it harder to detect claps.

  • In future iterations, I would consider using a MAX9814 microphone module for more reliable sound detection, or even explore a voice recognition module for spoken commands.

Lessons Learned

This was my first personal electronics project, and I learned a lot about voltage and current requirements.

  • The power source must match the voltage (in this case, 5V DC from the adapter).

  • The supply must provide enough current for all components combined, or risk overheating and failure.

  • Always choose a power supply that can handle slightly more current than required.

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